A' -1 r \ 2 % 2- "^ Z^Z ^: / •,:5LUl TRANSACTIONS OF THE / AMERICAN PHILOSOPHICAL SOCIETY. HELD AT PHILADELPHIA, FOR PROMOTING USEFUL KNOWLEDGE. VOLUME ir. PHILADELPHIA: PRINTED AND SOLD BY ROBERT AirKEN, AT POPE's HEAD IN MARKET STREET. M.DCCLXXXVI. ( iii ) ADVERTISEMENT. ■^ H E peculiar circumftances of Americaj, fmce the publication of the firll volume of the Tranfa6lions of this Society, will be a fufficient apology for the long delay in pub- liiliing a fecond. The Society having, how- ever, refumed their former labours in pro- moting ufeful knowledge, which were necef- farily fufpended during the late war: and finding themfelves in poileffion of materials more than fufficient for a fecond volume of Tranfadions, appointed a Committee to felecl fuch pieces as might be moil proper for that purpofe : The Committee have made that fe- le6lion,' which is here offered to the public. Several pieces flill remain worthy of publica- tion, which will probably appear in a future volume. It IV Advertisement. It may not be amifs in this place to infeit the Rules which the Society have adopted for the diredlion of their Committees in the choice of papers for publication. First, " That the grounds of the Com- " mittee's choice of papers for the prefs, fhould " always be the importance or fingularity of *' the fubjefts, or the advantageous manner of " treating them, without pretending to an- *' fwer, or to make the fociety anfwerable, *' for the certainty of the fa6ls, or propriety *' of the reafonings, contained in the feveral ** papers fo publifhed, which muft Hill reft on *' the credit or judgment of their refpedlive " authors. Secondly, " That neither the Society, nor ** the Committee of the prefs, do ever give " their opinion as a body, upon any paper " they may publilh, or upon any fubje6t of *' Art or Nature that comes before them." LAWS y^ r V ) LAWS AND REGULATIONS^ OF THE American PHILOSOPHICAL SOCIETY' Held at P HILADELP HIA, for promoting USEFUL KNOB' LEDGE. 'WO focieties having formerly fubfifted in Philadel- phia, whole views and ends v\'ere the fame, viz. " the adiiaticement of iifefid knoivledge" it was judged that their union would be of public advantage; and they were accordingly united January 2d, 1769, by a certain Fundamental Agreement ; the chief Articles of which are, Fhjl^ That the name of the United Society fhall be The American Philofophical Society-, held at Philadelphia., for promoting iijeful Knozvledge. Secondly., That there fhall be the following officers of the fociety, viz. one Patron-, one Preftdent-, three Vice- PrefidentSt one Treafurer-, four Secretaries., and three Cu- rators. Thirdly., That all the above officers fhall be chofea annually by ballot, at the firft meeting of the Society in January ; excepting only that inflead of eletting a Patron, the Governor of the Province be requefted to be Patron, Other Laws were to be made by the United Society ; and accordingly the following LAWS, &c. were pafl'ed February 3d, 1769. L Of the annual Payments to he made by Members. Every Member of this Society fhall fubfcribe Ten Shil- lings yearly, to be applied by the Society to fuch purpo- fes VI L A W S, See. fes as they fhall diredl; and no Member fliall be intitled to a vote in the annual eleftion of oflicers, unlefs it ap- pears that he has paid into the hands of the Treafurer, the fubfcription of the preceding year, and all former arrears, if any there were. Every Member hereafter to be chofen, agreeable to the Laws of this Society, fhall pay Ten Shillings admiflion mo- ney, and allb fubfcribe for the yearly payment of Ten ShillmgSt before he is intitled to have any vote in the bu- fmefs of the Society at their meetings. II. Of the Ele^ion of Members. The eledtion of new Members fhall be by ballot, and that only on the third Friday in the months of January, April, July and Odober; and in order to fuch eledion at leaft twenty Members muft be prefent. Any Member may, at any meeting, propofe fuch per- fon or perfons, as he thinks proper to be a Member or Members of this Society ; but no perfon fhall be ballotted for, unlefs his name, together with the name or names of the Member or Members who propofed him, has been fix- ed up by the Secretaries for the view of the Society, at the two meetings preceding the time of eledion. Nor fhall any perfon be deemed duly chofen unlefs three-fourths of the votes of the whole Members be in his favour. III. Of the Officers-, and manner of their ele^ion. The eledion of fuch Officers as are to be chofen in this Society, fhall be on the firft Friday in January every year, by ballot or written ticket, between the hours of two and five in the afternoon, at fuch place in this city as ihall be fixed by the Society at their previous meeting on the third Friday in December every year ; of which notice fhall be given in the Gazette, or fuch other public papers as the Society LAWS, &c. vll Society fhall order, at leaft one week before the day of ele£lion. Before opening the ele£lion, the company that fhall be met at half an hour after two, fhall appoint three Mem- bers of the Society as judges of the eledlion, and alfo two clerks or fecretaries, for taking down the names of the voters. And in cafe of an equality of votes for any Offi- cer, after cafling up the ballots, the decifion fhall be by lots, to be drawn by one of the judges. IV. Of the Preftdent. The Prefident is to prcfide at all meetings, to preferve order, to regulate the debates, and to flate and put que- ftions, agreeable to the fenfe and intention of the Members, V. Of the V'lce-Prefidents, In the abfence of the Prefident^ his duty fhall devolve on the Vice-Pref debits., fo that they fhall prefide alternate- ly at meetings. But if the Vice-Prefident, whofe turn it is to prefide at any meeting, fhould be abfent, his place fliall be fupplied by any of the other Vice-Prefidents, who fhall be prefent, according as he may be next in turn. If only one Vice-Prefident be prefent, he fhall of courfe pre- fide ; and if neither the Prefident, nor any Vice-Prefident be prefent, the Members met, flaall appoint one of their number to take the chair for that meeting. VI. Of the Treafurer. The Treafurer fliall receive the fubfcriptions of the Members, and all other monies that may become due to the Society, and fliall pay the fame agreeable to their or- ders, certified to him by the Prefident, Vice-Prefident or Member, who was in the chair when the order was made. The ■vrii LAWS, &c. The Treafurer fi^all keep a regular account of all monies received and paid by him as aforefaid; and once every year, or oftener if required by the Society, he fliall render an account to them of the ftock in his hands, and the dif- burfements made by their order, and fhall deliver up to his fucceflbr the books and all papers belonging to them, together with the balance of cafli in his hands. And for the faithful difcharge of his truft, he fhall, before he en- ters on his office, give bond and fecurity to the Prefident and Vice-Prefidents, in double the fum which they, or any three of them, fhall judge he may probably become entrufted with during his faid office. VII. Of the Secretaries. The Secretaries fhall fo fettle matters as to take equal fhares of all bufinefs, and fo as that two of them fliall ferve at every meeting, viz. one to take the minutes, and one to read all letters and papers that may be communi- - cated to the Society. It is alfo the bufmefs of the two Secretaries of each particular meeting, to copy into the minute-book the proceedings of that meeting, in order to produce the fame fair to the next meeting. They are fur- ther to copy into the proper books all fuch letters, papers and effays, as the Society may think fit to preferve on re- cord, and to have the fame ready to be laid before the next meeting. The other two Secretaries are, in the mean while, to give notice to new members of their eledlion, and agree- able to the dire£i:ions of the Society, to write or anfvver letters; and, in general, io 7na7iage all matters cf cor re- J'pondence. The Secretaries may, for their own eafe, change places; fo that the two who have ferved as cor ref ponding Secreta-- riest for one month or limited time, fliall take their turn to ferve for the like time as fittim^ or attendinty- Secretaries. -^ ^ ^ WW. Of L A W S, &CC. ix VIII. 0/ the Curators. The bufinefs of the Curators (hall be to take charge of, and preferve, all Specbnens of natural Produciions, whe- ther of th^ Ani?iial, Vegetable or FoJJll kingdom ; all mo- dels of machines and inftruments, and all other matters and things belonging to the Society, which ihall be com- mitted to them ; to clafs and arrange them in their pro- per order, and keep an exadl lift of them, with the names of the refpedllve donors, in a book provided for that pur- pofe; which book fhall be laid before the Society, as often as called for. The Curators, on entering upon their office, fhall give fuch a receipt for every thing that is committed to their charge, as the Society fhall think proper; and, at the end of their term, fhall deliver up the fame to their fucceflorsi For the faithful performance of their duty, and of the truft repofed in them, they fhall give bond to the Prefi- dents and Vice-Prefidents, in fuch a fum as they, or any three of them, fhall require. IX. Of the Meetings of the Society. The ordinary meetings of the Society fhall be on the firft and third Fridays of every month, from October to May, both inclufive, at fix o'clock in the evening, and on the third Friday in each of the other four months at feven o'clock. No meeting fhall be continued after ten o'clock, nor any new matter be introduced by motion, or otherwife, after nine o'clock. X. Of the Difpofition of Money ^ and making neiv Laws. No part of the Society's flock fhall be difpofed of in Premiimst or otherwife, nor fhall any new laws be made, b until X LAWS, &c. until the fame have been propofed at one meeting, and are agreed to by two-thirds of twenty or more Mem- bers prefent at a fubfequent meeting. XI. Of other Proceedings of the Society. No queftion fhall be put on a motion.^ unlefs the motion hefeconded ; and the determination of any quellion fhall be by ballot^ inftead of open fufFrage, if defired by any four Members. In cafe of an equaHty of votes on any queftion, the fame fhall be deferred to another meeting. When any Member fpeaks he fhall ftand up, and ad- drefs himfelf to the chair, and the reft fhall remain filent in their feats. When two or more offer to fpeak at the fame time, the prefiding Member, in that, as in other matters of order, fhall regulate and determine who fhall fpeak firft. Xll. Of Committees.. The Members of this Society fhall be clalTed into one or more of the following Committees. 1. Geography, Mathematics, Natural Philofophy and Aftronomy. 2. Medicine and Anatomy. 3. Natural Hiftory and Chemlftry. 4. Trade and Commerce. 5. Mechanics and Architefture. 6. Hufbandry and American Improvements. Thefe Committees fhall meet on their own adjournments, and at fuch other times as the Society fhall appoint, for the confideration of any matters referred to them, and fhall have power to chufe their own chairman. But no Committee, as fuch, fhall take up any new bufinefs of the Society, but fhall confine themfelves only to the fubjedls for which they are appointed, and to matters referred to them by the Society. ( xl ) An ACT for Incorporating the American Philofophical Society i held at Philadelphia., for Promoting ufeful Kno'uoledge. WHEREAS the cultivation of ufeful knowledge, and the advancement of the liberal arts and fciences in any country, have the moft diredt tendency to- wards the improvement of agriculture, the enlargement of trade, the eafe and comfort of life, the ornament of Ibci- ety, and the increafe and happinefs of mankind. And ivhereas this country of North-America, which the good- nefs of Providence hath given us to inherit, from the vaft- nefs of its extent, the variety of its climate, the fertility of its Toil, the yet unexplored treafures of its boweh, the multitude of its rivers, lakes, bays, inlets, and other con- veniencies of navigation, offers to thefe United States one of the richeft lubjeds of cultivation, ever prefented to any people upon earth. And inhereas the experience of ages fhews that improvements of a public nature, are beft car- ried on by focieties of liberal and ingenious men, uniting their labours, without regard to nation, fedt or party, in one grand purfuit, alike interefting to all, whereby mu- tual prejudices are worn off, a humane and philofophical fpirit is cherifhed, and youth are ftimulated to a laudable diligence and emulation in the purfuit of wilclom. And ivhereas-, upon thefe principles, divers public fpirited gen- tlemen in Pennfylvania, and other American ftates, did heretofore unite themfelves, under certain regulations, into one voluntary fociety, by the name of " The Ameri- *' can Philofophical Society, held at Philadelphia for pro- *' ^noting ufeful Knoivledge,''^ and by their fuccefsful la- b 2 hours xu CHARTER. hours and invefligations, to the great credit of America, have extended their reputation fo far, that men of the ftrft eminence in the republic of letters in the moft civilized nations in Europe, have done honour to their publications, and defired to be enrolled among their members. And ivhereas the Society, after having been long interrupted in their laudable purfuits by the calamities of war, and. the dirtrefles ot our country, have found means to revive their defign, in hopes of being able to profecute the fame with their former fuccefs, and being further encouraged therein by the public, for which purpofe they have pray- ed us, The Reprefentati'ues of the Freemen of the Common- ivealth of P ennfyl'vania^ that they may be created one body politic and corporate forever, with iuch powers, pri- vileges, and immunities, as may be neceflary for anfwer- ing the valuable purpofes which the faid Society had ori- ginally in view. Wherefore-, in order to encourage the faid Society in tha profecution and advancement of all ufeful branches of knowledge, for the benefit of their country, and of man- kind ; Be it enatied., and it is hereby enacted., by the Re^ prefentatives of the Freemen of the Commonivealth of Penn^ fyl'uama in General AffembJy met., and by the authority of the fame., That the members of the faid American Philo- fophical Society heretofore voluntarily alfociated for pro- moting ufeful knowledge, and fuch other perfons as have been duly eleded members and officers of the fame agree- ably to the fundamental laws and regulations of the faid Society, comprifed in twelve fetftions, prefixed to their volume of Tranfadions, publiflied in Philadelphia by Wil-^ liam and Thomas Bradford., in the year of our Lord one thoufand feven hundred and feventy-one ; and who fhall in all rel'pe€ts conform thcmfelves to the faid laws and re- gulations, and Inch other laws, regulations and ordinan- ces, as fliall hereafter be duly made and enadted by the faid Society, according to the tenor hereof, be, and for- ever CHARTER. xHJ ever hereafter fhall be one body corporate and politic in' deed, by the name and Ityle ot The American Philofophi-' cal Society-, held at P biladelpbia, for promoting ufcfiil knowledge., and by the fame name they are hereby con- ftituted and confirmed one body corporate and politic, to have perpetual fucceilion, and by the fame name they and their lucceflbrs are hereby declared and made able and ca- pable in law, to have, hold, receive, and enjoy lands, te- nements, rents, franchiies, hereditaments, gifts and be- quefts of what nature foever, in fee-fimple, or for term of life, lives, years, or otherwife, and alfo to give, grant, let, fell, alien, or aflign the fame lands, tenements, here- ditaments, goods, chattels, and premifes, according to the nature of the refpedlive gifts, grants and bequefts, made to them the fald Society, and of their eftate therein. Froijided, That the amount of the clear yearly value of fuch real eftate do not exceed the value of ten thoufand bufhels of good merchantable wheat. Jnd be it further enabled by the authority aforefaid., That the laid Society be, and fhall be for-ever hereafter- able and capable in law to fue, and be fued, plead and be impleaded, anfwer and be anfwered unto, defend and be' defended, in all or any of the courts or other places, and before any judges, juiiices, and other perfon and per— fons, in all manner of adions, luits, complaints, pleas,; caufes and matters, of what nature or kind foever, with- in this commonwealth ; and that it fhall and may be law- ful to and for the faid Society, for-evcr hereafter to have and ufe one common leal in their affairs, and the fame at their will and pleafure to break, change, alter and renew. And be it further enaBed by the authority aforefoidy That for the well governing the faid Society, and order- ing their affairs, they fhall have the following officers, that is to fay, one Patron, who fhall be his Excellency the Prefident of the Supreme Executive Council of this commonwealth, for the time being, and likewifeone Pre- fident, XlV CHARTER. fident, three Vice-Prefidents, four Secretaries, three Cu- rators, one Treafurer, together with a Council of twelve Members ; and that on the firft Friday of January next, between the hours of two and five in the afternoon, as many of the members of the faid Society as {hall have paid up their arrears due to the Society, and fhall declare their willingnefs to conform to the laws, regulations and ordi- nances of the Society, then duly in force, according to the tenor hereof, by fubfcribing the fame, and who fhall attend in the hall, or place of meeting of the faid Society, within the time aforefaid, fhall choofeby ballot, agreeably to the fundamental laws and regulations herein before re- ferred to, one Prefident, four Secretaries, three Curators, and one Treafurer, and at the fame time and place, the Members met and qualified as aforefaid, fhall in like man- ner choofe four Members for the Council, to hold their offices for one year, four more Members for the Council to hold their offices for two years, and four more Mem- bers for the Council to hold their offices for three years. And on the firfi: Friday in January, which fliall be in the year of our Lord one thoufand feven hundred and eighty- two, and fo likewife on the firft Friday of January, yearly and every year thereafter, between the hours of two and five in the afternoon, the Members of the faid Society met and qualified as aforefaid, fhall choofe one Prefident, three Vice-Prefidents, four Secretaries, three Curators and one Treafurer, to hold their refpedtive offices for one year ; and four Councilmen, to hold their offices for three years. Provided., That no perfon refiding within the United States fhall be capable of being Prefident, Vice-Prefident, Secretary, Treafurer, or Member of the Council, or of ele£ling to any of the faid offices, who is not capable of elefting and being clefted to civil ofhces within the ftate in which he refides. Provided aJjoi That nothing here- in contained, fhall be confidered as intended to exclude any of the faid officers or counfellors, whofe times fhall be CHARTER. XV expired, from being re-eledled, according to the pleafure of the faid Society ; and of the day, hours, and place of all fuch ele£lions, due notice fhall be given by the Secre- taries, or fome one of them, in one or more of the pub- lic news-papers of this ftate, agreeably to the faid funda- mental laws and regulations before referred to. Ajid be it further ena^ed by the authority aforefaidy That the officers and council of the faid Society fhall be capable of exercifing fuch power for the well governing and ordering the affairs of the Society, and of holding fuch occafional meetings for that purpofe, as fliall be de- fcribed, fixed, and determined by the ifatutes, laws, regu- lations and ordinances of the laid Society, hereafter to be made. Provided alivays. That no ffatute, law, regulati- on or ordinance fhall ever be made or palled by the faid Society, or be binding upon the Members thereof, or any of them, unlefs the fame hath been duly propofed, and fairly drawn up in writing, at one flated meeting of the Society, and enacfted or paffed at a fubfequent meeting at leaft the fpace of fourteen days after the former meeting, and upon due notice in lome of the public news-papers, that the enacting of ffatutes and laws, or the making and pafhng ordinances and regulations, will be part of the bu- finefs of fuch meeting ; nor rtiall any flatute, law, regu- lation or ordinance be then or at any time enadled cr paf- fed, unlefs thirteen Members of the faid Society or fuch greater number of Members as may be afterwards fixed by the rules of the Society be prefent, beiides fuch quo- rum of the officers and council as the laws of the Society for the time being may require, and unlefs the fame be voted by two-thirds of the whole body then prefent ; all which ftatutes, laws, ordinances and regulations lo as aforefaid duly rnade, enabled and palfed, Ihall be binding upon every Member of the faid Society, and be from time to time inviolably obferved, according to the tenor and cffed thereof; provided they be not repugnant or con- trary Kx'i CHARTER. trary to the laws of this commonwealth, for the time be- ing in force and efFedl. A'tidivhereas nations truly civilized (however unhappily at variance on other accounts) will never wage war with the arts and fciences and the common interefts of humanity. Be it further enacted by the authority afore/aid., That it fhall and may be lawful for the faid Society, by their proper officers, at all times, whether in peace or war, to correfpond with learned focieties, as well as individual learned men, of any nation or country, upon matters merely belonging to the bufinefs of the faid Society ; fuch as the mutual communication of their difcoveries and pro- ceedings in philofophy and fcience; the procuring books, apparatus, natural curiofities, and fuch other articles and intelligence as are ufually exchanged between learned bo- dies for furthering their common purfuits. Pro'vided al- *wayst That fuch correfpondence of the faid Society be at all times open to the infpedlion of the Supreme Executive Council of this commonwealth. (Signed) JOHN BAYARD, Speaker. EnaSled into a Laiv at Philadelphia., on Wednefday the fifteenth day of March., Anno Domini one thoufand feven hun- dred and eighty. (Signed) THOMAS PAINE, Clerk of the General AJfanbly. (Copy) ( xvil ) ^ Latv to encreafe the annual Subfcrlptions of the Members of the American Phllofophical Society held at Philadel- phia for promoting ufeful knoivledgCt and alfo to encreafe the Depofites of neivly ele^ed Members on their adviiffion into the f aid Society, WHEREAS the cuftomary annual payment of Ten Shillings from each Member of the American Phllofophical Society, and alfo the cuftomary depofite of Ten Shillings by each newly eledted Member, on his ad- million into the fald Society, hath been found inadequate to the neceffary and occafional expenditures of the Society. Be it therefore enadted, and it is hereby enadted by the American Philofophical Society, held at Philadelphia for promoting ufeful knowledge, by virtue of 'the chartered rights to the faid Society granted, and by authority of the fame. That for the future, that is to fay, from and after the firft of March next, the payments to be made by every Member of the faid Society (hall be Four Dollars annual- ly, and the depofite to be made by every ne.vly eleded Member, from and after the faid firft of March, fhall be Ten Dollars. And no Member who {hall be in arrear for his annual fubfcription or depofite, ft^all be eligible to any office in the faid Society, or be permitted to vote at elec- tions, or at the ordinary meetings of the Society, until he Ihall have fully paid up his faid arrears. And be it further cnafled, That no newly eledled Mem- ber fhall receive a certificate of his election, or be ad.nit- ted as a Member of the faid Society, until he (hall have paid into the treafury the faid depofite of Ten Dollars and alfo his arrearages of Four Dollars per annum, if any fuch ihall have accrued from the time of his eledion. C Provided .T.m L.'.W co^xERNING. SUBSCRIPTIONS, &c. Provided always, That honorary Members in foreign parts, fliall not be fubjedt to this law, nor fhall their cer- tiiicates of clciftion be with-hcld on account of their not paying the depofite or annual fubicription aforefaid. Ne- verthelefs, if any fuch foreign Member fhould happen to come to the city of Philadelphia with a view of fettlement or refidence, then fuch Member fliall pay the depofite money as before direfted, and fliall thenceforth be liable for the annual fubfcription in common with other refident Members. And be it further enabled. That all former laws, ordi- nances or cufloms inconfiftent with or contradidtory to this a<3:, be, and the fame are hereby repealed. EnaSied into a laiv at a meeting of the American Philojo- phical Society.) according to Charter.) this Jtxth day of. 'January^ Anno Domini.) one thoufandfeven hundred and eighty-fix. Ex' ( six ) Ext ra£ls from the Minutes of the American Philofoph'ical Society, refpeUing a Donation propofed by Mr. J. H. de Magellan, of London. January 1786, MR. J. H. de Magellan of London, having in a let- ter, dated the 1 7th of September laft, and com- municated to the fociety by Mr. Vaughan, one of the Vice-Prefidents, made an offer to the fociety of tivo hun- dred gumeas, to be vefted in a permanent fund, that the intercft arifing therefrom may be dlfpofed of in annual pre- miums, to the authors of the beft difcoveries or moft ufe- ful improvements relating to navigation, or to natural philofophy, mere natural hiftory only excepted: And the Ibciety having moft thankfully accepted the generous offer, appointed a committee to frame rules and conditions for the difpofition of the propofed premiums, agreeable to the intention of the donor, expreffed in his letter, but more precife in the terms; which being done, and approved of by the fociety, were immediately tranfmitted in a letter to Mr. Ma2:ellan, for his confirmation or amendment. They are as follow, viz. I. The candidate fhall fend his difcovery, invention or improvement, addreffed to the Prefident or a Vice-Prefi- dent of the Society, free of portage or other chari!;es ; and fhall diftinguifh his performance by fome motto, device or fignature, at his pleafure. Together with his difcovery, invention or improvement, he fhall alfo fend a fealed let- ter, containing the fame motto, device or fignature, and fubfcribed with the real name and place of refidence of the author. 2. Perfons XX EXTRACTS from the MINUTES of thf. 2. Perfons of any nation, feci, or denomination what- ever, fhall be admitted as candidates for this premium. 3. No difcovery, invention or improvement (hall be- entitled to this premium, which hath been already pub-- lifhed, or for which the author hath been pubHcly re- warded elfewhcre. 4. The candidate fhall communicate his difcovery, in- vention or improvement either in the Englifh, French, German, or Latin language. 5. All fuch communications fhall be publicly read or exhibited to the Society, at fome flated meeting, not lef& than one month previous to the day of adjudication ; and fhall at all times be open to the infpedtion of fuch mem- bers as fhall defire it. But no member fhall carry home with him the communication, defcription or model, ex- cept the officer to whom it fhall be entrufted : nor fhall fuch officer part with the fame out of his cuftody, to any but the judges, who may demand it for confideration. 6. The twelve counfellors, together with the other of- ficers annually elected according to the charter and laws of the Society, fhall be judges of the merits of the feveral communications, and award the premium. Which adju- dication fhall be determined by a majority of judges met; provided that fuch majority be not lefs than {even con- curring votes. J. And for this purpofe the counfellors and other offi- cers, or at leaft feven of them, fhall meet on the fecond Monday in December, in every year, to form their judg- ment and award the premium. After due confideration had, a vote fhall firO: be taken on this queftion, viz. " Whe- *' ther any of the communications then under infpe(flion, " are worthy of the propofed premium ?" If this fliall be determined in the negative, the whole bufinefs fhall be deferred till another year : But if in the affinuatiire, the judges lliall then proceed to determine, by vote, the dif- covery, invention or improvement moft ufeful and worthy. And PHILOSOPFIICAL SOCIETY. xxr And that difcovery, invention or improvement which fliall be found to have the greateft number of concurring votes (;being not lefs than feven) in its favour, fhall be fuccefs- ful. Whereupon a certificate in writing fliall be forthwith drawn of this adjudication, and figned by thoie who voted for the crowned fubjedt : And then, and not till then, the fealed letter accompanying the crowned performance, fliall be opened and the name of the author announced ; which certificate Audi be prefented to the Society at their next ftated meeting, and delivered to the Secretary to be enter- ed on record, in a bound book provided for this purpofe.. 8. A full account of the crowned fubjeft fliall be pub- liflied by the Society as foon as may be, after the adjudica- tion, either in a feparate publication, or in the next fucceed- ing volume of their Tranfadions, or in both. 9. The unfuccefsful performances fliall lie over for con- fideration, and remain, as candidates for the premiuFo^ for Jive fucceeding years next after their prefentment ; unlefs the author or authors fliall think fit to withdraw them or any of them : And the Society fliall publifli annually an abftraft of the titles, objeit or lubjed matter of the com- munications fo under confideration, fiich only excepted as the counfellors and other officers fliall, by vote as aforefaid, have determined not worthy of public notice. 10. No counfellor or officer who is a candidate fliall fit in judgment, or give his vote. 1 1. The letters containing the names of authors whofe performances fliall be rejeded, or fliall be found unfuc- cefsful after a trial of five years, fliall be burnt without breaking the feals. I 2. In cafe there fliould be a failure, in any year, of any communication worthy ot the propofed premium, there will then be two premiums awarded in the next year. But no accumulation of premiums iliall entitle an author to more than one premium for any one difcovery, invention or improvement. 13. The- xxU EXTRACTS from the MINUTES, &c. 13. The premium fhall confift of an oval plate of foil d flandard gold, of the value of Ten Guineas. On one fide thereof fhall be neatly engraved the following motto, • together with thefe w^ords, The donation of of London^ ejlahlijhed in the year 1786. And on the other fide of the plate fhall be engraved thefe words, Aivarded by the A. P. S. to for his difcovery of A. D. 1 7 — . Prefident. And the feal of the Society fhall be annexed to the faid golden plate, by a ribbon palfing through a fmall hole near the lower edge therco£ LIST ( xxiii ) LIST OF THE OFFICERS OF THE AMERICAN PHILOSOPHICAL SOCIETT, ■Held at Philadelphia, for promoting ufeful Knowledge, For the Year 1786. Patron. His Ex"^ the Prefident of the Supreme Execu- tive Council of the Commonwealth, for the time being,. President. His Excellency Dr. Benjamin Franklin, Efquire, L. L. D F. R. S. &c. &c. f Rev. Dr. John Ewing, Provofl: of Vice-Presidents ] ^^^ UniVerfity of Pennfylvania. YlCE-t-RESIDENTS. j ^^^ ^^, William White. [Samuel Vaughan, Efq. fDr. James Hutchinfon. Mr. Robert Patterfon, Profeffor of Mathematics in the Univerfity of Pennfylvania. Rev. Dr. Samuel Magaw, Vice-Pro- voft of the Univerfity of Penn- fylvania. Dr. John Foulk. Secretaries. Curators.. Treasurer. fDr. Samuel Duffield. ] Dr. Barnabas Binney. j William Bradford, Efq. Attorney |_ General of Pennfylvania. fThe Honorable Francis Hopkin- •^ fon, Efq. Judge of the Admiralty L in Pennfylvania, Co UN— XXIV Counsellors. LIST OF OFFICERS. The Hon. Thomas M'Kean, Erqulre, L. L. D. Chief Juftice of the Su- preme Court of Pennfylvania. The Hon. George Bryan, Efquire, a Juftice of the Supreme Court of Pennfylvania. Sieur Barbe de Marbois. Mr. Samuel Caldwell. Jared Ingerfoll, Efq. Jonathan Bayard Smith, Efq. Rev. Mr. Robert Blackwell. David Rittenhoufe, Efq. Dr. Benjamin Rufh, ProfefTor of Che- miftry in the Univerfity of Penn- fylvania. Dr. John Jones. Dr. Adam Kuhn, Profeflbr of Mate- ria Medica in the Univerfity of Pennfylvania. Rev. Mr. George DufEeld. LIST of Members of the American Philosophical So- ciety, elefted fince the Publication of the Firfl Vohime of Tranfa£lions, viz. fince the i8th of January, 1771. T ^ J OSEPH Aftolinge, Efq. of Georgia. B Mr. Gerard Banker. Dr. William Bryant, of New- Jerfey. * Mr. James Bringhurft. Honorable Thomas Bee, Efq. of South-Carolina. John Beale Boardley, Efq. of Maryland. Rev. Jeremy Belknap, of New-Hampfhire. Dr. Barnsbas Binney. Rev. Mr. Robert Blackwell. William Note, Thofe Members whofe places of rcCdencc arc not fpecifieJ, arc of Phihdclphi.; ; and thofe marked with an * are deceafed. LIST OF MEMBERS. xxv William Bradford, Efq. Attorney-General of Pennfylvania. C Dr. John Carfon. Rev. ManaiTeh Cutler, of Ipfwich, Maflachuletts. D Sharp Delany, Efq. Rev. Dr. Robert Davldfon, of Carlifle. Mr. John Dunlap. E Dr. Jonathan Elmer, of New-Jerfey. Jofeph Ellicott, Efq. Bucks county. * Andrew Ellicott, Efq. of Maryland. F Mr. George Fox. Dr. John Foulk. G Mr. George Gauld, of Penfacola. Ifaac Gray, Efq. George Gray, Efq. Mr. Archibald Gamble, Profeflbr of Englifli and Oratory, Univcr- fity, Philadelphia. * Dr. Samuel F^well Griffitts. H Dr. James Hutchinfon. Thomas Hutchins, Efq. Geographer to the United States. Ebenezer Hazard, Efq. Poftmafter-General. Samuel Huntington, Efq. of Connefticut. * Rev. Dr. Juft. Hen. Chrift. Helmuth, Prof, of the Germ, and Ori- ental Languages, Univerfity, Philadelphia. Thomas Hayward, jun. Efq. of South-Carolina. I Dr. Walter Jones, of Virginia. Dr. John Jones, of Maryland. Jared IngerfoU, Efq. His Excellency Thomas Jefferfon, Efq. of Virginia, Minifter Pleni- potentiary to the Court of France. K Rev. Dr. John C. Kunze, of New- York. L Mr. Jeffe Lukens. * Henry Laurens, Efq. of South-Carolina. Rev, Mr. William Ludlam, of Leiccfler. d Dr. James ^xvi LIST OF MEMBERS, Dr. James Lloyd, of Bofton. M LIr. Archibald l^I'CIean, of York county. * Capt. John Matrefon, of New -York. Timothy Matlack, Efq. Dr. George Millegan, of South-Carolina. James M'Clurg, M. D. Williamfburgh, Virginia. Mr. Benjamin Morgan. Rev. Dr. Samuel Magaw, Vice-Provofl: of Univer. Phila. Hon. Dr. James M'Henry, Efq. of Baltimore. Rev. Dr. James Madifon, Prefident of the College of WillLam and Mary, Virginia. Rev. Mr. Henry Muhlenberg, of Lancafter. P Dr. John Perkins, of Bofton, Maflachufetts. Dr. Thomas Park. Mr. Robert Patterfon, Prof. Math. Univer. Philadelphia. Hon. Mann Page, Efq. of Frederickfburgh, Virginia. Thomas Paine, Efq. of Bordentown. Charles Pettit, Efq. R Mr. Bernard Romans, of Penfacola. S Dr. Hugh Shiell. * Jonathan Bayard Smith, Efq. f Jonrahan Dickinfon Sergeant, Efq. Rev. Dr. Samuel Smith, Vice-Pi-efident of the College in New-Jerfey. T Dr, James Tilton, of Dover. Mr. John Ternant. V Samuel Vaughan, Efq. Mr. John Vaughan. W His Excellency Ckneral Wafliington, Virginia. Rev. Samuel Williams, L. L. D. Hoi. Prof. Mor. and Nat. Philof. College of Cambridge, Maflachufetts. Dr. Nicholas Way, of Wilmington. George Wall, jun. Efq. of Bucks county. Hon. Anthony Wayne, Efq Gen. in the Armies of the United States. Mr. Benjamin Workman, Teacher of Math. Univerfity, Philadelphia. FOREIGN LIST OF MEMBERS. xxvli FOP. EIGN MEMBERS. A Monfieur le Marquis d'Argeville, of Paiis. Dr. Adams, of Barbadoes. Lieut. Stephen Adye, of the Royal Artillery. B Dr. Forbcrn Bergman, Prof. Math. Stockholm. Major Frederick F. S. dc Brahm, Triers. His Excellency M. J. Peter Van Berckel, Minifter Plenipotentiary from the United Provinces of the Netherlands. Frederick Eugene Francis Baron de Beelen Bertholf, Imperial Councellor of Commerce to the United States, Bruflels. C Le Chevalier de Chaftellux, Marflial of the Field in the Armies of France, Chevalier of the Royal Military Order of St. Louis, and one of the forty members of the French Academy. Count de Campomanes, Fifcal of the Council of Cartile. Dr. Adair Cravirford, Phyfician to St. Thomas's Hoi'pital, London. Dr. Coftc. Rev. Thomas Coombe, Ireland. Daniel Coxe, Efq. England. D Mr. Peter Dollond, of London. Dr. Andrew Duncan, of Edinburgh. Monfieur Daubenton, of the Royal Academy of Sciences at Paris. Monfieur Dubourg, of Paris. * Chev. Danmours, Conful of France for the Southern Department. E Hon. John Ellis, Efq. of Jamaica. * Hon. Bryan Edwards, Efq. of Jamaica. F Le Marquis de la Fayette, Major General in the Armies of the United States of America. Abbe Fontana, Diredor of the Great Duke's Cabinet of Natural Hiftory. G Rev. Thomas Gibbons, D. D. of London. Count de Guichen, Lieut. Gen. in the French Army. H Hon. Samuel Guftavus Baron Hermelin, of Stockholm. d 3 William xxvlii LIST OF MEMBERS. William Herfchel!, Efq. F. R. S. of Bath, England. I Dr. Hugli James, of Jamaica. K Timothy Baron de Kleingftedt, Councellor of State to the Emprefs of Ruffia. Brigadier-General Thadeus Kofcuzko. L Le Chev. de la Luzerne. Monfieur Lavoifier, of the Academy of Sciences in Paris. M Monfieur Barbe de Marbois, Intendant of St. Domingo. Lord Mahone. Monfieur INIacquer, of Paris. * Samuel Moore, Efq. of London. Dr. Benjamin Mofley, of Jamaica. Mr. John Hyacinth de Magellan, F. R. S. and Member of feveral. Academies, London. Chrift. Fred. Michaelis, M. D. of Gottenburgh. Mr. John Mandrillon, Merchant, Amfterdam. P Rev. Jofeph Prieftley, L. L. D. F. R. S. of Birmingham, England. Rev. Richard Price, D. D. F. R. S. of London. Dr. Pvobert Percival, Prof. Chym. Trinity College, Dublin. Mr. "William Parker, of London. R Monfieur le Roy, Vice-Diredtor of the Academy of Sciences in Paris.. Monfieur le Roux. Abbe Raynal. Abbe Rofier, of the Academy of Sciences in Lyons. S Monfieur S'ue, Profeflbr Royal of Anatomy, &c. at Paris. Monfieur Jean Baptifte Siie, Prof. Surgery in Paris. Right Hon. Earl of Stanhope. * Mr. Alexander Small, of London. Mr. James Six, of Canterbury. England. V Monfieur le Count de Vergennes, Minifter of State for Foreign Affairs, France. W Fortunatus de Warris, Efq. William Wright, M. D. F.R.S. in the Parifliof Trelawney, Jamaica. ( xxix ) CONTENTS O F VOLUME 11. N ° Page. I. jI LETTE R from Dr. B. Franklin, to Dr. Ingenhaufz, Phyfician to the Emperor, at Vienna, on the Catifes and Cure of Smokey Chimneys, I II. Explanation of an Optical Deception, by Mr. Rittenhoufe, 37 III. Defcription of the White Mountains in Neiu-HampfJjire, by the Rev. Mr. Jeremy Belknap, 42 IV. Defcription of a remarkable Rock and Cafcade, near the Wefiern Side of the Toughiogeny River, by Tho. Hutchins, Efq. 50 V. Letter to Mr. Nairne, of London, from Dr. Franklin, pro- pofuig a flo-wly fenfible Hygrometer for certain Purpofes, 51 VI. Defcription of a new Stove for burning of Pit coal, and con- fuming all it's Smoke, by Dr. Franklin, 57 VII. J Theory of Lightning and Thunder Storms, by Andrew- Oliver, Efq. of Salem, in the State of Maffachufetts, 74 VIII. Theory of Water-Spouts, by Andrew Oliver, Efq. loi IX. Experiments on Evaporation, and Meteorological Obferva- tions made at Bradjield in New-England, by the Rev. Samuel Williams, A. M. I18 X. A Letter from J. Madifon, Efq. to D. Rittenhoufe, Efq. containing Meteorological Obfervations, . 123" XI. Defcription of a Machine for meafuring a Ship's Way thro' the Sea, by F, Hopkinfon, Efq, ijc^ XII. Ac XXX CONTENTS. N° Page. XII. Account of an EleUrical Eel, or the Torpedo of Surinam, by William Bryant, Efq. i(,(^ XIII. Obfervations on the Numb Fifh, or Torporific Eel, by Hen- ry Collins Flagg, of South-Carolina, i yo XIV. A Letter to David Rittenhoufe, Efq. from John Page, Efq. 173 From David Rittenhoufe, Efq. to John Page, Efq. 175 Concerning a remarkable Meteor feen in Virginia and Pennfylvania. XV. Defcription of the Grotto at Swatara, by the Rev. Peter Miller, of Ephrata -, communicated by 'W\\\\3i'ca.^MX.Qn, Efq, 177 XVI. An Account of fome Experiments on Magnetifm, in a. Letter to John Page, Efq. at lVilliamfhurg,from Mr. Ritten- houfe, I 78 XVII. Ne-w Method of placing a Meridian Mark, in a Letter to the Rev. Dr. Ewing, Provofi of the Univerfity. By D. Rittenhoufe, Efq. 181 XVIII. Account of a Worm in a Horfe's Eye, by F. Hopkin- fon, Efq. 18, J XIX. An improved Method of i^iilling a Harpfichord, by F. Hopkinfon, Efq. j Sr XX. Obfervations on a Comet lately difcoveredi communicated by David Rittenhoufe, Efq. Kjt XXI. ExtraSl of a Letter from the Rev. Jeremy Belknap, co7i~ taining Obfervations on the Aurora Borealis. 1 96 XXII. A Letter from J. Madifon, Efq. to D. Rittenhoufe, Efq. containing Experiments and Obfervations upon -what are com- monly called the Sweet Springs. igy XXIII. A Letter from the Rev. Jeremy Belknap, on the preferv- ing of Par flips by drying. ipp XXIV. An Optical Problem, propofed by Mr. Hopkinfon, and folved by Mr. Rittenhoufe, 201 XXV. An. CONTENTS. xxxi N° Page. XXV. ydn Enquiry into the Caiife of the Increafc of Bilious and Intermitting Fevers in Pennfylvania, with Hints for prevent- ing them. By Benjamin Rufh, M. D. Profejfor of Chemijiry in the Univerfity of Pennfylvania, 1o6 XXVI. Jn Account of the late Dr. Hugh Martin'j Cancer Pow- der, with brief Olfcrvations on Cancers. By Benjamin Rufli, J\L D. 6c. 6c. 212 XXVII._ Maycri Obfervationes Aflronomica, 217 XXVIII. Ohfervations on the Caiife and Cure of the Tetanus, by Benjamin Rufh, M. D. 6c. 6c. 22J XXIX. Letter concerning Chimneys, addrejfed to His Excellency Benjamin Franklin, Efq. L. L. D. Preftdent of the State of Pennfylvania, and of the American Philofophieal Society, 6c. by Dr. Rufton, 231- XXX. Ohfervations on the annual Paffage of Herrings, by Mr. John Gilpin, 23(j XXXI. Ohfervations on a Solar and Lunar Ecllffe, communicat- ed to the Society by M. M. de Grauchain, Major-Ceneral of the French Squadron, 239; XXXII. An Account of the Tranfit of Venus over the Sun, June i']6g, as obferved at Newbury, in Maffachujetts ; by the Rev. Samuel Williams, A. AI. 246 XXXIII. yin eafy and accurate Method of finding a true Meri- dian Line, and thence the Variation of the Compafs. By Ro- bert Patterfon, 25 1 XXXIV. Aftronomical Ohfervations, communicated by Mr. R.it- tenhoufe, 260 XXXV. A Letter from Mr. Otto to Dr. Franklin, with a Me- moir on the Difcovery of America, 263 XXXVI. The antifeptic Virtues of Vegetable Acid and Marine Salt combined, in various Diforders accompanied with Putri- dity ; communicated in a Letter to John Morgan, M. D. F. R. S. xxxii CONTENTS. N ° Page. F. R. S. and Profejfor cf the Theory and PraBice of Phyfic at Philadelphia, by William Wright, M. D. of Trelawney in Jamaica, 284 XXXVII. Medical Hiflory of the Cortex Ruber, or Red Bark ,- communicated to John Morgan, /If. D. Profeffor of the Theory and PraBice of Phyfic at Philadelphia, and F. R. S. London, isc. 289 XXXVIII. A Letter from Dr. Benjamin Franklin to Mr. AI- phonfus le Roy, Member of fever al Academies at Paris, con- taining fundry Maritime Obfervations, ■ 294 XXXIX. Account of two Hearts found in one Partridge, 33 XL. ConjeRures concerning Wind and Water Spouts, Tornados and Hurricanes. Communicated by Dr. Joha Perkins, of Beflon, to John Morgan, M. D. isc. ijc. 335 XLI. The -whole Proccfs of the Silk Worm, Jrom the Egg to the Cocon 1 communicated to Dr. John Morgan, ifc. at Philadel- phia, in tiuo Letters from Meffrs Hare and Skinner, ire. in London, July 27, 1774, and February 24, lyjSt 347 XLII. The Art of making Anatomical Preparations by Corrofion. By John Morgan, M. D. on an improved Sea-Compafs, 396 TRANS- TRANSACTIONS O F T H E American Philosophical Society, &c. N° I. A Letter from Dr. B. Franklin to Dr. Ingenhausz, Phyfician to the Emperor^ at Vienna. Dear Friend, id 2ift oa.-i78i At fea, Auguft aStli, 1785. Readjift T^N one of your letters, a little before I left France, you defire me to give you in writing -**" my thoughts upon the conftrudion and ufe of chimneys, a fubjedl you had fometimes heard me touch upon in converfation. I embrace willingly this leifurc afforded by my prefent fituation to comply with your re- quefl, as it will not only fhow my regard to the defires of a friend, but may at the fame time be of fome utility to others; the doiftrine of chimneys appearing not to be as yet generally well underftood, and miftakes refpeding them being attended with conflant inconvenience, if not remedied ; and with fruitlefs cxpence, if the true remedies are miflaken. Thofe who would be acquainted with this fubjed: fhould begin by confidering on what principle fmoke afcends in any chimney. At firft many are apt to think that fmoke is 2 LETTER CONCERNING is in its nature and of itfelf fpecifically lighter than air» and rifes in it for the fame reafon that cork rifes in water. Thefe fee no caufe why fmoke fhould not rife in the chim- ney, though the room be ever fo clofe. Others think there is a power in chimneys to draiv up the fmoke, and that there are different forms of chimneys which af- ford more or lefs of this power. Thefe amufe themfelves •with fearching for the bell form. The equal dimenfions of a funnel in its whole length is not thought artificial enough, and it is made, for fancied reafons, fometimes ta- pering and narrowing from below upwards, and fome- times the contrary, &c. &c. A fimple experiment or two may ferve to j2ive more corredt ideas. Having lit a pipe of tobacco, plunge the ftem to the bottom of a decanter half filled with cold water; then putting a rag over the bowl, blow through it and make the fmoke defcend in the ftem of the pipe, from the end of which it will rife in bubbles through the water ; and being thus cooled, will not afterwards rife to go out through the neck of the de- canter, but remain fpreading itfelf and reftlng on the fur- face of the water. This ihows that fmoke is really hea- vier than air, and that it is carried upwards only when at- tached to, or aded upon, by air that is heated, and there- by rarefied and rendered fpecifically lighter than the air ia its neighbourhood. Smoke being rarely feen but in company with heated air, and its upv/ard motion being vifible, though that of the rarefied air that drives it is not fo, has naturally given rife to the error. I need not explain to you, my learned friend, what is meant by rarefied air; but if you make the public uie you propofe of ihis letter, it may fall into the hands of fome who are unacquainted with the term and with the thing. Thefe then may be told, that air is a fluid which has weight as well as others, though about eight hundred times lighter than water. That heat makes the particles of air recede CHIMNEYS. 3 recede from each other and take up more fpace, fo that the fame weight of air heated will have more bulk, than equal weights of cold air which may furround it, and in that cafe muft rife, being forced upwards by fuch cold- er and heavier air, which prelTes to get under it and take its place. That air is fo rarefied or expanded by heat, may be proved to their comprehenfion by a lank blown bladder, which laid before a lire will foon fwell, prow ti$rht and burft. Another experiment may be to take a glafs tube about an inch in diameter, and twelve inches long, open at both ends and fixed upright on legs fo that it need not be han- dled, for the hands might warm it. At the end of a quill fallen five or fix inches of the fineft light filament of filk, fo that it may be held either above the upper end of the tube or under the lower end, your warm hand being at a diftance by the length of the quill. If there were Fi^ure''r. ^"7 motiou of air through the tube, it would ma- nifeft itfelf by hs efFeft on the filk ; but if the tube and the air in it are of the fame temperature with the fur- rounding air, there will be no fuch motion, whatever may be the form of the tube, whether crooked or ftrait, narrow below and widening upwards, or the contrary ; the air in it will be quiefcent. Warm the tube, and you will find as long as it continues warm, a conftant current of air enter- ing below and paffing up through it, till difcharged at the top; becaufe the warmth of the tube being communicated to the air it contains, rarefies that air and makes it lighter than the air without, which therefore prefles in below, forces it upwards, follows and takes its place, and is rare- fied in its turn. And, without warming the tube, if you hold under it a knob of hot iron, the air thereby heated will rife and fill the tube, going out at its top, and this motion in the tube will conLinuc as long as the knob remains hor, becauie the air entering the tube below is heated and ra- refied by paffing near and over that knob. That 4 LETTER CONCERNING That this motion is produced merely by the difference o^ fpccific gravity between the fluid within and that without the tube, and not by any fancied form of the tube itfelf, may appear by plunging it into water contained in a glafs jar a foot deep, through which fuch motion might be feen. The water within and without the tube being ot the fame fpeciHc gravity, balance each other, and both re- main at reit. But take out the tube, ftop its bottom with a finger and fill it with olive oil, which is lighter than water, then flopping the top, place it as before, its lower end under water, its top a very little above. As long as you keep the bottom ftopt, the fluids remain at reft, but the moment it is unftopt, the heavier enters below, forces up the lighter, and takes its place. And the motion then ceafes, merely becaufe the new fluid cannot be fucceffively made lighter, as air may be by a warm tul^e.- In fadl:, no form of the funnel of a chimney has any fhare in its operation or cffeO: refpetfling fmoke, except its height. The longer the funnel, if eredl, the greater its force when filled with heated and rarefied air, to draiv in below and drive up the fmoke, if one may, in compliance with cuftom, ufe the exprefllon draiu, when in fadl it is the fuperior weight of the furrounding atmofphere that prej/es to enter the funnel below, and fo dj-ives up before it the fmoke and warm air it meets with in its paflage. I have been the more particular in explaining thefe firfl: principles, becaufe, for want of clear ideas refpeding them, much fruitlefs expence has been occafioned ; not only fmgle chimneys, but in fome inflances, within my know- ledge, whole flacks having been pulled down and rebuilt with funnels of diff^erent forms, imagined more powerful in draivi7ig fmoke; but having flill the fame height and the fame opening below, have performed no better than their predecelTors. What is it then which makes zfmoky chimney-, that is, a chimney which infliead of conveying up all the fmoke, difcharges. CHIMNEYS. 5 difcliarges a part of it into the room, offending the eyes "and damaging the furniture ? The caufes of this effefl:, which have fallen under my obfervation, amount to nine, diifering from each other, and therefore requiring different remedies. I. Smokj chimneys in a iieiv houfe, are fuch, frequently from mtre tvant of air. The workmanfhip of the rooms being all good, and juft out of the workm.an's hand, the joints of the boards of the flooring, and of the pannels of wainfcotting are all true and tight, the more fo as the walls, perhaps not yet thoroughly dry, preferve a damp- nels in the air of the room which keeps the wood-work fwelled and clofe. The doors and the fafhes too, being worked with truth, fhut with exaclnefs, fo that the room is as tight as a fnuff-box, no paffage being left open for air to enter, except the key-hole, and even that is fome- times covered by a little dropping fhutter. Now if fmoke cannot rife but as connefted with rarefied air, and a column of fuch air, fuppofe it filling the funnel, cannot rife, unlefs other air be admitted to fupply its place ; and if, therefore, no current of air enter the opening of the chimney, there is nothing to prevent the fmoke coming out into the room. If the motion upwards of the air in a chimney that is freely fupplied, be obferved by the rifing of the fmoke or a feather in it, and it be confidered that in the time fuch feather takes in rifing from the fire to the top of the chimney, a column of air equal to the content of the fun- nel muft be difcharged, and an equal quantity fupplied from the room below, it will appear abfolutely impoffible ^ that this operation lliould go on if the tight room is kept * fliut ; for were there any force capable of drawing con- ftantly fo much air out of it, it muft foon be exhauiled like the receiver ot an air pump, and no animal could live in it. Thofe therefore who flop every crevice in a room to prevent the admiffion of frelh air, and yet would have their chimney carry up the imoke, require inccnfiftencies, and 6 LETTER concerning end exped impofiibllities. Yet under this fituatlon, I have feen the owner of a new hoiife, in defpair, and ready- to fell it for much lefs than it coft, conceiving it unin- habitable, becaufe not a chimney in any one of its rooms would carry off the fmoke, unlefs a door or window w^ere left open. Much expence has alfo been made, to alter and amend new chimneys which had really no fault ; in one houfe particularly that I knew, of a nobleman in Weftminfter, that expence amounted to no Icfs than three hundred pounds, after his houfe had been, as he thought, finifhed and all charges paid. And after all, feveral of the alterations were ineffectual, for want of underftanding the true principles. Remedies. When you find on trial, that opening the door or a window, enables the chimney to carry up all the fmoke, you may be fure that want of a\v froin ivith^ out-, was the caufe of its fmoking. I fay from iv'ithoiitt to guard you againff a common miflake of thofe who may tell you, the room is large, contains abundance of air, fufficient to fupply any chimney, and therefore it cannot be that the chimney wants air. Thefe reafoners are igno- rant, that the largenefs of a room, if tight, is in this cafe of fmall importance, fmce it cannot part with a chimney full of its air without occafioning fo much vacuum ; which it requires a great force to effeifl, and could not be borne if effeded. It appearing plainly, then, that fome of the outward air muft be admitted, the queftion will be, how much is ahfolutely necefdry ; for you would avoid admitting more, as bein-'; contrary to one of your intentions in having a fire, viz. that of warming your room. To difcover this quantity, fliut the door gradually while a middling fire is burning, till you find that, before it is quite flint, the fmoke begins to come out into the room, then open it a little till you perceive the fmoke comes out no longer. There hold the door, and obferve the width of the open crevice be- tween CHIMNEYS. 7 tween the edge of the door and the rabbit It fhould {hut into. Suppole the diftance to be half an inch, and the door eight feet high, you find thence that your room re- quires an entrance for air equal in area to ninety fix half Inches, or forty eight fquare inches, or a paffage of fix inches by eight. This however is a large fuppofition, there being few chimneys, that, having a moderate open- ing and a tolerable height of funnel, will not be fatisfied. ■with fuch a crevice of a quarter of an inch ; and I have found a fquare of fix by fix, or thirty fix fquare inches, to be a pretty good medium, that will ferve for moft chimneys. High funnels with fmall and low openings^ may indeed be fupplied through a lefs fpace, becaufe, for reafons that will appear hereafter, the force of levity-, if one may fo fpeak, being greater in fuch funnels, the cool air enters the room with greater velocity, and confequent- ly more enters in the fame time. This however has its limits, for experience fhows that no increafed velocity fa occafioned, has made the admifhon of air through the key-hole equal in quantity to that through an open door; though through the door the current moves flowly, and through the key-hole with great rapidity. It remains then to be confidered how and where this neceifary quantity of air from without is to be admitted fo as to be leaft inconvenient. For, if at the door, left fo much open, the air thence proceeds diredly to the chimney, and in its way comes cold to your back and heels as you fit before your fire. If you keep the door fhut, and raife a little the laih of your window, you feel the fame incon- venience. Various have been the contrivances to avoid this, fuch as bringing in frefh air through pipes in the jams of the chimney, which pointing upwards Ihould blow the fmoke up the funnel ; opening pail'ages into the fun- nel above, to let in air for the fame purpofe. But thefe produce an effcd; contrary to that intended : For as it is the conftant current of air paffing from, the room through tha 8 LETTER concerning the opening of the chimney into the funnel which prevents the fmoke coming out into the room, if you fupply the funnel hy other means or in other ways with the air it wants, and efpecially if that air be cold, you diminifh the force of that current, and the fmoke in its efforts to enter the room finds lefs refiftance. The wanted air lYiuft then indifpenfably be admitted into the room, to fupply what goes off through the opening of the chimney. M, Ganger, a very ingenious and in- telligent French writer on the fubjed:, propofes with judgment to admit it above the opening of the chimney ; and to prevent inconvenience from its coldnefs, he direfts its being made to pafs in its entrance through winding cavities made behind the iron back and fides of the fire- place, and under the iron hearth-plate ; in which cavities it wmU be warmed, and even heated, fo as to contribute much, inftead of cooling, to the warming of the room. This invention is excellent in itfelf, and may be ufed with advantage in building new houfes ; becaufe the chimneys may then be fo difpofed, as to admit conveniently the cold air to enter fuch paffages : But in houfes built without fuch views, the chimneys are often fo fituated, as not to afford that convenience, without great and expenfive al- terations. Eafy and cheap methods, though not quite fo perfedt in themfelves, are of more general utility ; and fuch are the following. In all rooms where there is a fire, the body of air warm- ed and rarefied before the chimney is continually changing place, and making room for other air that is to be warm- ed in its turn. Part of it enters and goes up the chimney, and the reft rifes and takes place near the ceiling. If the room be lofty, that warm air remains above our heads as long as it continues warm, and we are little benefited by it, becaufe it does not defcend till it is cooler. Few can imagine the difference of climate between the upper and lower parts of fuch a room, who have not tried it by the thermometer, CHIMNEYS. 9 thermometer, or by going up a ladder till their heads are near the ceiling. It is then among this warm air that the wanted quantity of outward air is beft admitted, with which being mixed, its coldnefs is abated, and its incon- venience diminifhed fo as to become fcarce obfervable. This may be eafily done, by drawing down about an inch the upper lafh of a window ; or, if not moveable, by cut- ting fuch a crevice through its frame ; in both which cafes, it will be w-ell to place a thin fhelf of the length, to con- ceal the opening, and floping upwards to direct the enter- ing air horizontally along and under the ceiling. In fome houfes the air may be admitted by fuch a crevice made in the wainfcot, cornifli or plaftering, near the ceiling and over the opening of the chimney. This, if praflicablc, is to be chofen, becaufe the entering cold air wnll there meet with the warmeft rifing air from before the fire, and be fooneft tempered by the mixture. The fame kind of Ihelf fhould alfo be placed here. Another way, and not a very difficult one, is to take out an upper pane of glafs in one of your fafhes, fet it in a tin frame, giving it two fpringing angular fides, and then replacing p^l%^\ it, with hinges below on which it may be turned to open more or lefs above. It will then have the ap- pearance of an internal flcy light. By drawing this pane in, more or lefs, you may admit what air you find necef- fary. Its pofition will naturally throw that air up and along the ceiling. This is what is called in France a IVas iji das ? As this is a German queftion, the invention is probably of that nation, and takes its name from the fre- quent afking of that queftion when it firft appeared. In England, fome have of late years cut a round hole about five inches diameter in a pane of the falh and placed againft: it a circular plate of tin hung on an axis, and cut into vanes, which being feparately bent a little obliquely, arc a£led upon by the entering air, fo as to force the plate con- tinually round like the vanes of a windmill. This ad- B mits lO LETTER CONCERNING xnits the outward air, and by the continual whirling of the vanes, does in fome degree difperfe it. The noife only, is a little inconvenient. 2. A fecond caufe of the finoking of chimneys is, their openings in the room being too large ; that is, too wide, too high or both. Architedls in general have no other ideas of proportion in the opening of a chimney, than what relate to fymmetry and beauty, refpedting the dimenfions of the room* ; while its true proportion, refpe(5ling its funftion and utility depends on quite other principles ; and they might as properly proportion the ftep in a ftair- cafe to the height of the ftory, inflead of the natural ele- vation of men's legs in mounting. The proportion then to be regarded, is what relates to the height of the funnel. For as the funnels in the different ftories of a houfe are neceffarily of different heights or lengths, that from the loweft floor being the higheft or longeft, and thofe of the other floors fhorter and fhorter, till we come to thofe in the garrets, which are of courfe the fliorteft ; and the force of draft being, as already faid, in proportion to the height of funnel filled with rarefied air; and a current of air from the room into the chimney, fufficient to fill the opening, being neceffary to oppofe and prevent the fmoke coming out into the room ; it follows that the openings of the longeft funnels may be larger, and that thofe of the fhorter funnels fhould be fmaller. For if there be a large open- ing to a chimney that does not draw ftrongly, the funnel may happen to be furnlfhed with the air it demands by a partial current entering on one Cde of the opening, and leaving the other fide free of any oppofing current, may permit the fmoke to iffue there into the room. Much too of the force of draft in a funnel depends on the degree of rarefaftion in the air it contains, and that depends on the nearnefs to the fire of its pafTage in entering the funnel. If it can enter far from the fire on each fide, or far above the fire, in a wide or high opening, it receives little heat ia * See Appendix, K ° I. CHIMNEYS. ti in pafling by the fire, and the contents of the funnel is by that means lefs different in levity from the furrounding atmofphere, and its force in drawing confequently weaker. Hence it too large an opening be given to chimneys in upper rooms, thofe rooms will be fmoky : On the other hand, if too fmall openings be given to chimneys in the lower rooms, the entering air operating too diredlly and violently on the fire, and afterwards ftrengthening the draft as it afcends the funnel, will confume the fuel too rapidly. Remedy. As different clrcumftances frequently mix themfelves in thefe matters, it is difficult to give precifc dimenfions foi the openings of all chimneys. Our fathers made them generally much too large ; we have leffened them; but they are often ftlU of greater dimenfion than they fhould be, the human eye not being eafily reconciled to fudden and great changes. If you fufpedl that your chimney fmokes from the too great dimenfion of its open- ing, contrail it by placing moveable boards fo as to lower and narrow it gradually, till you find the fmoke no longer iffues into the room. The proportion fo found will be that which is proper for that chimney, and you may employ the bricklayer or mafon to reduce it accordingly. However, as, in building new houfes, fomething mufl: be fometimes hazarded, I would make the openings in my lower rooms about thirty inches fquare and eighteen deep, and thofe in the upper, only eighteen inches fquare and not quite fo deep ; the intermediate ones dimlnilhing in proportion as the height of funnel diminhhed. In the larger openings, billets of two feet long, or half the common length of cord- wood, may be burnt conveniently ; and for the fmaller, fuch wood may be fawed into thirds. Where coals are the fuel, the grates will be proportioned to the openings. The fame depth is nearly neceffary to all, the funnels be- ing all made of a fize proper to admit a chimney-fweeper. If in large and elegant rooms cuftom or fancy fhould re- B s quire 12 LETTER CONCERNING quire the appearance of a larger chimney, it may be form- ed of expenfive marginal decorations, in marble, &c. la time perhaps that which is fitteft in the nature of things, may come to be thought handfomeft. But at prefent when men and women in different countries fhow themfelves diffatisfied with the forms God has given to their heads, waifts and feet, and pretend to fliape them more perfect- ly, it is hardly to be expeded that they will be content always with the beft form of a chimney. And there are fome I know fo bigotted to the fancy of a large noble opening, that rather than change it, they would fubmit to have damaged furniture, fore eyes and fkins almofl fraoked to bacon. 3. Another caufe of fmoky chimneys is, too /hort afiin-' nel. This happens neceflarily in fome cafes, as where a chimney is required in a low building ; for, if the fun- nel be raifed high above the roof, in order to ftrengthen its draft, it is then in danger of being blown down, and crulhing the roof in its fall. Remedies. Contrad: the opening of the chimney, fo as to oblige all the entering air to pafs through or very near the fire; whereby it will be more heated and rarefied, the funnel Itfelf be more warmed, and its contents have more of what may be called the force of levity, fo as to rife ftrongly and maintain a good draft at the opening. Or you may in fome cafes, to advantage, build additi- onal flories over the low building, which will fupport a high funnel. If the low building be ufed as a kitchen, and a contrac- tion of the opening therefore inconvenient, a large one be- ing neceffary, at leaft when there are great dinners, for the free management of fo many cooking utenfils ;*in fuch cafe I would advife the building of two more funnels join- ing to the htfl, and having three moderate openings, one to each funnel, inftead of one large one. When there is occafion to ufe but one, the other two may be kept Ihut by CHIMNEYS. '3 by flidlng plates, hereafter to be defcribed*; and two or all of them may be ufed together when wanted. This will indeed be an expence, but not an ufelefs one, fince your cooks will work with more comfort, fee better than in a fmoky kitchen what they are about, your victuals will be cleaner drefled and not tafte of fmoke, as is often the cafe ; and to render the effeft more certain, a ftack of three fun- nels may be fafely built higher above the roof than a lin- gle funnel. The cafe of too fliort a funnel is more general than would be imagined, and often found where one would not expedt It. For it is not uncommon, in ill-contrived build- ings, inftead of having a funnel for each room or hreplace, to bend and turn the funnel of an upper room fo as to make it enter the fide of another funnel that comes from below. By this means the upper room funnel is made fhort of courfe, fmce its length can only be reckoned from the place where it enters the lower room funnel; and that funnel is alfo Ihortencd by all the diftancc between the en- trance of the fecond funnel and the top of the ftack: For all that part being readily fupplied with air through the fecond funnel, adds no ftrength to the draft, efpecially as that air is cold when there is no fire in the fecond chim- ney. The only eafy remedy here is, to keep the open- ing fhut of that funnel in which there is no fire. 4. Another very common caufe of the fmoking of chimneys; is, their Gverpozvering one another. F"or in- ftance, it there be two chimneys in one large room, and you make fires in both of them, the doors and windows clofe fhut, you will find that the greater and ftronger fire fhall overpower the weaker, and draw air down its funnel to lupply its own demand; which air defcending in the weaker funnel will drive down its fmoke, and force it into the room. It, inftead of being in one room, the two chim- neys are in two dift"erent rooms, communicating by a door, the cafe is the fame whenever that door is open. In a very ti^ht ' See Appendix, N o II. 14 LETTER concerning tight houfe, I have known a kitchen chimney on the low- eft floor, when it had a great fire in it, overpower any other chimney in the houfe, and draw air and Imoke into its room, as often as the door was opened communicating •with the ftaircafe. Remedy. Take care that every room have the means of fupplying itfelf from without, with the air its chimney may require, lb that no one of them may be obliged to borrow from another, nor under the neceflity of lending. A variety of thefe means have been already defcribed. 5. Another caufeof fmoking is, ivhen the tops of chm- neys are commanded by higher buildings, or by a hill-, fo that the wind blowing over fuch eminences falls like water over a dam, fometimes almoft perpendicularly on the tops of the chimneys that lie in its way, and beats down the fmoke contained in them. Remedy. That commonly applied to this cafe, Is a turncap made of tin or plate iron, covering the chimney above and on three fides, open on one fide, turning on a fpindle, and which being guided or governed by a vane, always prefents its back to the current. This I believe may be generally efFe£tual, though not certain, as there may be cafes in which it will not fucceed. Railing your funnels if pradlicable, fo as their tops may be higher, or at leaft equal with the commanding eminence, is more to be de- pended on. But the turning cap, being eafier and cheaper, ihould firft be tried. If obliged to build In fuch a fituatlon, I would chufe to place my doors on the fide next the hill, and the backs of my chimneys on the furtheft fide; for then the column of air falling over the eminence, and of courfe prefling on that below and forcing It to enter the doors, or M^as-ijl-dases on that fide, would tend to balance the prefTure down the chimneys, and leave the funnels more free In the exercife of their fundtions. 6. There Is another cafe of command, the reverfe of that laft mentioned. It Is where the commanding emi- nence CHIMNEYS. 15, nence is farther from the wind than the chimney com- manded. To explain this a figure may be neceffary, Suppofe then a building whofe fide A, happens to be expof- ed to the wind, and forms a kind of dam againft its proerefs. The air obftrudted by this dam will like l^!'^" '• water prefs and fearch for paflages through it ; and finding the top of the chimney B, below the top of the dam, it will force itfelf down that funnel, in order to get through by fome door or window open on the other fide of the building. And if there be a fire in fuch chimney, its fmoke is of courfe beat down, and fills the room. Remedy. I know of but one, which is to raife fuch funnel higher than the roof, fiapporting it, ifneceffary, by iron bars. For a turn-cap in this cafe has no effeft, the dammed up air preffmg down through it in whatever po- fition the wind may have placed its opening. I know a city in which many houfes are rendered fmoky by this operation. For their kitchens being built behind, and connected by a paflage with the houfes, and the tops of the kitchen chimneys lower than the top of the houfes, the whole fide of a llreet when the wind blows againft its back, forms fuch a dam as above defcribed ; and the wind fo obftruded forces down thofe kitchen chimneys, (efpe- cially when they have but weak fires in them) to pafs through the pafl'age and houfe, into the ftreet. Kitchen chimneys fo formed and fituated, have another inconve- nience. In fummer, if you open your upper room wind- dows for air, a light breeze blowing over your kitchen chimney towards the houfe, though not ftrong enough to force down its fmoke as aforefaid, is fufficient to waft it into your windows, and fill the rooms with it; which, be- tides the difagreeablenefs, damages your furniture. 7. Chimneys, otherwife drawing well, are fometimes made to fmoke by the improper and incowvenient fituat'wn of a door. When the door and chimney are on the fame fide of the room as in the figure, if the door A, being in the- /, i6 LETTER concerning the corner Is made to open againft the wall, which pi;uc I. jg common, as bcino: there, when open, more out of the way, it follows, that when the door is on- ly opened in part, a current of air rufhing in paffes along the wall into and acrofs the opening of the chimney B, and flirts fome of the fmoke out into the room. This happens more certainly when the door is fhutting, for then the force of the current is augmented, and becomes very inconvenient to thofe who, warming themfelves by the fire, happen to fit in its way. The Remedies are obvious and eafy. Either put an in- tervening flcreen from the wall round great part of the fire- place ; or, which is perhaps preferable, fliift the hinges of your door, fo as it may open the other way, and when open throw the air along the other wall. 8. A room that has no fire in its chimney, is fome- times filled with fmoke ivhich zs I'ecei'ued at the top of its ftimiel and defcends into the room. In a former paper* I have already explained the defcending currents of air in cold funnels; it may not be amifs however to repeat here, that funnels without fires have an effedt according to their degree of coldnefs or warmth, on the air that happens to be contained in them. The furround- ing atmofphere is frequently changing its temperature ; but flacks of funnels covered from winds and fun by the houfe that contains them, retain a more equal temperature. If, after a warm feafon, the outward air fuddenly grows cold, the empty warm funnels begin to draw ftrongly up- ward ; that is, they rarefy the air contained in them, which of courfe rifes, cooler air enters below to fupply its place, is rarefied in its turn and rifes ; and this operation conti- nues, till the funnel grows cooler, or the outward air warmer, or both, when the motion ceafes. On the other hand, if after a cold feafon, the outward air fuddenly grows warm and of courfe lighter, the air contained in the cool funnels, being heavier, defcends into the room ; and the warmer « Sec AiJpendix, N° 11. CHIMNEYS. 17 warmer air which enters their tops hc'inq cooled in its turn, and made heavier, continues to defeend ; aid this operation goes on, till the funnels are warmed hy the paf- fing of warm air through them, or the air iticlf grows cooler. When the temperature of the air and of the fun- nels is nearly equal, the difference of warmth in the air between day and night is fufHcient to produce thefe cur- rents, the air will begin to afcend the funnels as the cool of the evening comes on, and this current will continue till perhaps nine or ten o'clock the next morning, when it begins to hefitate ; and as the heat of the day approach- es, it fets downwards, and continues fo till towards even- ing, when it again hefitates for fome time, and then goes upwards conftantly during the night, as before mentioned. Now when fmoke iffuing froni the tops of neighbouring funnels paffes over the tops of funnels which are at the time drawing downwards, as they often are in the middle part of the day, fuch fmoke is of neceffity drawn into thefe funnels, and defcends with the air into the chamber. The Remedy is to have a Aiding plate, hereafter de- fcribed*, that will fhut perfedlly the offending funnel. 9. Chimneys which generally draw well, do neverthe- lefs fometimes give fmoke into the rooms, it being driveit doijon by Jirong ivinds pajjtng over the tops of their funnels^ though not defcending from any commanding eminence. This cafe is moft frequent where the funnel is fhort, and the opening turned from the wind. It is the more griev- ous, when it happens to be a cold wind that produces the effect, becaufe when you moft want your fire, you are fometimes obliged to extinguifh it. To underftand this, it may be confidered that the rifmg light air, to obtain a free Iflue from the funnel, muft pufh out of its way or oblige the air that is over it to rife. In a time of calm or of little wind this is done vifibly, for we fee the fmoke that is brought up by that air rife in a column above the chimney. But when a violent current of air, that is, a C fir on g '■ Sec Appendii:, N° 11. i8 LETTER concerning ftrong wind, pafTes over the top of a chimney, its particles have received fo much force, which keeps them in a hori- zontal diredion and follow each other fo rapidly, that the rifing light air has not ftrength fufficient to oblige them to quit that direction and move upwards to permit its ilTue. Add to this, that fome of the current paffmg over that fide of the funnel which it firft meets with, viz. at A, Fi'^urJv having been comprefled by the refiftance of the funnel, may expand itfclf over the flue, and ftrike the interior oppofite fide at B, from whence it may be re- fledled downwards and from fide to fide in the diredlion of the pricked lines c c c. Remedies. In fome places, partic-ularly in Venice, where they have not flacks of chimneys but fingle flues, the cuf- tom is, to open or widen the top of the flue round- f' we'"6 ^"S iri the true form of a funnel ; which fome think may prevent the effe£l jufl; mentioned, for that the wind blowing over one of the edges into the funnel may be flanted out again on the other fide by its form. I have had no experience of this ; but I have lived in a windy country, where the contrary is pradifed, the tops of the flues being narroived inwards, fo as to form a flit for the iflue of the fmoke, long as the breadth of the funnel, and only four inches w^ide. This feems to have been contrived on a fuppofition that the entry of the wind would thereby be obftruded, and perhaps it might have been imagined, that the whole force of the rifing warm air being con- denfed, as it were, in the narrow opening, would thereby be ftrengthened, fo as to overcome the refiftance of the wind. This however did not always fucceed ; for when the wind was at north-eaft and blew frefli, the fmoke was forced down by fits into the room I commonly fat in, fo as to oblige me to fliift the fire into another. The pofition of the flit of this funnel was indeed north-eaft and fouth- weft. Perhaps if it had lain acrofs the wind, the eff"ed: might have been different. But on this I can give no cer- tainty. CHIMNEYS. T9 tainty. It feems a matter proper to be referred to experi- ment. Poflibly a turn-cap might have been ferviocable, but it was not tried. Chimneys have not been long in ufe in England. I for- merly faw a book printed in the time of queen Elizabeth, •which remarked the then modern improvements of living, and mentioned among others the convenience of chimneys. " Our forefathers," faid the author, " had no chimneys. " There was in each dwelling houfe only one place for a " fire, and the fmoke went out through a hole in the *' roof; but now there is fcarce a gentleman's houfe in " England that has not at leaft one chimney in it." — When there was but one chimney, its top might then be opened as a funnel, and perhaps, borrowing the form from the Venetians, it was then the flue of a chimney got that name. Such is now the growth of luxury, that in both England and France we muft have a chimney for every room, and in fome houfes every pofleflbr of a chamber, and almoft every fervant, will have a fire ; fo that the flues being neceflarily built in flacks, the opening of each as a funnel is impracticable. This change of manners foon confumed the firewood of England, and will foon render fuel extremely fcarce and dear in France, if the ufe of coals be not introduced in the latter, kingdom as it has been in the former, where it at firft met with oppofition ; for there is extant in the records of one of queen Elizabeth's parliaments, a motion made by a member, reciting, " that " many dyers, brewers, fmiths, and other artificers of Lon- " don, had of late taken to the ufe of pitcoal for their fires, " inftead of wood, which filled the air with noxious va- *' pours and fmoke, very prejudicial to the health, parti- *' cularly of perfons coming out of the country ; and there- " fore moving that a law might pafs to prohibit the ufe *' of fuch fuel (at leaft during the feflion of parliament) " by thofe artificers." — It feems it was not then common- ly ufcd in private houfes. Its fuppofed uuMdioIefomenefs C 2 was 20 ^ LETTER CONCERNING was an objeilion. Luckily the inhabitants of London have got over that objeftion, and now think it rather con- tributes to render their air falubrious, as they have had no general peflilential diforder fince the general ule of coals, when, before it, fuch were frequent. Paris ftill burns wood at an enormous expence continually augmenting, the in- habitants having ftill that prejudice to overcome. In Ger- many you are happy in the ufe of ftoves, which fave fuel wonderfully : Your people are very ingenious in the ma- nagement of fire ; but they may ftill learn fomething in that art from the Chinefe*, whofe country being greatly- populous and fully cultivated, has little room left for the growth of wood, and having not much other fuel that is good, have been forced upon many inventions during a courfe of ages, for making a little fire go as far as poffible. I have thus gone through all the common caufes of the fmoking of chimneys that I can at prefent recolledt as hav- ing fallen under my obfervation ; communicating the re- medies that I have known fuccefsfully ufed for the differ- ent cafes, together with the principles on which both the difeafe and the remedy depend, and confeffing my igno- rance wherever I have been fenfible of it. You will do •well, if you publifti, as you propofe, this letter, to add in notes, or as you pkafe, fuch obfervations as may have oc- curred to your attentive mind ; and if other philofophers will do the fame, this part of fclence, though humble, yet of great utility, may in time be perfedled. For many years paft, I have rarely met with a cafe of a fmoky chimney, which has not been folvable on thefe principles, and cured by thefe remedies, where people have been willing to ap- ply them ; which is indeed not always the cafe ; for many have prejudices in favour of the noftrums of pretending chimney-dodtors and fumifts, and fome have conceits and' fancies of their own, which they rather chufe to try, than to lengthen a funnel, alter the fize of an openinp;, or ad- mit air into a room, however neceffary j for fome are as much * Sec Appendix, N° III. CHIMNEY S. 21 much afraid of frefh air as perfons in the hydrophobia are of frefh water. I myfelf had formerly this prejudice, this aerophobia^ as I now account it, and dreading the fuppofed dangerous efFefts of cool air, I confidcrcd it as an enemy, and doled with extreme care every crevice in the rooms I inhabited. Experience has convinced me of my error. I now look upon frefh air as a friend : I even fleep with an open window. I am perfuaded that no common air from •without, is fo unwholefome as the air within a clofe room that has been often breathed and not changed. Moid air too, which formerly I thought pernicious, gives me now no apprehenfions : For coniidering that no dampnefs of air applied to the outfide of my ikin, can be equal to what is applied to and touches it within, my whole body being full of moiflure, and finding that I can lie two hours in a bath twice a week, covered with water, which certainly is much damper than any air can be, and this for years together, without catching cold, or being in any other man- ner difordered by it, I no longer dread mere moifture, either in air or in fheets or fliirts: And I find it of importance to the happinefs of life, the being freed from vain terrors, efpecially of objedls that we are every day expofed in- evitably to meet with. You phyficians have of late hap- pily difcovered, after a contrary opinion had prevailed fome ages, that frefh and cool air does good to perfons in the fmall pox and other fevers. It is to be hoped that in another century or two we may all find out, that it is not bad even for people in health. And as to moifi: air, here I am at this prefent writing in a fhip with above forty perfons, who have had no other but moifl: air to breathe for fix weeks pafl ; every thing" we touch is damp, and nothing dries, yet we are all as healthy as we fliould be on the mountains of Switzerland, whofe inhabitants are not more fo than thofe of Bermuda or St. Helena, ifiands on whofe rocks the waves are dafhed into millions of par- ticles, which fill the air with damp, but produce no dif- eales 22 LETTER CONCERNING eafes, the moifture being pure, unmixed with the poifon- ous vapours arifing from putrid marfhes and ftagnant pools, in which many infedls die and corrupt the water. Thefe places only, in my opinion, (which however I fub- mit to yours) afFord unwholefome air ; and that it is not the mere water contained in damp air, but the volatile particles of corrupted animal matter mixed with that wa- ter, which renders fuch air pernicious to thofe who breathe it. And I imagine it a caufe of the fame kind that ren- ders the air in clofe rooms, where the perfpirable matter is breathed over and over again by a number of affembled people, fo hurtful to health. After being in fuch a fitua- tion, many find themfelves afFe(3:ed by that febricida., which the Englifli alone call a cold^ and, perhaps from the name, imagine that they caught the malady by going out of the room, when it was in fadl by being in it. You begin to think that I wander from my fubjed, and go out of my depth. So I return again to my chimnevs. We have of late many lecturers in experimental philo- fophy. I have wiilied that fome of them would ftudy this branch of that fcience, and give experiments in it as a part of their letlures. The addition to their prefent apparatus need not be very expeniive." A number of little reprefen- tations of rooms compofed each of five panes of fafh glafs, framed in wood at the corners, with proportionable doors, and moveable glafs chimneys, with openings of different fizes, and different lengths of funnel, and fome of the rooms fo contrived as to communicate on occafion with others, fo as to form different combinations, and exem- plify different cafes ; with quantities of green wax taper cut into pieces of an inch and ha f, fixteen of which fluck together in a fquare, and lit, would make a ftrong fire for a little glafs chimney, and blown out would continue to burn and give fmoke as long as defired. With fuch an apparatus all the operations of fmoke and rarefied air in rooms and chimneys might be feen through their tranfpa- rent CHIMNEYS. 23 rent fides; and the effcd of winds on chimneys, com- manded or otherwife, might be fhown by Icttina; the ca- tering air blow upon them through an opened window of the lecturer's chamber, where it would be conftant while he kept a good fire in his chimney. By the help of fuch Icdures our fumifts would become better inftruded. At prefent they have generally but one remedy, which per- haps they have known effectual in Ibme one cafe of fmoky chimneys, and they apply that indifcriminately to all the other cafes, without fuccefs, — but not without expence to their employers. With all the fcience, however, that a man fliall fuppofe himfelf poiTefled of in this article, he may fometimes meet with cafes that Ihall puzzle him. I once lodged in a houfe at London, which, in a little room, had a fingle chimney and funnel. The opening was very fmall, yet it did not keep in the fmoke, and all attempts to have a fire in this room were fruitlefs. I could not imagine the reafon, till at length obferving that the chamber over it, which had no fire-place in it, was always filled with fmoke when a fire was kindled below, and that the fmoke came through ;the cracks and crevices of the wainfcot ; I had the wainfcot taken down, and difcovered that the funnel which went up behind it, had a crack many feet in length, and wide enough to admit my arm, a breach very dangerous with regard to fire, and occafioned probably by an apparent ir- regular fettling of one fide of the houfc. The air enter- ing this breach freely, dertroyed the drawing force of the funnel. The remedy v/ould have been, filling up the breach or rather rebuilding the funne! : But the landlord rather chofe to flop up the chimney. Another puzzling cafe I met with at a friend's country houfe near London. His befl: room had a chimney in •which, he told me, he never could have a fire, for all the fmoke came out into the room. I flattered mvfelf I could, eafily find the caufe, and prefcribe the cure. I had a fire made.^ 24 LETTER concerning made there, and found it as he faid. I opened the door, and perceived it was not want of air. I made a temporary contradlion of the opening of the chimney, and found that it was not its being too large that caufed the fmoke to iifue. I went out and looked up at the top of the chimney : Its funnel was joined in the fame ftack with others, fome of them fhorter, that drew very well, and I faw nothing to prevent its doing the fame. In fine, after every other ex- amination I could think of, I was obliged to own the in- fufficiency of my fkill. But my friend, who made no pretenfion to fuch kind of knowledge, afterwards difco- vered the caufe himfelf. He got to the top of the funnel by a ladder, and looking down, found it filled with twiggs and ftraw cemented by earth, and lined with feathers. It feems the houfe, after being built, had flood empty fome years before he occupied it ; and he concluded that fome large birds had taken the advantage of its retired fituation to make their neft there. The rubbifli, confiderable in quantity, being removed, and the funnel cleared, the chimney drew well, and gave fatisfaftion. In general, fmoke is a very tradable thing, eafily go- verned and directed when one knows the principles, and is well informed of the circumftances. You know I made it defcend in my Pennfylvania ftove. I formerly had a more fvmple conftrudlion, in which the fame effe£t was produced, but vifible to the eye. It was compof- piatc I. pj Qf j^^,Q plates A B and C D, placed as in the figure. The lower plate A B refted with its edge in the angle made by the hearth v.'ith the back of the chimney. The upper plate was fixed to the breaft, and lapt over the lower about fix Inches, leaving a fpace of four inches wide and the length of the plates (near two feet) between them. Every other pafTage of air into the funnel was well flopped. When therefore a fire was made at E, for the firft time with charcoal, till the air in the lunnel was a little heated through the plates, and then wood CHIMNEYS. 25 wood laid on, the fmoke would rife to A, turn over the edge of that plate, defcend to D, then turn under the edge of the upper plate, and go up the chimney. It was pretty to fee, but of no great ufe. Placing therefore the under plate in a higher fituation, 1 removed the upper plate C D, and placed it perpendicularly, fo that pji^^A the upper edge of the lower plate A B came with- in about three inches of it, and might be pufhed farther from it, or fufFercd to come nearer to it by a moveable wedge between them. The Hame then afccnding from the fire at E, was carried to ftrike the upper plate, made it very hot, and its heat rofe and fpread with the rarefied air into the room. I believe you have feen in ufe with me, the contrivance of a fliding-plate over the fire, feemingly placed to oppofe the rifing of the fmoke, leaving but a finall paffage for it, between the edge of the plate and the back of the chimney. It is particularly defcribed, and its ufes explained, in my former printed letter, and I mention it here only as ano- ther inftance of the tra£tability of fmoke*. What is called the Staffordihire chimney, affords an ex- ample of the fame. kind. The opening of the chimney is bricked up, even with the fore-edge of its jams, leaving open only a paffage over the grate of the fame width, and perhaps eight inches high. The grate confifts of femicir- cular bars, their upper bar of the greatefi: diameter, the others under it fmaller and fmaller, fo that it has the ap- pearance of half a round bafket. It is, with the coals it contains, wholly without the wall that fhuts up the chim- ney, yet the fmoke bends and enters the paflage above it, the draft being ffrong, becaufe no air can enter that is not obliged to pafs near or through the fire, fo that all that the funnel is filled with is much heated, and of courfe much rarefied. D Much ■» See Appendix, N o II. 2-6. LETTER CONCERNIN( STAFFORDSHIRE FIRE-PLACE. SIDE VIEW. FRONT VIEW. Much more of the profperity of a winter country de- pends on the plenty and cheapnefs of fuel, than is gene- rally imagined. In travelling I have obferved, that in thofe parts where the inhabitants can have neither wood nor coal nor turfF bat at exceflive prices, the working peo- ple live in miferable hovels, are ragged, and have nothing comfortable about them. But where fuel is cheap, (or where they have the art of managing it to advantage) they are well furniihed with necelTaries, and have decent habi- tations. The obvious reafon is, that the working hours of fuch people are the profitable hours, and they who can- not afford fufficient fuel have fewer fuch hours in the twenty four, than thofe who have it cheap and plenty : For much of the domeftic work of poor women, fuch as fpinning, CHIMNEYS. 27 fplnning, fewing, knitting; ; and of the men in thofe ma- nufactures that require little bodily exercife, cannot well be performed where the fingers are numbed with cold : Thofe people, therefore, in cold weather, are induced to go to bed fooner, and b'e longer in a morning, than they w^ould do if they could have good fires or warm ftoves to fit by ; and their hours of work are not fufficient to pro- duce the means of comfortable fubfiftence. Thofe pub- lic works, therefore, fuch as roads, canals, &c. by which fuel may be brought cheap into fuch countries from diliant places, are of great utility ; and thofe who promote them may be reckoned among the benefadtors of mankind. I have great pleafure in having thus complied with your requeft, and in the reflection that the friendfhip you ho- nour me with, and in which I have ever been fo happy, has continued fo many years without the fmallefl: inter- ruption. Our diftance from each other is now augment- ed, and nature muft foon put an end to the pofhbility of my continuing our correfpondence : But if confciouihefs and memory remain in a future ftate, my efteem and re- fpeCl for you, my dear friend, will be everlafting. B. F. D 2 APPENDIX. APPENDIX. NOTES roR the LETTER upon CHIMNEYS. N° I. • ""FHE lateR- work on architecture that I have feen, is that entitled Nutshells, which appears to he written by a very Ingenious man, and contains a table of the propor- tions of the openings of chimneys ; but they relate folely to the proportions he gives his rooms, without the fmall- eft regard to the funnels. And he remarks, refpe£ting thofe proportions, that they are fimilar to the harmonic divifions of a monochord*. He does not indeed lay much ftrefs on this ; but it fhows that we like the appearance of principles ; and where we have not true ones, we have fome fatisfadion in producing fuch as are imaginary. N° II. TpHE defcription of the Hiding plates here promifed, and which hath been fince brought into ufe under va- rious names, with fome immaterial changes, is contained in a former letter to J. B. Efq. as follows : To J. B. Efq. at BoJloUf in Neiv-England. Dear Sir, London, Dec. 2, 1758. I HAVE executed here an eafy fimple contrivance, that I have long fince had in fpeculation, for keeping rooms warmer * " It may be juft remarked here, that upon comparing thcfe proportions with thofe arifing " from the common divifions of the monochord, it happens that the firft aiifwers to unifon, " and although the fecond is a difcord, the third ar.fwers to the third minor, the fourth tothe " third major, the fifth to the fourth, the fixth to the fift!), aaid the feveiith lo the oaave." Nutshells, page 85. APPENDIX. 29; warmer in cold weather than they generally are, and with lefs fire. It is this. The opening of the chimney is con- traaed, by brick-work faced with marble flabs, to about two feet between the jams, and the breaft brought down to within about three feet of the hearth. — An iron frame is placed jufl: under the breaft, and extending quite to the back of the chimney, fo that a plate of the fame metal may Aide horizontally backwards and forwards in the grooves on each fide of the frame. This plate is juft fo large as to fill the whole fpace, and fhut the chimney en- tirely when thruft quite in, which is convenient when there is no fire. Drawing it out, fo as to leave a fpace between its further edge and the back, of about two inches; this fpace is fufficient for the fmoke to pafs ; and fo large a part of the funnel being ftopt by the reft of the plate, the paftage of warm air out of the room, up the chimney, is obftrucft- ed and retarded, and by that means much cold air is pre- vented from coming in through crevices, to fupply its place. This effect is made manifeft three ways. Firft, when the fire burns brifkly in cold weather, the howling or whiftling noife made by the wind, as it enters the room through the crevices, when the chimney is open as ufual, ccafes as foon as the plate is Aid in to its proper diftance. Secondly, opening the door of the room about half an inch, and holding your hand againft the opening, near the top of the door, you feel the cold air coming in againft your hand, but weakly, if the plate be in. Let another perfon fuddenly draw it out, fo as to let the air of the room go up the chimney, with its ufual freedom where chimneys are open, and you immediately feel the cold air rufliing in ftrongly. Thirdly, if fomething be fet againft the door, juft fufficient, when the plate is in, to keep the door nearly Ihut, by refifting the prefliire of the air that would force it open: Then, when the plate is drav/n out, the door will be forced open by the increafed prefiTure of the outward cold air endeavouring to get in to fupply the place of the warxii. 30 APPENDIX. warm air, that now pafles out of the room to go up the chimney. In our common open chimneys, half the fuel is wafted, and its effect loft; the air it has warmed being immediately drawn off. Several of my acquaintance hav- ing feen this fimple machine in my room, have imitated it at their own houfes, and it feems likely to become pretty common. I defcribe it thus particularly to you, becaufe I think it would be ufeful in Bojlon-, where firing is often dear. Mentioning chimneys puts me in mind of a property I formerly had occafion to obferve in them, which I have not found taken notice of by others; it is, that in the fum- mer time, when no fire is made in the chimneys, there is, neverthelefs, a regular draft of air through them; continu- ally palTmg upwards, from about five or fix o'clock in the afternoon, till eight or nine o'clock the next morning, M^hen the current begins to flacken and hefitate a little, for about half an hour, and then fets as ftrongly down again, which it continues to do till towards five in the afternoon, then flackens and hefitates as before, going fometimes a little up, then a little down, till in about a half an hour it gets into a fteady upward current for the night, which con- tinues till eight or nine the next day; the hours varying a little as the days lengthen and fhorten, and fometimes va- rying from fudden changes in the weather; as if, after be- ing long warm, it Ihould begin to grow cool about noon, while the air was coming down the chimney, the current will then change earlier than the ufi.ial hour, <^c. This property in chimneys I imagine we might turn to fome account, and render improper, for the future, the old faying, as iifelefs as a chimney infiamner. If the opening of the chimney, from the breaft down to the hearth, be clofed by a llight moveable frame or two, in the manner of doors, covered with canvas, that will let the air through, but keep out the flies; and another little frame fet within upon the hearth, with hooks on which to hang joints of meat, fowls, d;v. wrapt well in wet linen cloths, three or four APPENDIX. 31 four fold, I am confident that if the linen is kept wet, by fprinkling it once a day, the meat would be fo cooled by the evaporation, carried on continually by means of the palhng air, that it would keep a week or more in the hotteft wea- ther. Butler and milk might likewife be kept cool, in vef- fels or bottles covered with wet cloths. A Ihallow tray, or keelcr, fhould be under the frame to receive any water that might drip from the wetted cloths. I think, too, that this property of chimneys might, by means of fmoke-jack vanes, be applied to fome mechanical purpofes, where a fmall but pretty conftant power only is wanted. If you would have my opinion of the caufe of this chang- ing current of air in chimneys, it is, in fliort, as follows. In lummer time there is generally a great difference in the warmth of the air at mid-day and midnight, and, of courfe, a difference of fpecific gravity in the air, as the more it is warmed the more it is rarefied. The funnel of a chimney being for the moft part fiarrounded by the houfe, is pro- teded, in a great meaiiire, from the diredt adtion of the fun's rays, and alfo from the coldnefs of the night air. It thence preferves a middle temperature between the heat of the day, and the coldnefs of the night. This middle tem- perature it communicates to the air contained in it. If the ftate of the outward air be cooler than that in the fun- nel of the chimney, it will, by being heavier, force it to rife, and go out at the top. What fiapplies its place from below, being warmed, in its turn, by the warmer funnel, is likewife forced up by the colder and weightier air below, and fo the current is continued till the next day, when the fun gradually changes the ftate of the outward air, makes it firft as warm as the funnel of the chimney can make it, (when the current begins to hefitate) and afterwards warm- er. Then the funnel being cooler than the air that comes into it, cools that air, makes it heavier than the outward air, of courfe it defcends; and what fucceeds it from a- bove, being cooled in its turn, the defcending current con- tinues: 32 APPENDIX. tinucs till towards evening, when it again liefitates and changes its courfe, from the change of warmth in the outward air, and the nearly remaining fame middle tem- perature in the funnel. Upon this principle, if a houfe were built behind Beacofi- hilly an adit carried from one of the doors into the hill ho- rizontally, till it met with a perpendicular ihaft funk from its top, it feems probable to me, that thofe who lived in the houfe, would conftantly, in the heat even of the calmeft day, have as much cool air paffmg through the houfe, as they fhould chufe; and the fame, though reverfed in its current, during the flilleft night. I think, too, this property might be made of ufe to mi- ners; as where feveral fhafts or pits are funk perpendicu- larly into the earth, communicating at bottom by horizon- tal paffages, which is a common cafe, if a chimney of thirty or forty feet high were built over one of the fhafts, or fo near the ihaft, that the chimney might communicate with the top of the fhaft, all air being excluded but what fhould pafs up or down by the fhaft, a conflant change of air would, by this means, be produced in the paflages below, tending to fecure the workmen from thofe damps which fo frequently incommode them. For the frefh air would be almoft always going down the open fhaft, to go up the chimney, or down the chimney to go up the fliaft. Let me add one obfervation more, which is, that if that part of the funnel of a chimney, which appears above the roof of a houfe, be pretty long, and have three of its fides expofed to the heat of the fun fucceffively, viz. when he is in the eaft, in the fouth, and in the weft, while the north fide is fheltered by the building from the cool northerly winds ; fuch a chimney will often be fo heated by the fun, as to continue the draft ftrongly upwards, through the whole twenty four hours, and often for many days toge- ther. If the outfide of fuch a chimney be painted black, the efFed: will be ftill greater, and the current ftronger. N° III. APPENDIX. S3 N" III. T T is faid the northern Chhiefe have a method of warm- ing their ground floors, which is ingenious. Thofe floors are made of tile a foot fquare and two inches thick, their corners being fupported by bricks fet on end, that are a foot long and four inches fquare, the tiles, too, join into each other, by ridges and hollows along their fides. This forms a hollow under the whole floor, which on one fide of the houfe has an opening into the air, where a fire is made, and it has a funnel riling from the other fide to carry off the fmoke. The fuel is a fulphurous pitcoal, the fmell of which in the room is thus avoided, while the floor and of courfe the room is well warmed. But as the underfide of the floor muft grow foul with foot, and a thick coat of foot prevents much of the dire£l application of the hot air to the tiles, I conceive that burning the fmoke by obliging it to defcend through red coals, would in this conrtrudlion be very advantageous, as more heat would be given by the flame than by the fmoke, and the floor be- ing thereby kept free from foot would be more heated with lefs fire. For this purpofe I would propofe ereding the funnel clofe to the grate, fo as to have only an iron plate between the fire and the funnel, through which plate the air in the funnel being heated, it will be fure to draw well, and force the fmoke to defcend, as in the figure Fieure'o "v^'here A is the funnel or chimney, B the grate on which the fire is placed, C one of the apertures through which the defcending fmoke is drawn into the chan- nel D of figure lo, along which channel it is conveyed by a circuitous rout, as defignated by the arrows, until it ar- rives at the ihiall aperture E, figure lo, through which it enters the funnel F. G in both figures is the iron plate againft which the fire is made, which being heated there- by, will rarefy the air in that part of the funnel, and caufe the finoke to afcend rapidly. The flame thus dividing E from 34 A P P E N D I S. from the grate to the right and left, and turning in paf— iages difpoied, as in figure 13, fo as that every part of the floor may be vifited by it before it enters the funnel F, by the two paflages E E, very little of the heat w^ill be loft,, and a winter room thus rendered very comfortable. N° IV. pAGE 8. Fe'w can tmagitte, &c. It is faid the Ice- landers have very little fuel, chiefly drift wood that comes upon their coaft. To receive more advantage from its heat, they make their doors low, and have a ftage round the room above the door, like a gallery, wherein the wo- men can fit and work, the men read or write, &c. The roof being tight, the warm air is confined by it and kept from rifing higher and efcaping ; and the cold air which enters the houfc when the door is opened, cannot rife above the level of the top of the door, becaufe it is hea- vier than the warm air above the door, and fo thofe in the gallery are not incommoded by it. Some of our too lofty rooms might have a ftage fo conftrufted as to make a tem- porary gallery above, for the winter, to be taken away in fummer. Sedentary people would find much comfort there in cold weather. N° V. p AGE 26. Where they ha've the art of managing it, &c. In fome houfes of the lower people among the northern nations of Europe, and among the poorer fort of Germans in Pennfylvania, I have obferved this conftru£tion, which appears very advantageous. A is the kitchen with its chim- ney ; B an iron ftove in the ftove-room. In a corner Fi^urJ'ii. °f ^^^ chimney is a hole through the back into the. ftove, to put in fuel, and another hole above it to let the fmoke of the ftove come back into the chimney. As foon as the cooking is over, the brands in the kitchen chimney are put APPENDIX. 35 put through the hole to fupply the (love, fo that there is feldom more than one fire burning at a time. In the floor over the ftove-room, is a Imall trap door, to let the warm air rife occafionally into the chamber. Thus the whole houfe is warmed at little expence of wood, and the flove- room kept conftantly warm ; fo that in the coldeft winter nights, they can work late, and find the room ftill com- fortable when they rife to work early. An Englifh farm- er in America who makes great fires in large open chim- neys, needs the conftant employment of one man to cut and haul wood for fupplying them ; and the draft of cold air to them is fo ftrong, that the heels of his family are frozen while they are fcorching their faces, and the room is never warm, fo that little fedentary work can be done by them in winter. The difference in this article alone of oeconomy, fhall, in a courfe of years, enable the Ger- man to buy out the Englifhman, and take pofTefTion of his plantation. - MISCELLANEOUS OBSERVATIONS. r^HIMNEYS whofe funnels go up in the north wall of a houfe and are expofed to the north winds, are not fo apt to draw well as thofe in a fouth wall ; becaufe whea rendered cold by thofe winds, they draw downwards. Chimneys enclofed in the body of a houfe are better than thofe whofe funnels are expofed in cold walls. Chimneys in ftacks are apt to draw better than feparate funnels, becaufe the funnels that have conftant fires in them, warm the others in fome degree that have none. One of the funnels in a houfe I once occupied, had a parti- cular funnel joined to the fouth fide of the ftack, fo that three ot its fides were expofed to the fun in the courfe of the day, viz. the eaft fide E during the morning, the fouth fide ri'uriij. ^ i" ^^^ middle part of the day, and the weft fide W during the afternoon, while its north fide was flielter- E 2 ed 36 APPENDIX. ed by the ftack from the cold whids. This funnel, which came from the ground floor, and had a confiderable height I above the roof, was conftantly in a ftrong drawing ftate day and night, winter and fummer. Blacking of funnels expofed to the fun, would probably make them draw ftill flronger. In Paris I faw a fire-place fo ingenioufly contrived as to ferve conveniently two rooms, a bedchamber and a ftudy. The funnel over the fire was round. The fire-place was I of caft iron, having an upright back A, and two ho- piate I. i-i-2;ontal femicircular plates B C, the whole fo order- Iigure 13. r _ '_ ed as to turn on the pivots D E. The plate B al- ways flopped that part of the round funnel that was next to the room without fire, while the other half of the fun- nel over the fire was always open. By this means a fervant ^ in the morning could make a fire on the hearth C, then in |- the ftudy, without difturbing the mafter by going into his f chamber ; and the mailer when he rofe, could with a touch of his foot turn the chimney on its pivots, and bring the { fire into his chamber, keep it there as long as he wanted. it, and turn it again when he went out into his ftudy. The room which had no fire in it, was alfo warmed by the heat coming through the back plate, and fpreading iu the room as it could not go up the chimney. Explanation auutuuiM-um^Mgatitt^ p/<>/f I 'llllllllllllllllllll'liil V^S' iiSi-r.-m-n'rt.i B /M./6~. /)j-. 3 ■ tm ./^ • ^ J^ F.g.s. "i Mm iiiiL. ' . ■ . I J,' 1,! !.,;'.. | jt ^i«i iai 'lE'iMMiiimiiinu aiiniiiiiiim: ■'llNllllHHIIIIIIIIIIMHIIMIUIIIIIlNUIIIllilllllllMIIIUWIlllllllH^ /Y.,i, 1 /" ' L^i« H /If. 16. A h ^^■7- \ n^ /la .iU. A" ••A^\ W:''.' »',.Z-'^ti^..r./y.:..^'. ■ [27 ] N° 11. I Explanation of an Optical Deception.. BY D. RITTENHOUSE. ^^t^"o^ OOME experiments were long ago commu- k3 nicated to the Royal Society of London, fhewing, that through the double microfcope, the furfaces of bodies fometimes appear to be reverfed, that is, thofe parts which are elevated feem depreffed, and the contrary. But the caufe of this appearance, for any thing I know, remains ftill to be explained. In order to produce this effe<£l, no other apparatus is neceffary than two convex lenfes placed in a tube, at a diftance from each other nearly equal to the fum of their focal diflances. Through thefe glalfes, objects that appear diftindly, always appear inverted ; for they are not feeii diredtly, but by means of an image formed either between the two glafles, or between both of them and the eye. If we look through fuch glafles at cornifhes, pifture frames and other mouldings in carpenters work, and fome forts of carved work, thofe parts which are raifed general- ly appear deprefl^ed, and thofe parts which are deprefled appear raifed. But a very ready objed, and which fuc- ceeds as well as any thing I know of, is a brick pave- ment ; whether it be a chimney-hearth, or pavement out of doors. Viewed through the tube above defcribed, every little cavity in the bricks, and the chinks between them, almoft always appear to be fo many elevations above the lurface of the bricks. When I confiderfed this odd appearance, the firfl pro- bable caufe that off'crcd was, that thofe parts of the object which are funk, and fartheft from the eye, might have their correfpondent parts of the image formed by the glaf— fes neareft to the eye, and therefore would appear raifed. But 38 EXPLANATION of an But this is not the cafe; for thofe parts which are fartheft from the eye in the obje£t, will always be fartheft from, the eye in the image, and often in a much greater propor- tion. After fome time I concluded it to be a neceffary confequencc of the apparent inverfion of the obje£t ; and many things tended to confirm me in this opinion, before I made the experiments which feem perfectly decifive. It has often been matter of fur prize to me, when view- ing the moon through a good telefcope, in company with perfons not accuftomed to fuch obfervations, that whilft the cavities and eminences of the moon's furface appeared to me marked out with the utmoft certainty by their light and fhades, my companions generally conceived it to be a plain furface of various degrees of brightnefs. The rea- fon I fuppofe to be this ; the aftronomer knows from the moon's fituation with refpeft to the fun, and even from the figure of its enlightened part, precifely in what direc- tion the light falls on its furface, and therefore judges rightly of its hills and vallies, from their different degrees of light, according to thofe rules which are imperceptibly formed in the mind, and confirmed by long experience. But a perfon unacquainted with aftronomy knows nothing of the direction of the fun's light on the moon, nor does he attend to the moon's globular figure, and is befides, perhaps, poffefled with a notion of its being felf-luminous; no- wonder then that the fame objedl; has a very different efFe£t on his imagination. It feems to be thofe rules of judging, which we begin to form in our earlieft infancy, which we fet alide, re-elhiblifh, alter, corred: and confirm, and at length rely on with the utmoft confidence, even without knowing that we do fo, or that we have any fuch rules : It is thefe rules, of fiich infinite general ufe to us, that fometimes miflead us on new and extraordinary oc- cafions, and particularly in the cafe now before us. A perfon entering into a room perceives, at a fingle glance, whence the light comes which illuminates the objedls be- fore OPTICAL DECEPTION. 39 fore him ; and tliat without remaining confcious for a mo- ment that he has attended to this circumftance : But the effed; remains, and will influence his judgment. If on looking at a brick hearth he perceives that thofe lines which divide the bricks have a dark fhade on that fide oppoiite to the light, and a bright ftreak on the contrary fide next to the light, he muft at the fame time perceive that they have the property which he has conftantly obferved in ridges, not in furrows. And iince the appearance ot the hearth will be fijch, through the glaiTes, in confequence of their inverting the fituation of its feveral parts, with refpect to the light, the obferver will inftantly pronounce the chinks between the bricks, and every little cavity in them, to be fo many perfect elevations above the common furface, nor can any effort of the mind corredt the imagination or alter the appearance. Though I was well fatisfied of the truth of this expla- nation, 1 relolved nevertheleis to bring it to the teft of ex- periment, which I did in the following manner. In order to give my experiment fair play, 1 fhut all the windows of my chamber excepting one dire£tly oppofite to the chimney. I then took the tube, with two convex glafles, and looking through it at the hearth, all the bricks appeared deprefled and the clefts between them elevated, as ufijal. I then placed a looking-glafs againft the chim- ney back, fo that it refle(fled the light from the window upon the hearth, and fet up a fmall board before the hearth to intercept the dire£l light ot the window from it. Then looking at the hearth through the glalfes, I was much pleafed to find it appear in its natural ftate, with the bricks elevated. I then fat down on a chair at the edge of the hearth, and looking through the tube which I held to my eye with one hand, whilft with the other I moved the board fo as to make it fometimes intercept the direcl light: of the window, and at other times the reflected light of the looking-glafs, 1 conftantly found that when the hearth; waa- 4© EXPLANATION of an was Illuminated by refleded light, it appeared in its na- tural ftate, and when illuminated by the diretl light, in its unnatural ftate ; for fo I call it when the bricks appear de- prefled and the chinks between them elevated. I then confidered that fince the hearth appeared in its natural ftate by refleded light, and in its unnatural ftate by dired light, only in confequence of the inverting pro- perty of the glaftes, the appearance ought to be diredly the contrary when it was viewed with the naked eye. And accordingly I found, upon taking out both of the glafles, and looking through the open tube, that the hearth ap- peared as perfedly, and as conftantly in its unnatural ftate by refleded light, and in its natural ftate by dired light, as it had before done the reverfe through the glafles. But it muft be obferved that fomething like a tube is neceflary to confine the fight from other adjoining objeds, which not being in the fame circumftances would otherwife corred the imagination. If we look through fuch a tube and glaflfes at the hearth or other objed, fuppofe a piece ot chocolate, the furrows in it appear fo many ridges, on removing the tube they fink into furrows, on applying it they again rife into ridges, and the illufion mij^ht perhaps be repeated a thoufand times, without the mind being at all able to conceive the objed to appear through the tube like what it really is. But if whilft you are looking through the tube, and the objed appears in its unnatural ftate, that is, when its fur- rows appear ridges, you apply your finger and feel that they really are furrows, the deception vaniflies in a mo- ment and the objed appears in its natural ftate. This I at firft fuppofed to arife from the fuperior confidence which we have in the fenfe ot touching, as knowing by experi- ence that this fenfe more perfedly reprefents the figure of bodies than the fight does. But I was, at leaft in part, miftaken. For if whilft you fee the objed in its unnatu- ral ftate, another perfon puts his finger to the part you are looking OPTICAL DECEPTION. 41 looking at, the deception vaniflies as well as in the former cafe. The application of a writing pen or pencil will pro- duce the fame effed:. And, which is very remarkable, after the mind has been undeceived by thefe means once or twice, it does not readily admit of the impofition again: Though, as I obferved before, if it be done by removing the glafles, the deception will return again as often as you pleafe. ^ The truth feems to be, that the mind chufes the leaft difficulty; and though in confequence of the judg- ment it has formed concerning the diretlion of the light. It will fubmit to fuch a fmall impofition as to fuppofe one piece of chocolate may have ridges where others ufually have furrows, when indeed it has not, yet it will not rea- dily endure fuch a grofs one, as to fuppofe it to have cavities of the figure and colour of a finger or a writing pen. Or perhaps the vifible motion attending fuch application pro- duces the principal effed: in convincing the mind that thofe bodies are really elevated*, and then their fhades and mo- difications of the light, fhew in what diredion it falls on them; and the miffake of the mind in that particular be- ing redified, the whole obje£t muft affume its natural ap- pearance. The explanation 1 have given of this phrEnomenon will account for an odd circumflance mentioned (I think) by Mr. Short; which once appeared fo whimfical to me as nei- ther to merit credit or attention. Mr. Short carefully ex- amined the Cafl^egrain telefcope, and in all probability fet it by the fide of one of the Gregorian form, in order to de- termine its comparative merits : He gives the preference to the Gregorian, and mentions as a principal defed of the CaiTegrain telefcope, that it reprefents the mountains in the moon as vallies, and the contrary. I doubt not but this, F otherwife " Whilft I was making thefe experiments, I thought of a carved filver flioe buckle, as a very proper objefl to prevent a deception of this fort i'roin taking place. But placing it on a brick pavement, and looking at it through the glaffes, it neverthelefs appeared perfedly depreffed. Prccifely as if you had taken a huclde and brewing on it a white lliining powder, had preffcd ■it into the brick wliilft foft, and then removing the buckle, the glittering powder had remaiiiod ia the impreilion. 42 DESCRIPTION OF the otherwife unaccountable appearance, was occafioned intire- ]y by its inverting the obje£l, for the reafons above given. If it be afked, why then do not the common long refrac- tors, which generally invert, produce the fame decepti- on? I anfwer, very probably they would do fo if fet befide a Gregorian refledlor and the eye applied alternately to the one and to the other*,. N° III. Defcnption of the White Mountains in Neii'-HampJIAre^ By the Rev. JEREMY BELKNAP of New-Hampshire. Readoa. T I ijJE white mountains in the northern part X of New-Hampfhire have, from the earlieft fettlement of the country, attra and about tnuel've miles from U niou-To'wn, in Fayette county., in the fate of Penn— fylvama.. BY THO. HUTCH INS. f ''4 ^Tu T^ HIS cafcade is occafioncd by a rock of a fe- 3l micircular forna, the chord of which, from one extreme end of the arch to the other, is nearly one hundred yards ; the arch or circular part is extenfive, and upwards of twenty feet in height, exhibiting a grand and romantic appearance. This very curious produdtion is compofed of ftonc of variegated colours, and a fpecies of marble beautifully chequered with veins running in dif- ferent directions, prefcnting on a clofe infpedion a faint refemblance of a variety of mathematical figures of diffe- rent angles and magnitudes. The operations of nature in this ftrudlure feems to be exceedingly '.miform and ma- ieflic ; the layers or rows of ftone of which it is compofed are of various lengths and thicknefles, more refembling the effefts of art than nature. A flat thin ftone from eight to ten inches thick, about twenty feet wide, forms the upper part of this amphitheatre, over v/hich the ftream precipi- tates. The whole front of this rock is made up from top to bottom, as well as from one extremity of the arch to the other, of a regular fucceffion, principally, of limeftone, ftrata over ftrata, and each ftratum or row, projedling ia an horizontal dlredion a little further out than its bafe, un- til it terminates into one entire flat, thin, extenfive piece, as already mentioned; and which jets out at right angles or On HYGROMETERS. 51 or in a parallel line with the bottom, over which it im- pends fifteen or twenty feet, and that without columns or even a fingle pillar for its fupport. This circumftance, together with the grand circular walk between the front of the rock and the fheet of water falling from the fum- mit, exhibits fo noble and fingular an appearance, that a fpedator cannot behold it without admiration and delight. N° V. Letter to Mr. Nairne, of London. Pajfy, 7iear Paris, Noi/. 13th, 17S0. SIR, f/fs/iTst THE qualities hitherto fought in a hygrome- A ter, or inftrument to difcover the degrees of moifture and drynefs in the air, feem to have been, an aptitude to receive humidity readily from a moift air, and to part with it as readily to a dry air. Different fubltances have been found to poflefs more or lefs of this quality; but when we fhall have found the fubftance that has it in the greateft perfedion, there will ftill remain fome uncer- tainty in the conclufions to be drawn from the degree fhown by the inftrument, arifing from the adual ftate of the inftrument itfelf as to heat and cold. Thus, if two bottles or vefl^els of glafs or metal being filled, the one with cold and the other with hot water, are brought into a room, the moifture of the air in the room will attach itfelf in quantities to the furface erf the cold veffel, while if you ailually wet the furface of the hot veflel, the moifture will immediately quit it, and be abforbed by the fame air. And thus in a fudden change of the air from cold to warm, the inftrument remaining longer cold may condenfe and abforb more moifture, and mark the air as having become G 2 more 53 On hygrometers^ more humid than it is in reality, and the contrary in a. change trom warm to cold. But it fuch a fuddenly changing inftrument could be freed from thefe imperfedions, yet when the defign is to difcover the different degrees of humidity in the air of dif- ferent countries, I apprehend the quick fenfibility of the inftrument to be rather a difadvantage ; fmce, to draw the defired conclufions from it, a conftant and frequent obfer- vation day and night in each country will be neceffary for a year or years, and the mean of each different fet of ob- fervatlons is to be found and determined. After all which fome uncertainty will remain refpeding the different de- grees of exadlitude with whicfi different perfons may have made and taken notes of their obfervations. For thefe reafons, I apprehend that a fubftance which, though capable of being diftended by moifture and con- traded by drynefs, is fo flow in receiving and parting with its humidity that the frequent changes in the atmolphere have not time to affed it fenfibly, and which therefore fhould gradually take nearly the medium of all thofe changes and preferve it conftantly, would be the moft pro- per fubftance of which to make fuch an 'hygrometer. Such an inftrument, you, my dear fir, though without intending it, have made for me ; and I, without defiring or expeding it, have received from you. It is therefore with propriety that I addrefs to you the following account of it ; and the more, as you have both a head to contrive and a hand to execute the means of perfeding it. And I do this with greater pleafure, as it affords me the oppor- tunity of renewing that antient correfpondence and ac- quaintance with you, which to me was always fo pleafing and io inftrudive. You may poffibly remember, that in or about the year 1758, you made for me a fet of artificial magnets, fix in number, each five and a half inches long, half an inch broad, and cue eiohth of an inch thick. Thefe, with two pieces On hygrometers. 53 pieces of foft iron, which together equalled one of the magnets, were inclofed in a little box of mahogany wood, the grain of which ran with, and not acrofs, the length of the box ; and the box was doled by a little fliutter of the fame wood, the grain of which ran acrofs the box ; and the ends of this fliutting piece were bevelled fo as to fit and Aide in a kind of dovetail groove when the box was to be fliut or opened. I had been of opinion that good mahogany wood was not affeifled by moifture (o as to change its dimeniions, and that it was always to be found as the tools of the workman left it. Indeed the difference at different times in the fame country, is fo fmall as to be fcarcely in a com- mon way obfervable. Hence the box which was made fo as to allow fuflicient room for the magnets to Aide out and in freely, and, when in, aiforded them fo much play that by fliaking the box one could make them ffrike the op- pofite fides alternately, continued in the fame ftate all the time I remained in England, which was four years, with- out any apparent alteration. I left England in Auguft 1 762, and arrived at Philadelphia in OtSober the fame year. In a few weeks afier my arrival, being defirousof fhowing your magnets to a philofophical friend, I found them fo tight in the box, that it was with difHculty I got them out ; and conftantly during the two years I remain- ed there, viz. till November 1764, this difficulty of get- ting them out and in continued. The little fhutter too, as wood does not fhrink length ways of the grain, was found too long to enter its grooves, and not being ufed, was millaid and loft ; and I afterwards had another made that fitted. In December 1 764 I returned to England, and after fome time I obferved that my box was become full big enough for my magnets, and too wide for my new fliutter; which was fo much too fliort for its grooves, that it was apt to fall 54 On hygrometers. fall out; and to make it keep in, I lengthened it by adding to each end a little coat of fealing-wax. I continued in England more than ten years, and during all that time after the firR change, I perceived no alteration. The magnets had the fame freedom in their box, and the little fliutter continued with the added fealing-wax to fit its grooves, till fome weeks after my fecond return to A- merica. As I could not imagine any other caufe for this change of dimenfions in the box, when in the different countries, I concluded, firft generally that the air of England was moifter than that of America. And this 1 fuppofed an ef- fe£l of its being an ifland, where every wind that blew muft neceffarily pafs over fome fea before it arrived, and of courfe lick up fome vapour. I afterwards indeed doubt- ed whether it might be juft only fo far as related to the city of London, where I refided ; becaufe there are many caufes of moifture in the city air, which do not exift to the fame degree in the country ; fuch as the brewers and dyers boiling caldrons, and the great number of pots and teaket- tles continually on the fire, fending fourth abundance of vapour; and alfo the number of animals who by their breath continually increafe it; to which may be added, that even the vaft quantity of fea coals burnt there, do in kindling difcharge a great deal of moifture. When I was in England, the laft time, you alfo made for me a little achromatic pocket telefcope, the body was brafs, and it had a round cafe, (1 think of thin wood) covered with fliaa,rin. All the while I remained in England, though poflibly there might be fome fmall changes in the dimenfions of this cafe, I neither perceived nor fufpeded any. There was always comfortable room for the tele- fcope to flip in and out. But foon after I arrived in Ame- rica, which was in May i 775, the cafe became too fmall for the inftrument, it was with much difficulty and vari- ous contrivances that I got it out, and I could never after get On HYGROMETERS. 55 get it in again, during my ftay there, which was eighteen months. I brought it with me to Europe, but left the cafe as ufelefs, imagining that I fhould find the continental air of France as dry as that of Pennfylvania, where my mag- net box hadalfo returned a fecond time to its narrownefs, and pinched the pieces, as heretofore, obliging me too, to- fcrape the fealing-wax off the ends of the fhutter. I had not been long in France, before I was furprlfed to find, that my box was become as large as it had always been in England, the magnets entered and came out with the fame freedom, and, when in, I could rattle them againft its fides ; this has continued to be the cafe without fenfible variati- on. My habitation is out of Paris diftant almofl a league, fo that the moift air of the city cannot befuppofed to have much eiTe(it upon the box. 1 am on a high dry hill in a free air as likely to be dry as any air in France. Whence it feems probable that the air of England in general may as well as that of London, be moifter than the air of Ame- rica, fince that ot France is fo, and in a part fo diftant from, the fca. The greater drynefs of the air in America appears from fome other obfervations. The cabinet work formerly feat us from London, which confifted in thin plates of fine wood glued upon fir, never would ftand with us, the van- eering, as thofe plates are called, would get loofe and come off; both woods fhrinking, and their grains often croffmg, they were forever cracking and flying. And in my elec- trical experiments there, it was remarkable, that a maho- gany table on which my jars ftood under the prime con- duftor to be charged, would often be fo dry, particularly when the wind had been fome time at north-weft which with us is a very drying wind, as to ifolate the jars, and prevent their being charged till I had formed a communi- cation between their coatings and the earth. I had a like table in London which I ufed for the fame purpofe all the time I refided there; but it was never fo dry as to refufe- conducing the eledricity.. Now ^6 On hygrometers. Now what I would beg leave to recommend to you, is, that you would recoiled;, if you can, the fpecies of mahoga- ny of which you made my box, for you know there is a good deal of difference in woods that go under that name ; or if that cannot be, that you would take a number of pieces of the clofeft and fineft grained mahogany that you can meet with, plane them to the thinnefs of about a line, and the width of about two inches acrofs the grain, and fix each of the pieces in fome inftrument that you can con- trive, which will permit them to contract and dilate, and will fhow, in fenfible degrees, by a moveable hand upon a marked fcale, the otherwife lefs fenfible quantities of fuch contra£lion and dilatation. If thefe inftruments are all kept in the fame place while making, and are graduated together while fubje(5l to the fame degrees of moiflure or drynefs, I apprehend you will have fo many comparable hygrometers, which being fent into different countries, and continued there for fome time, will find and Ihovw there the mean of the different drynefs and moifture of the air of thofe countries, and that with much lefs trouble than by any hygrometer hitherto in ufe. With great efleem, I am, dear fir, Your mofi: obedient, And moft humble fervant, B. FRANKLIN. Defcriptlon [ 57 ] N° VI. Defcriptmi of a neiv Stove for burning of PitcoaU and confuming all its Smoke. BY DR. B. FRANKLIN. Read Janua- ry 18, I "' 786: npO WARDS the end of the laft century an X ingenious French philofopher, whofe name I am forry I cannot recoiled:, exhibited an experiment to Ihow that very offenfive things might be burnt in the middle of a chamber, fuch as woollen rags, feathers, &c. without creating the leafl: fmoke or fmell. The machine in which the experiment was made, if I pj,^„j."' remember right, was of this form, made of plate iron. Some clear burning charcoals were put into the opening of the fhort tube A, and fupported there by the grate B. The air as foon as the tubes grew warm would afcend in the longer leg C and go out at D, confequently air mufl: enter at A defcending to B. In this courfe it mufl be heated by the burning coals through which it pafl'ed, and rife more forcibly in the longer tube in proportion to its degree of heat or rarefaction, and length of that tube. For fuch a machine is a kind of inverted fyphon ; and as the greater weight of water in the longer leg of a common fyphon in defcending is accompanied by an afcent of the fame fluid in the fhorter ; fo, in this inverted fyphon, the greater quantity of levity of air in the longer leg, in rifing is accompanied by the defcent of air in the fhorter. The things to be burned being laid on the hot coals at A, the fmoke muft defcend through thofe coals, be converted into flame, which, after deftroying the ofi^enfive fmell, came out at the end of the longer tube as mere heated air. H Whoever 58 DESCRIPTION of a Whoever would repeat this experiment with fuccefs, mufl: take care that the partA , B, of the Ihort tube be quite full of burning coals, fo that no part of the fmoke may defcend and pafs by them without going through them, and being converted into flame ; and that the longer tube be fo heated as that the current of afcending hot air ia eftablifhed in it before the things to be burnt are laid on the coals ; otherwife there will be a difappointment. It does not appear either in the Memoirs of the Academy of Sciences, or Philofophical Tranfa£lions of the Englifli Royal Society, that any improvement was ever made of this ingenious experiment, by applying it to ufeful pur- pofes. But there is a German book, entitled Vulcaniis Famulans^ by Joh. George Leutmann, P. D. printed atWir- temberg in 1723, which defcribes, among a great variety of other floves for warming rooms, one which feems to have been formed on the fame principle, and probably from the hint thereby given, though the French experi- ment is not mentioned. This book being fcarce, I have tranflated the chapter defcribing the ftove, viz. " Vulcanus Famulans, by John George Leutmann, P. D. . " Wirtemberg, 1723. "CHAP. VII. " On a ftove, which draws downwards. " Here follows the defcription of a fort of ftove, which " can eafily be removed and again replaced at pleafure. " This drives the fire down under itfelf, and gives no " fmoke, but however a very unwholefome vapour. " In the figure, A is an iron veflel like a fun-- .Plate II. « j^gi jj-^ diameter at the top about twelve inches. Figure 20. ' X _ ' " at the bottom near the grate about five inches;. " its height twelve inches. This is fet on the barrel C, " which is ten inches diameter and two feet long, clofed " at N E W S T O V E. 59 "*' at each end E E. From one end rifes a pipe or flue " about tour inches diameter, on which other pieces of pipe *' are fet, which are gradually contradted to D, where the " opening is but about two inches. Thofe pipes mufl: to- " gether be at leaft four feet high. B is an iron grate. " F F are iron handles guarded with wood, by which the " ftove is to be lifted and moved. It ftands on three legs. *' Care mufl: be taken to flop well all the joints, that no " fmokc may leak through. " When this ftove is to be ufed, it muft firft be carried *' into the kitchen and placed in the chimney near the fire. " There burning wood muft be laid and left upon its grate " till the barrel C is warm, and the fmoke no longer rifes *' at A, but defcends towards C. Then it is to be carried *' into the room which it is to warm. When once the *' barrel C is warm, frefti wood may be thrown into the " veffel A as often as one pleafes, the flame defcends and *' without fmoke, which is fo confumed that only a va- *' pour palTes out at D. " As this vapour is unwholefome, and afl'ects the head, *' one may be freed from it, by fixing in the wall of the *' room an inverted funnel, fuch as people ufe to hang over *' lamps, through which their fmoke goes out as throut^h *' a chimney. This funnel carries out all the vapour cle- *♦ verly, fo that one finds no inconvenience from it, even *' though the opening D be placed a fpan below the mouth " of the faid funnel G. The neck of the funnel is better ♦' when made gradually bending, than if turned in a right " angle. " The caufe of the draft downwards in the ftove is the " preflure of the outward air, which falling into the veffel " A in a column of twelve inches diameter, finds only " a refifting paflage at the grate B, of five inches, and " one at D, of two inches, \\ hich are much too weak " to drive it back again ; befides, A ftands much higher *' than B, and fo the preflTure on it is greater and more H 2 " forcible. 6o DESCRIPTION of a « forcible, and beats down the flame to that part where " it finds the leaft refiftance. Carrying the machine firfl: " to the kitchen fire for preparation, is on this account, " that in the beginning the fire and fmoke naturally afcend, " till the air in the dole barrel C is made thinner by the " warmth. When that veflel is heated, the air in it is " rarefied, and then all the fmoke and fire defcends " under it. " The wood fhould be throughly dry, and cut into " pieces five or fix inches long, to fit it for being thrown " into the funnel A." Thus far the German book. It appears to me by Mr. Leutmann's explanation of the operation of this machine, that he did not underftand the principles of it, whence I conclude he was not the in- ventor of it; and by the defcription of it, wherein the opening at A is made fo large, and the pipe E, D, fo fhort, I am perfuaded he never made nor faw the experiment, for the firft ought to be much fmaller and the laft much higher, or it hardly will fucceed. The carrying it in the kitchen, too, every time the fire fhould happen to be out, muft be fo troublefome, that it is not likely ever to have been in prac- tice, and probably has never been fliown but as a philofo- phical experiment. The funnel for conveying the va- pour out of the room, would befides have been uncertain in its operation, as a wind blowing againft its mouth would drive the vapour back. The ftove I am about to defcribe, was alfo formed on the idea given by the French experiment, and completely carried into execution before I had any knowledge of the German invention; which I wonder fhould remain fo many years in a country where men are fo ingenious in the ma- nagement of fire, without receiving long fince the im- provements I have given it. Description N E W S T O V E. 6e Description of the Parts. A, the bottom plate which Hes flat upon the hearth, with its partitions 1,2, 3, 4, 5, 6, that plg^^J^j arc call: with it, and a groove Z Z, in which are to Aide, the bottom edges of the fmall plates Y, Y, figure 1 2 ; which plates meeting at X clofe the front. B I, figure 3, is the cover plate fhowing its under fide, with the grooves i, 2, 3, 4, 5, 6, to receive the top edges of the partitions that are fixed to the bottom plate. It fhows alfo the grate W W, the bars of which are caft in the plate, and a groove V V, which comes right over the groove Z Z, figure 2, receiving the upper edges of the fmall fliding plates Y Y, figure i 2. B 2, figure 4, {hows the upper fide of the fame plate, with a fquare impreffion or groove for receiving the bot- tom mouldings T T T T of the three fided box C, figure 5, which is caft in one piece. D, figure 6, its cover, fliowingits under fide with grooves to receive the upper edges S S S of the fides of C, figure 5, alfo a groove R, R, which when the cover is put on Gomes right over another Qj^in C, figure 5, between which it is to Aide. E, figure 7, the front plate of the box. P, a hole three inches diameter through the cover D, fi- gure 6, over which hole ftands the vafe F, figure 8, which has a correfponding hole two inches diameter through its bottom. The top of the vafe opens at O, O, O, figure 8, and turns, back upon a hinge behind when coals are, to be put in; the vafe has a grate within at N N of caft iron H, figure 9, and ahole in the top one and a half inches diameter to admit air, and to receive the ornamental brafs guilt flame M, figure 10, which ftands in that hole andj being itfelf hollow and open, fufFers air to pafs through it to the fire. G, figure II, is a drawer of plate iron, that flips in be- tween in the partitions 2 and 3, figure 2, to receive the falling 52 DESCRIPTION of a falling afhes. It is concealed when the fmall Aiding plates Y Y, figure 12, are (hut together. I, I, I, I, figure 8, is a niche built of brick in the chim- ney and plaftered. It clofes the chimney over the vafe, but leaves two funnels one in each corner communicating with the bottom box K K, figure 2. Dimensions of the Parts. Feet. In. . Front of the bottom box, ^ - - 20 Height of its partitions, - - ° 4t Length of N° i, 2, 3 and 4, each, - 13 Length of N° 5 and 6, each - - 08^ Breadth of the paflage between N ° 2 and 3,0 6 Breadth of the other paflages each, - o 34- Breadth of the grate, - - o 6i Length of ditto, - - - 08 Bottom moulding of box C, fquare, - 10 Height of the fides of ditto, - - 04 Length of the back fide, - - 010 Length of the right and left fides, each, - o 9 i Length of the front plate E, where longeft, o 1 1 The cover D, fquare, - - 012 Hole in ditto, diameter, - -03 Sliding plates Y Y their length, each, -10 —their breadth, each, - 04^ Drawer G, its length, - - - 10 •^breadth, - - - o 5t depth, _ _ - 04 — — depth of its further end, only, o i Grate H in the vafe, its diameter to the extre- mity of its knobs, - - - o 5I. Thicknefs of the bars at top, - - o 04. at bottom, lefs, - 00 Depth of the bars at the top, - - o oj Height of the vafe, - - -16 Diameter of the opening O, O, in the clear, o 8 Diameter NEW STOVE. 631 Fcot. In. Diameter of the air-hole at top, - - o i i.. of the flame hole at bottom, -02 To fix this Machine. Spread mortar on the hearth to bed the bottom plate A,, then lay that plate, level, equally diftant from each jamb, and projecting out as far as you think proper. Then put- ing Ibrae Windfor loam in the grooves of the cover B, lay that on: Trying the Aiding plates Y Y, to fee if they move freely in the groves Z Z, V V, defigned for them. Then begin to build the niche, obferving to leave the. fquare corners of the chimney unfilled; for they are to be funnels. And obferve alfo to leave a free open communi- cation between the palTages at K K, and the bottom of thofe funnels, and mind to clofe the chimney above the top of the niche, that no air may pafs up that way. The concave back of the niche will reft on the circular iron par- tition I A 4, figure 2, then with a little loam put on the, box C over the grate, the open fide of the box in front. Then, with loam in three of its grooves, the groove R R being left clean, and brought directly over the groove QJ^ in the box, put on the cover D, trying the front plate E, to fee if it Aides freely in thofe grooves. Laftly, fet on the vafe, which has fmall holes in the moulding of its bottom to receive two iron pins that rife out of the plate D at I I, for the better keeping it fteady. Then putting in the grate H, which refts on its three knobs H H H againft the infide of the vafe, and fiipping the drawer into its place ; the machine is fit for ufe. To tife it. Let the firft fire be made after eight in the evening or before eight in the morning, for at thofe times and be- tween thofe hours all night, there is ufually a draft up a chimney, though it has long been without fire ; but be- tween thofe hours in the day there is often in a cold chim- ney. 64 DESCRIPTION of a ney a draft downwards, when if you attempt to kindle a lire, the fmoke will come into the room. But to be certain of your proper time, hold a flame over the air-hole at the top. If the flame is drawn ftrongly down for a continuance, without whiffling, you may be- gin to kindle a fire. Firft put in a few charcoals on the grate H. Lay fome fmall flicks on the charcoals. Lay fome pieces of paper on the flicks, Kindle the paper with a candle. Then fliut down the top, and the air will pafs down through the air-hole, blow the flame of the paper down through the flicks, kindle them, and their flame pafling lower, kindles the charcoal. When the charcoal is well kindled, lay on It the fea- coals, obferving not to choak the fire by putting on too much at firft. The flame defcending through the hole in the bottom of the vafe, and that in plate D into the box C paffes down farther through the grate W W in plate B i, then pafles horizontally towards the back of the chimney ; there di- viding, and turning to the right and left, one part of it pafles round the far end of the partition 2, then coming forward it turns round the near end of partition i, then moving backward it arrives at the opening into the bottom of one of the upright corner funnels behind the niche, through which it afcends into the chimney, thus heating that half of the box and that fide of the niche. The other part of the divided flame pafles round the far end of par- tition 3, round the near end of partition 4, and fo into and up the other corner funnel, thus heating the other half of the box, and the other fide of t-he niche. The vafe itfelf, and the box C will alfo be very hot, and the air furrounding them being heated, and rifing, as it cannot get into the chimney, it fpreads in the room, colder air fucceeding N E W S T O V E. 6s fucceeding is warmed in its turn, rifes and fpreads, till by the continual circulation the whole is warmed. If you fliould have occafion to make your firfl. fire at hours not fo convenient as thofe above mentioned, and when the chimney does not draw, do not begin it in the vafe, but in one or more of the paflages of the lower plate, firft covering the mouth of the vafe. After the chimney has drawn a while with the fire thus low, and begins to be a little warm, you may clofe thofe pafl~ages and l-indle another fire in the box C, leaving its Aiding ihutter a little open ; and when you find after fome time that the chim- ney being warmed draws forcibly, you may fhut that paf- fage, open your vafe, and kindle your fire there, as above direded. The chimney well warmed by the firft day's fire will continue to draw conftantly all winter, if fires a^e made daily. You will, in the management of your fire, have need of the following implements : A pair of fmall light tongs, twelve or fifteen inches long, plate II, figure 13. A light poker about the fame length with a flat broad point, figure 14. A rake to draw aflies out of the paflages of the low- er plate, where the lighter kind efcaping the afli-box will gather by degrees, and perhaps once in a week or ten days require being removed, figure 15. And a fork with its prongs wide enough to flip on the neck of the vafe cover, in order to raife and open it when hot, to put in frcfh coals, figure 16. In the management of this ftove there are certain pre- cautions to be obferved, at firft with attention, till they become habitual. To avoid the inconvenience of fmoke, fee that the grate H be clear before you begin to light a frefh fire. If you find it clogged with cinders and afties, turn it up with your tongs and let them fall upon the grate below } the alhes will go through it, and the cinders may I be ee DESCRIPTION OF A be raked off and returned into the vafe when you would burn them. Then fee that all the Aiding plates are in their places and clofe fhut, that no air may enter the ftove but through the round opening at the top of the vafe. And to avoid the inconvenience of dufl from the afhes, let the afh-drawer be taken out of the room to be emptied ; and when you rake the paffages, do it when the draft of the air is ilrong inwards, and put the afhes carefully into the alh-box, that remaining in its place. If being about to go abroad, you would prevent your fire burning in your abfence, you may do it by taking the brafs flame from the top of the vafe, and covering the paflage with a round tin plate, which will prevent the en- try of more air than barely fufficient to keep a few of the coals alive. When you return, though fome hours abfent, by taking off the tin plate and admitting the air, your fire will foon be recovered. The effed of this machine, well managed, is to bura not only the coals, but all the fmoke of the coals, fo that while the fire is burning, if you go out and obferve the top of your chimney, you will fee no fmoke iffuing, nor any thing but clear warm air, which as ufual makes the bodies feen through it appear waving. But let none imagine from this, that it may be a cure fiar bad or fmoky chimneys, much lefs, that as it burns the fmoke it may be ufed in a room that has no chimney. 'Tiy by the help of a good chimney, the higher the better, that it produces its effeft; and though a flue of plate iron fufficiently high might be raifed in a very lofly room., the management to prevent all difagreeable vapour would be too nice for common practice, and fmall errors would have unpleafmg confequences. It is certain that clean iron yields no ofFenfive fmell when heated. Whatever of that kind you perceive, where there are iron floves, proceeds therefore from fome foul- nefs burning or fuming on their furface. They fhould therefore • NEW STOVE, C; therefore never be fpit upon, or greafed, nor fhould any duft be fuffered to lie upon them. But as the greateft care will not always prevent thefe things, it is well once a week to wafh the ftove with foap lees and a brufh, rlnfing it with clean water. The Advantages of this Stove. 1. The chimney does not grow foul, nor ever need fvveeping; for as no fmoke enters it, no foot can form in it. 2. The air heated over common fires inftantly quits the room and goes up the chimney with the fmoke; but in the ftove, it is obliged to deicend in liame and pals through the long winding horizontal palTages, communi- cating its heat to a body of iron plate, which having thus time to receive the heat, communicates the fame to the air of the room, and thereby warms it to a greater degree. 3. The whole of the fuel is confume d by beingturned into flame, and you have the benefit of its heat, whereas in common chimneys a great part goes away in fmoke which you fee as It rifes, but it affords you no rays of warmth. One may obtain fome notion of the quantity of fuel thus wafted in fmoke, by refle£ling on the quantity of foot that a few weeks firing will lodge agalnlt the fides of the chimney, and yet this is formed only of thofe par- ticles of the column of fmoke that happen to touch the fides in its afcent. How much more muft have palled ofl" in the air ? And we know that this foot is ftill fuel ; for it will burn and flame as fuch, and when hard caked toge- ther Is indeed very like and almoft as folid as the coal it proceeds from. Thedefirudlion of your fuel goes on near- ly in the fame quantity whether in fmoke or in flame : but there is no comparifon in the difference of heat <.'iven. Obferve when frelh coals are firft put on your fire, what a body of fmoke arifes. This fmoke is for a long time too cold to take flame. If you then plunge a burning candle into it, the candle inftead of inflaming the fmoke will in- 1 2 flantly 68 DESCRIPTION OF A ftantly be itfelf extinguifhed. Smoke muft have a ccrtafre degree of heat to be inflammable. As foon as it has ac- quired that degree, the approach of a candle will inflame the whole body, and you will be very fenfible of the dif- ference of the heat it gives. A ftill eafier experiment may be made with the candle itfelf. Hold your hand near the- fide of its flame, and obferve the heat it gives ; then blow it out, the hand remaining in the fame place, and obferve what heat may be given by the fmoke that rifes from the flill burning fnufF. You will find it very little. And yet that fmoke has in it the fubftance of fo much flame, and will inftantly produce it, if you hold another candle above it fo as to kindle it. Now the fmoke from the frefh coals laid on this ftove, inflead of afcending and leaving the fire while too cold to burn, being obliged to defcend through the burning coals, receives among them that degree of heat which converts it into flame, and the heat of that flame is communicated to the air of the room, as above explained. 4. The flame from the frefh coals laid on in this ftove,, defcending through the coals already ignited, preferves. them long from confuming, and continues them in the ftate of red coals as long as the flame continues that fur- rounds them, by which means the fires made in this ftove. are of much longer duration than in any other, and fewer coals are therefore neceftary for a day. This is a very material advantage indeed. That flame fliould be a kind of pickle, to preferve burning coals from confuming, may feem a paradox to many, and very unlikely to be true, as it appeared to me the firft time I obferved the fad. I muft therefore relate the circumftances, and fliall mention an eafy experiment, by which my reader may be in poflefllon of every thing neceftary to the underllanding of it. In the firft trial 1 made of this kind of ftove, v, hich was con- flru£led of thin plate iron, I had inftead of the vafe a kind of inverted pyramid like a mill-hopper ; and fearing at firft N E W S T O V E. 6g •firft that the fmall grate contained in it mi^ht be clogged by cynders, and the palTage of the flame fometimes ob- truded, I ordered a little door near the grate, by means of which I might on occafion clear it. Though after the ftove was made, and before I tried it, I began to think this precaution fuperfluous, from an imagination, that the flame being contracted in the narrow part where the grate was placed, would be more powerful in confuming what it fhould there meet with, and that any cynders between or near the bars would be prefently deftroyed and the paf- fage opened. After the ftove was fixed and in adion, I had a pleafure now and then in opening that door a little, to fee through the crevice how the flame defcended among the red coals, and obferving once a fingle coal lodged on the bars in the middle of the focus, a fancy took me to obferve by my watch in how fhort a time it would be con- fumed. I looked at it long without perceiving it to be at all diminifhed, which furprifed me greatly. At length it occurred to me, that I and many others had feen the fame thing thoufands of times, in the confervation of the red coal formed in the fnuff of a burning candle, which while cnvelloped in flame, and thereby prevented from the con- tad of palling air, is long continued and augments inftead of diminilhing, fo that we are often obliged to remove it by the fnuffers, or bend it out of the flame into the air, where it confumes prefently to aflies. I then fuppofed that to confume a body by fire, paffing air was necelTary to receive and carry off the feparated panicles of the body; and that the air paffing in the flame of my ftove, and in the flame of a candle, being already faturated with fuch particles, could not receive more, and therefore left the coal undiminilhed as long as the outward air was prevent- ed from coming to it by the furrounding flame, which kept it in a fituation fomewhat like that of charcoal in a well luted crucible, which, though long kept in a ilrong. fire, comes out unconfumed. Am yo DESCRIPTION OF A An eafy experiment will fatisfy any one of this con- ferving power of flame envelloping red coal. Take a fmall Hick of deal or other wood the fize of a goofe quill, and hold it horizontally and fteadily in the flame of the can- dle above the wick, without touching it, but in the body of the flame. The wood will firft be inflamed, and burn beyond the edge of the flame of the candle, perhaps a quarter of an inch. When the flame of the wood goes out, it will leave a red coal at the end of the flick, part of which will be in the flame of the candle and part out in the air. In a minute or two you will perceive the coal in the air diminifh gradually, fo as to form a neck; while the part in the flame continues of its firft fize, and at length the neck being quite confumed it drops ofi^; and by rolling it between your fingers when extinguifhed you will find it ftill a folid coal. However, as one cannot be always putting on frefli fuel in this ftove to furnifh a continual flame as is done in a candle, the air in the intervals of time gets at the red coals and confumes them. Yet the confervation while it lafted, fo much delayed the confumption of the coals, that two fires, one made in the morning, and the other in the af- ternoon, each made by only a hattuU of coals, were fufiici- ent to keep my writing room, about fixteen feet fquare and ten high, warm a whole day. The fire kindled at feven in the morning would burn till noon ; and all the iron of the machine with the walls of the niche being thereby heated, the room kept warm till evening, w^hen another fmaller fire kindled kept it warm till midnight. Infteadof the Aiding plate E, which flints the front of the box C, I Ibmetimes ufed another which had a pane of glafs, or, which isbetter, of Mufcovy talc, that the flamemightbe feen delcending from the bottom of the vafe and pafling in a column through the box C, into the cavities of the bottom plate, like water falling from a funnel, admirable to fuch as are not acquainted with the nature of the machine, and in itfelf a pleafing fpedacle. Every N E \V S T O V E. 71 Every utenfil, however properly contrived to ferve its purpoi'e, requires fome practice before it can be ufed adroit- ly. Put into the hands of a man for the firft time, a gim- blct or a hammer, (very fimple inflruments) and tell him the ufe of them, he fhall neither bore a hole or drive a nail with the dexterity or fuccefs of another who has been a little accuftorned to handle them. The beginner therefore ia the ufe of this machine, will do well not to be difcouraged with little accidents that may arife at firft from his want of experience. Being fomewhat complex, it requires as already faid a variety of attentions; habit will render them unneceflary. And the ftudious man who is much in his chamber, and has a pleafure in managing his own fire, will foon find this a machine moft comfortable and delight- ful. To others who leave their fires to the care of ignorant fervants, 1 do not recommend it. They v.'ill with diffi- culty acquire the knowledge neceffary, and will make fre- quent blunders that will fill your room with fmoke. It is therefore by no means fit for common ufe in families. It may be advifeable to begin with the flaming kind of ftone coal, which is large, and, not cakinc^ together, is not fo apt to clo;^; the grate After fome experience, any kind of coal may be ufed, and with this advantage, that no fmell, even from the moft fulphurous kind can come into your room, the current of air being conftantly into the vafe, where too that fmell is all confumed. The vafe form was chofen as being elegant in itfelf, and very proper for burning of coals : Where wood is the ufual fuel, and muft be burnt in pieces of fome length, a long fquare cheft maybefubftituted, in which A is the co- ver opening by a hinge behind, B the grate, C the pigj^'i, hearth box with its divifions as in the other, D the plan of the cheft, E the long narrow grate. 'I his 1 have not tried, but the vafe machine was compleated in 1771, and ufed by me in London three winters, and one afterwards in America, much to my fatisf a(ftion ; and I have not yet tliought 72 DESCRIPTION of a thought of any improvement it may be capable of, though fuch may occur to others. For common ufe, while in France, I have contrived another grate for coals, which has in part the fame property of burning the fmolce and pre- ferving the red coals longer by the flame, though not fo completely, as in the vafe, yet fufficiently to be very ufeful, which I fhall now defcribe as follows. A, is a round grate, one foot (French) in dia- pj'^jf^'^jg iiieter, and eight inches deep between the bars and the back; the fides and back of plate iron; the fides hav- ing holesof half an inch diameter difl;ant3 or 4 inches from each other, to let in air for enlivening the fire. The back without holes. The fides do not meet at top nor at bot- tom by eight inches: that fquare is filled by grates of fmall bars croifing front to back to let in air below, and let out the fmoke or flame above. The three middle bars of the front grate are fixed, the upper and lower may be taken out and put in at pleafure, when hot, with a pair of pincers. This round grate turns upon an axis, fupported by the crotchet B, the ftem of which is an inverted conical tube five inches deep, which comes on as many inches upon a pin that fits it, and which is fixed upright in a call iron plate D, that lies upon the hearth; in the middle of the top and bottom grates are fixed fmall upright pieces E E about an inch high, which as the whole is turned on its axis flop it when the grate is perpendicular. Figure 19 is another view of the fame machine. In making the firfl: fire in a morning with this grate, there is nothing particular to be obferved. It is made as in other grates, the coals being put in above, after taking out the upper bar, and replacing it when they are in. The roiuid figure of the fire when thoroughly kindled is agree- able, it reprefents the great giver of warmth to our fyftem. As it burns down and leaves a vacancy above, which you ■would fill with frefh coals, the upper bar is to be taken out, and afterwards replaced. The frefli coals while the grate NEW STOVE. 73 ■grate continues in the fame pofition, will throw up as ufaal a body of thick fmoke. But every one accuftomed to coal ■fires in common grates, muft have obferved that pieces of frefli coal ftuck in below among the red coals have their •fmoke fo heated as that it becomes flame as faft as it is produced, which flame rifes among the coals and enlivens the appearance of the fire. Here then is the ufe of this fwivel grate. By a pufh with your tongs or poker, you turn it on its pin till it faces the back of the chimney, then turn it over on its axis gently till it again faces the room, whereby all the frefli coals will be found under the live coals, and the greater part of the fmoke arifing from the frefli coals will in its paflage through the live ones be heat- ed fo as to be converted into flame : Whence you have much more heat from them, and your red coals are lono^er preferved from confuming. I conceive this conftrudtion, though not fo complete a confumer of all the fmoke as the vafe, yet to be fitter for common ufe, and very advanta- geous. It gives too a full fight of the fire, always a plea- fing objedt, which we have not in the other. It may with a touch be turned more or lefs from any one of the com- pany that defires to have lefs of its heat, or prefented full to one juft come out of the cold. And fupported in a ho- rizontal pofition, a tea-kettle may be boiled on it. The author's defcription of his Pennfylvania fire-place, firft publiflied in 1744, having fallen into the hands of workmen in Europe, who did not, it feems, well compre- hend the principles of that machine, it was much dif- figured in their imitations of it; and one of its main in- tentions, that of admitting a fuflScient quantity of frefli air warmed in entering through the air-box, nearly de- feated, by a pretended improvement, in leflening its paf- fages to make more room for coals in a grate. On pre- tence of fuch improvements, they obtained patents for the invention, and for a while made great profit by the fale, till the public became fenfible of that dcfed, in the ex- K pedicd 74 T H E O R Y OF pe£led operation. If the fame thing fhould be attempted with this vafe flove, it will be well for the buyer to ex- amine thoroughly fuch pretended improvements, left, be- ing the mere productions of ignorance, they diminifh or defeat the advantages of the machine, and produce incon- venience and difappointment. The method of burning fmoke, by obliging it to defcend through hot coals, may be of great ufe in heating the walls of a hot-houfe. In the common way, the horizon- tal paiTiiges or flues that are made to go and return in thofe walls, lole a great deal of their efFe£l when they come to be foul with foot; for a thick blanket-like lining of foot prevents much of the hot air from touching and heating-: the brick work in its pafTage, fo that more fire muft be made as the flue grows fouler : But by burning the fmoke they are kept always clean. The fame method may alfo be of great advantage to thofe bufinelTes in which large coppers or caldrons are to be heated.. Written at Sea, 17S5. N° VIL. A Theory of Lightening and Thunder Storms, by Andrew Oliver, Efq. of Salem in the State of Mafachufetts. ^^''if;""' ¥ '^ ^^^ been generally, and, confidering the phe- J. nomena themfelves, very naturally fuppofed, that the eleftric charges which are exhibited in repeated flalhes of lightening during a thunder ftorm, are previoufly accumulated in the vapors which conftitute the cloud ; and that thefe vapors, when by any means they become either over-charged with elei£lric matter, or are deprived of their ^. ,,*.:..,.«.. natural THUNDER STORMS. 73 natural quantities of it*, difcharge their furplufage to, or receive the neceflary fuppHes from, either the earth or the neighbouring clouds, in fuccelTive explofions, till an equi- librium is reftored between them. But I ihall endeavour in the following pages to prove, that thefe charges refide, not in the cloud or vapors of which it confifls, but in the air which fuftains them ; and that, previous to the for- mation of the cloud, or even the aicent of the vapors of which it is formed. Eut, in order to convey my ideas upon this fubje£t with perfpicuity, I fmd it neceffiiry to introduce them with a quotation from dodor Franklin''^ letters on electricity, in which the doctor compares water, ■whether in its natural ftate, or rarefied into vapors, to a fponge ; and the electric fluid, in connedtion w^th it, to water appHed to the fponge. " When a fponge (fays he) is fomewhat condenfed by " being fqueezed between the fingers, it will not receive " and retain fo much water as when it is in its more loofe " and open ftate. If more fqueezed and condenfed, fome " of the water will come out of its inner parts, and flow *' on the furface. If the preflure of the fingers be intire- *' ly removed, the fponge will not only refume what was *' lately forced out, but attract an additional quantity. As *' the fponge in its rarer ftate will naturally attraft and *' abforb more water ; and in its denfer ftate will naturally " attract and abforb lej's water ; we may call the quantity " it abforbs in either ftate, its natural quantity-, the ftate " being confidered." The dotlor then fuppofes, " that what the fponge is to " water, the fame is water to the eletlric fluid ; — that *' when a portion of water is in its common denfe ftate, " it can hold no more elcttric fluid than it has ; if any be " added it fpreads upon the furface." He adds, " when *' the fame portion of water is rarefied into vapor and forms K 2 "a cloud, * A body is faid to be clcflrically charged, whenever it h:.s clUier mari or Irfi than its na- tural cjuantity of elciSlric matter. 76. T H E O R Y OF " a cloud, it is then capable of receiving and abforbing a- " much greater quantity, as there is room for each parti— " cle to have an eledric atmofphere. Thus v^-ater in its " rarefied ftate, or in the form of a cloud, will be in a " negative ftate of eleftricity ; it will have lefs than its " natural qriantlty-, that is, lefs than it is naturally capable *' of attradling and abforbing in that ftate*." The foregoing paflages I have copied 'verhathn from that celebrated eled;rician, as I purpole in the courfeof this, efl!ay to avail myfelf of his idea of the fponge, in order to illuftrate a dlff^erent theory of thunder clouds, which I now beg leave, though with diffidence of my own judgment, and v^ith all due deference to that of fo great a man, to fubftitute in the room of the foregoing ; which I muft con- fefs at firft fight carries great appearance of probability with it, and is highly corroborated by the curious and beautiful experiment the doctor made with the lllver cann,^ brafs chain, and lock of cottonf . But in reading dodor Priejlley''% hiftory of elecflricity, fome thoughts of fignior Beccar'ia occurred, which fatisfi- ed me that this hypothefis, however ingenious and plau- fible, was infufficient for the purpofe of accounting for the rife and phenomena of thunder ftorms, the frequent ex- tent and violence of which feem to require a more general caufe than that hinted above, to fupply them with fufficienc quantities of cledric matter. " Confidering the vaft quantity of eletftric fire that ap- " pears in the moft fimple thunder ftorms (fays dodtor " Prieftly j) fignior Beccaria thinks it impoflible that any " cloud, or number of clouds, fhould ever contain it all, " fo as either to difcharge or receive it.. Befides, during " the progrefs and increafe of the ftorm, though the light- *' ening frequently ftruck to the earth, the fame clouds " were * Franklin's Letters, page 119. \ Page 121. \ PHcftley's Hiftoiy of Eleilricity, page 325. THUNDER STORMS. 77, " were the next moment ready to make a ftill greater dif- " charge, and his apparatus continued to be as much af- " fe£ted as ever. The clouds muft confcqucntly have re- " cei'ued at one place the moment that a difcharge was " made from them in another." Signior Beccaria accounts for this vaft exhibition of ele£tric fire from a thunder cloud, by fuppofing that fomc parts of the earth may become more highly charged with the eleiftric fluid than others, and that great quantities of it do fometimes rufhout of particular parts, and rife through the air into the higher regions of the atmofphere ; other parts of the earth becoming cafually deftitute of their na- tural quantity of the fluid at the fame time, and ready to receive it : That a chain of clouds nearly contiguous, or a fmgle cloud extending from one of thefe regions to an- other, in an oppofite ftate, might ferve as a conductor or conduftors to reftore the eledlric equilibrium between them, which would equally caufe thunder and lightening in both regions, and throughout the intermediate clouds*. Here dodlor P;7^/t7Juftly obferves, that " the greateft diflicul- " ty attending this theory of the origin of thunder ftorms " relates to the colleBlon and infulation of eledric matter " within the body of the earth." With regard to the col- lection^ the dodlor obferves that his author " has nothing ■ " particularly to fay :" Nor indeed without a previous in- fiilation of thofe parts of the earth which may be concern- ed in the produdlion of the phenomena, can any fuch col- lection take place. Now if we confider that in order to have two regions of the earth thus infulated, and of fuffi- cient dimenfions, one to fupply, and the other to receive the quantities of electric fire difcharged during one thun- der itorm of any extent and continuance, the parts infu- lated mufi: be not fuperficial regions, but muft reach to a confiderable depth; and we muft fuppofe, with dodtor Prieftley, " that the eledlric matter which forms and ani- " mates the thunder cloud, iffues from places far below " the » Ibid. . 78 T H E O R Y OF " the furface of the earth, and that it buries itfelf there*." But, with deference to the judgment of that unwearied friend to fcience, I apprehend that i'uch an infulation is hardly confiPcent with that diftribution of condudlors, efpecially of water, which provident nature has made through all parts of our globe; the higheft mountains be- ing furnilhed with internal ii^nngs and fountains, and ■watered external/)' by rivulets, which derive their origin from condenfmg mills or melting fnows upon their lum- mits : While the furface of the earth in general, not ex- cepting the moft fandy deferts, affords fupplies of water to thofe who will be at the pains of digging for it. If then the vapors which conftitute the cloud are, of themfelves, incapable of furnifhing fuch quantities of eledtric matter as are neceffary for the repeated difcharges in a fevere thun- der ftorm, as fignior Beccaria thinks they are, and as feems to me indubitable ; and if the infulations of large portions of the furface or exterior parts of the earth, which rre ab- folutely neceffary to fupport Beccana\ hypothefis, cannot take place ; which, how they can in our terraqueous mafs, is difficult to conceive, confiffently with the hitherto dif- covered properties of the eledric fluid : We muft feek for fome other fubflance in nature which may be capable of affording thofe reiterated fupplies, of that powerful element which are vifually exhibited in ^ thunder ftorm. This I prefume, we fhall find in the atmofphere over our heads; not in the 'vapors which float therein, but in the air itfelf ■which fuftains them. Air is by eledricians juftly clafled \\ 1th eleSiric fubftan- ces, as it jpoffetfes the fame general properties in common with others of that denomination, particular inftances of which may occur in the following pages ; wherein I fhall endeavour to prove, I. That the eledric capacity of air is lefTened by con- denfation. II. That this capacity is increafed by heat. Premifing * FricJlley, page 335. THUNDER STORMS. 79 Premlfing that by nir I here intend that fluid In its com- mon comprcfled ftate with us near the furface of the earth; and by its /^Idclric capacity.^ that ftate of it which dilpofes it, under any circumftances whatever, " to atlraft, abforb and retain," what do£tor Franklin calls its natural quantity .^ or the quantity which is natural to it in that {late. I. I fhall endeavour to prove that the elcciric capacity of air is leflened by condenfation. That a change of denfity in air produces alfo a change in its electric capacity (as above defmed), follows from fome experiments of monfieur de Faye and dodlor Priejlley., the former of whom found, upon repeated trials, that no elec- tricity could be excited by the friction of a glafs tube in which the air was condenfed*. The doftor, repeating the experiments with fome variation, found, that when one additional atmofphere was forced into the tube, the elec- tricity excited by rubbing it was fcarcely difcernable. Now, though the efFedl was a fufpenfion of the operation of the excited tube 'without^ the caufe was evidently the condenfed ftate of the air "within ; which may be accounted for if we conlider, that although it is certain from many experiments that glafs is abfolutely impermeable to the electric fluid, infomuch that it cannot force its way through a pane of glafs, or the fides of a phial, without breaking the glafs, as was the cafe in thofe fpontaneous difcharges~ of feveral of the jars in the eledlrical battery mentioned by do€tor FrieJilLyl ; yet it is as certain, that this impermea- bility of the glafs to the fluid itfelf, is no obftrudion to the operation of that repellent power upon which the vi- fible effedls of this element feem principally to depend; which power undeniably ails from one flde of the glafs, through the very fubftance of it, upon the fan-3 fluid on the other fide, provided there be any other fubftance on that fide capable of receiving it when thus repelled. This is the cafe in the LeyJen experiment in every form in which it can be made; the charge given to one fide of tliC * Page 50. t Page 489, So T H E O R Y OF the glafs, repelling and throwing off an equal quantity of the eledric fluid from the oppofite furface, through the non-eledric coating in contact with it; nor can any charge be given to either fide without a proportional difcharge from the other. In like manner, when an uncoated tube is excited by fri£tion, a quantity of the fluid, equal to that which is excited and condenfed upon the outer furface, is thrown out from the inner, provided there is any fub- ftance within in a capacity to receive and abforb it, with- out which no excitation can take place. " A glafs tube, " out of which the air is exhaufted, difcovers no figns of *' eledtricity outwards*," there being no fubftance within capable of receiving and abforbing the fluid from the in- ner furface, which though repelled from it inwards dur- ing the operation, yet returns to it again inftantly upon a cefl'ation of the action of the rubber without. But upon a readmifhon of air the excitation is eafy, and is attended •with the ufual effed:s. Air then, which is the only fub- ftance admitted (excepting perhaps a few ftraggling va- pors which float in it) receives and abforbs a fufficient quantity of the eledlric fluid from the inner furface to per- mit an excitation of the tube which contains it. But as we have feen that air, when condenfed within, prevents the vifible effedls of an excitation, equally with a total va- cuity, we may adopt the idea of doftor Fratikiin, ?}iutaiis mutandis^ and conlcude that " what the fponge is to water *' the fame is air to the ele£tric fluid :" At leaft that this ca- pacity of air if lelfcned by condenfation in a manner, not indeed perfeftly fimilar, but, fomewhat analogous to that in which the capacity of a fponge to receive and retain water is leflened by compreflion. Agreeably to which idea, the condenfed-air within the tube, having its eledlric capacity filled and even crowded with the eledric matter, will re- ceive none from the inner furface, which, on the contrary, is thereby prevented from being forced out of it, without which f Prieftley's hiftory of cicifliicity, page 550. THUNDER STORMS. 8i which none can be forced Into or condenfed upon the out- er furfece, fo as to exhibit any figns of electricity; as ob- ferved before, II. I fhall endeavour to prove that the eledric cat^acity of air is increafcd by heat. *^-* This aUb appears probable, at leaft, from the above cited experiments of do£tor Prieftley ; for after the air in his tube had had this capacity fo far diminilhed by condenfa- tion as not to permit an excitation without, that capacity, together with the coniequent excitability of the tube, was reftored by the adion of heat upon the included air. " Re- " peating my attempts (fays he) to excite the tube above " mentioned, I found that, after very hard rubbing, it be- " gan to ait a little, and that its virtue increafed with the " labour. Thinking it might be the warmth which pro- " duced this efFetSt, I held the tube to the fire and found " that when it was pretty hot, it would adl almoft as well *' as when it contained no more than its ufual quantity " of air*." In page ^^^^ dodlor Priejlley tells us that fome of his eledlrical friends were of opinion, " that the reafon why " a tube with condenfed air in it cannot be excited is, that " the denfe air within prevents the eledric fluid from be- *' ing forced out of the infide of the tube, without which " none can be forced into the outfide ; and that heating " the tube makes the air within lefs eledlrical." That is, as I conceive their meaning, puts it in a capacity to re- ceive and abforb more of the eledlric fluid than it could other wife do in that condenfed ftate. The doctor indeed queries by way of objeftion to the foregoing folution, — " How upon this principle can a folid flick of glafs be ex- " cited ?" To which I would anfwer, that polhbly, when a folid flick of glafs is excited, as much of the eledtric fluid may be drawn out of one fide of it as is thrown into, or con- denfed upon the other; if fo, although it may fhe.v equal figns of electricity on both fides, yet one fide will be in a L pofitive . * Page 551. \ 82 T H Fi O -R y OF pofitlve, the other in- a negative ftate ; when it will ex- aftly refemble the curious ftone called the tourmalin., by Ibme lapis eleSlricuSy which doctor Pr'iejiley fays * " has *' always, at the fame time., a pofitive and a negative elec- *' tricity ; one of its fides being in one ftate, and the other " in the oppofite;" which does not depend upon the ex- ternal form " of the ftone." But the truth of this foluti- on muft be determined by future experiments. That the eleftrical ftate of the air is liable to be affefted by heat, is further evident from a courfe of experiments which were made by the abbe Mazeas, with an apparatus that was conftrufted folely with a view of determining the eleftricity of the atmofphere, anno 1 753 1- With this ap- paratus the abbe obferved, that from the i yth of June, when he began his experiments, the eledtricity of the air was fenfibly felt every day, f?'o??i fun rife till fcven or eight 0^ clock in the evening., when the weather was dry ; but that in the drieft nights of that fummer he could difcover no figns of eledlricity in the air, nor till the morning, when the fun began to appear above the horizon, and that " they vaniftied again in the evening, about half an *' hour after fun fet ;" and further, " that the firongcfl " common ele£tricity of the atmofphere, during the fum- " mer, was perceived in the month of fnly on a ^)ery dry " day, the heavens being very clear, and the fun extreme- " ly hot.'' Now, as this electricity of the air was fenfible only dur- ing day light., no electricity being difcoverable therein even in the drief flights, and as the air exhibited the fronge/i figns of electricity when the fun Ihone extreinely hot ; is not the conclufion unavoidable, that heat fomehow affedts the eledtric capacity of air, either enlarging it, and there- by difpofing the air to attract, receive and abforb greater quantities of eledtric matter than it is capable of abforbing in its natural ftate ; or fuperadding to its natural quantity more than it can abforb, and thereby difpofing it to throw off * Page 399. t P»g« 343. THUNDER STORMS, 83 off the redundancy upon any objedis which may be in a lituation to receive it ? One or the other feems neceflarily to follow, but the former is moft agreeable to do£lor Prieftley\ experiment of the condenfed air in the tube a- bove mentioned, and is perfedlly confonant with the ob- fervations of doftor Franklin., Mr. Kinnerjley and others, that thunder clouds are generally in the ncgat'fve ftate of electricity*. But more upon this head hereafter. I would however obferve here, that many, and perhaps all other eleflric fubftances, even the moft firm and folid, as well as air, are liable to have their elecflric capacities thus di- verfified by heat, more particularly the tourmalin above mentioned. But as, in treating of the properties of this flone, dio€tox Priejlley has thought it deferving of a diftindt fe£lion in his eledlric hiftory, to that I fliall refer the read- er for a particular account of them f ; wherein he will find a difcovery inade by MelTrs Cantoji and TVi[/bn, that thefe properties are not peculiar to the tourmalin, but that many gems have a natural difpoiition to afl^ord the fame appear- ances ; from whence we may conclude as above, by ana- logy, that all electric fubftances are, more or lefs, affedted in like manner, by the fame caufe. But to return to the fubje£l. If from the foregoing confiderations the reader fhould be fatisfied, that the electric capacity of air, in its con- denfed ftate in the lower regions of the atmofphere, is li- able to be diminiflied by a further condenfation, and that, CiVteris paribus., it is increafed by heat et vice verfa ; the folution of the phenomena of thunder and lightening, to his latisfaftion, upon ele^Slrical principles, will perhaps be no diflicult tafk. For let us conceive a region of the atmofphere, extend- ing over a large tradt of country, to be rarefied and hcat- L 2 ed * Epitome of Phil. Tranf. Gent. Mag. Sept. 177J, page 447. Mr. Henley thinks cold eletTLrifies the atmol'phcre pofitively, and thence conjcrtiircs that heat cledlfihcs it negi.ively. •His toiicUifioiis are ioundtd upon a courl'c of experiments. t Page 29 ?• 84 THEORYoF ed during a. hot fummer's day, not only by the paflage of the fun's diretfl rays through it, and by the refledlinoof thofe rays from the furface of the earth into it; but chiefly, by the communication of the heat acquired by that furface to it : The eleSiric capacity of that region of air would be incrcafed, both on account of the heat it undergoes, and of the rarefacftion confequent upon that heat : It will then have lefs than its natural quantity-, or the quantity it is naturally difpofed to receive and abibrb in that ftate; it will confequently be, in the language of eleftncians, negatively eledlriled, or in a craving ftate, requiring and forcing fup- plles from all fubftances capable of affording them, pro- vided it be itfelf in a condition to receive them. But, however craving, it cannot receive thofe fupplies from the neighbouring regions of the atmofphere, while thofe re- gions feverally remain in the ftate of pure air, even fup- pofing the latter to poflefs more than iht'ir natural qiianti~ ties-, and thereby as much difpofed to impart, as the for- mer is to receive them, without the intervention of non- eleftric condudlors ; and that, owing to the impermeability of air, as fuch, to the eledtric fluid. This I fhall endeavour, I. To illuftrate by experiments made with glafs. 2. To prove by experiments made upon air itfelf. I. If a pane of glafs be coated on both fides, by the ap- plication of plates of tin to them, the glafs may be charged in the fame manner as the Leyden phial ; when, after the removal of the plates, no difcharge having previoufly taken place, both fides of the glafs will remain charged, one pofitively, the other negatively ; the former having more than its natural quantity., the latter being proportion- ably deficient, and in a craving ftate. Thefe ftates both furfaces will obftinately maintain for a long time : Nor do I know of any method of reftoring the electric equilibrium between them, but, either to immerfe the pane in water or fome other non-ele£tric fluid, which will do it inftantly, and filently j or to reapply the metalline coatings to both fides THUNDER STORMS. % fides as they were placed at flrfl:, with a good condudtor introduceci between them, which will aniwer the fame pur- pole, and be attended with an explofion, or fmart ipark and fnap ; or laftly,- to place it in a fituation where it may be expoled to air replete with moift vapors, where, after fome time, the vapors will, by condenfnig upon each fide, furniih it with a moillure equivalent to a non-ele£lric coat- ing, while the vapors which remain in the furrounding air will, by continually impinging upon and receding from the two furfaces, at length reftore both to their natural ftate. It is evident from the foregoing experiment, F'lrJ}^ That the charges refide in the glafs iti'elf, as they remain after the coatings are removed. Secondly., That the oppofite fides have a very Arong propenfity, one to give, the other to re- ceive the fluid, and thereby to reftore the electric equili- brium between themfelves; which is done with violence, as obferved above, when they are put in a condition of do- ing it by the reapplication ot the metalline coatings, with a condu£lor between them, and Lajllvy That notwithftand- ing the" violent propenfity in the fides of the glafs, to re- ftore themfelves and each other to their natural eleftric flates, and the fmall diftance between them, they can ne- ver effect it, without thelntervention of non-ele£lric con- dudlors. 2. I fhall now fhew by other experiments, that difi'erent regions or ftrata of air mnv become charged, both pofi- tively and negatively, in the fame manner as the fides of the pane of glafs were in the foregoing; and that the effe£ls of fuch charges are precifely the fame. Melfrs Wilkie and JEpinus at Berlin., having the hint naturally fuggefted to them by a previous courfe of experi- ments, endeavoured to give the eledlrical fhock by means of rt/r, in the fame manner in which it may be given by glafs \ " in which after making feveral attempts (fays doc- " tor Prieflley*) they at length fuccecded, by fufpending " large: ' Page 243, 86 THEORY OF large boards of wood covered with tin, with the flat fides towards one another, and at fome inches afunder. For they found, that upon eledlrifying one of the boards pofitively, the other was always negative. But the dif- covery was made complete and indifputable by a perfon's touching one of the plates with one hand, and bringing his other hand to the other plate; for he then received a fhock through his body exadtly like that of the Ley- den experiment. With this plate of air, as we may call it, they made a variety of experiments. The two me- tal plates, being in oppofite itates, ftrongly attracted one another, and would have rulhed together if they had not been kept afunder by the firings. Sometimes the eledricity of both would be difcharged by a ftrong fpark between them, as when a pane of glafs burfts with too great a charge. A finger pat between them promoted the difcharge, and felt the Ihock. If an eminence was' made on either of the plates the felf-difcharge would al- ways be made through it, and a pointed body fixed up- on either of them prevented their being charged at all." To the foregoing relation of the experiments themfelves, I fliall fubjoin the conclufions drawn from them by the cu- rious electricians who made them, in the words of dodtor Priejiley-, viz. " The ilate of thefe two plates, they " [M^il~ kie and JEpinus) " excellently obferve, juftly reprefents the " ftate of the clouds and the earth" (and perhaps of dif- ferent clouds at various heights one over another) " dur- ing a thunder ftorm; the clouds being always m one flate, and the earth in the oppofite; while the body of air between them anfwers the fame purpofe as the fmall plate of air between the boards, or the plate of glafs be- tween the two metal coatings in the Leyden experiment. The phenomenon of lightening is the burfting of the plate of air by a fpontaneous difcharge, which is always made through eminencies, and the bodies through which the difcharge is made are violently fhocked.'* As THUNDETv STORMS. 87 As in the former experiment made with the pane of giafs, the charges, both pofitive and negative, refide in the glafs itlelf, and not in the coatings, thofe remaining after thefe are removed; fo in the Litter, which is completely- analogous to it, the charges are accumulated and refide in the air fituated between the boards, and not in their tin linings, which ferve only as conductors, to diftribute the fluid equally over, or to convey it equally from, the whole furface of air which is limited by, and in contadl: with them, on either fide ; whereby the whole of each furface may be equally charged at the fame time, or difcharged by the fame explofion. If two or more regions of the atmofphere, when free from vapors, become thus differently electrical in their ftate and capacities, which, that they may, from the heat and confequent rarefaction in a fummer's day, we have al- ready feen, and perhaps from a variety of other caufes to us unknown; and if from the contrary currents of air which frequently take place at different heights, they fliould perchance become fituated one over or adjacent to another, like ftrata of minerals within the bowels of the earth; what the metalline coating is to the pane of glafs, or the tinned boards to the plate of air in the laft experi- ment, the fame would clouds, formed and floating therein, be to thefe regions of air; the eleClric equilibrium between which might be reftored through their intervention, either by fpontaneous difcharges through the pure air between them in fevere flafhes of lightening or through the falling drops of rain, which in their I'ucceffive defcent form a chain of natural conductors between one region of the air and another, and betwixt each of them and the earth; the pafTage of the eleCtric fluid through which would alfo he- attended with lightening and thunder, but not fo fevere as when the difcharge is made through the pure air; the moft fatal lightening ufually preceding the fall of the rain. It $8 T H E O R Y OF It is not uncommon, during the rife and progrefs of a thunder ftorm, to fee different fets of clouds, at various heights in the atmofphere, moving promlfcuoufly in all directions, as though they were impelled hither and thi- ther by contending winds; when probably the whole phe- nomenon arifes from the different eledrical ftates of the regions of the air in which they float; as they approach one or other of which, they are attradcd or repelled, and move accordingly, communicating, receiving, or tranfmit- ting the eledlric fluid, to or from them refpectively, as they may be either deficient of their natural quantity, or poffefs a redundancy of this fluid. And as in the experiment of Meffrs Wilkie and JEpinus mentioned above, the two tin plates with the boards they covered, would have ruflied together had they not been kept afunderby the fl:rin;^s, fo thefe clouds floating freely in air, and being at liberty to a£t upon every impulfe, gradually coalefce, reftoring the eledtric equilibrium to the neighbouring atmofphere by repeated difcharges as they unite*; till at length they form one denfe mafs of humid vapors, which precipitating in a heavy fliower of rain, refrefh the thirfty foil, leaving the atmofphere above in a homogenous electric ftate, calm and ferene. How thefe clouds are generated, formed, and adapted to thofe grand purpofes in the oeconomy of nature, is next to be confidered: In profecution of which inquiries I {hall fubmit the following obfervations to the candor of the reader. Whatever the immediate caufe of evaporation may be, it is certain that the fuperficial moiflure of all bodies is perpetually exhaling in vapors, which afcend into the higher regions of the atmofphere, where they gather and .are formed into clouds, and at length recondenfe, defcend- ing - * Tt is certain that in moft thunder ftorms the fiafhes of lightening are chiefly difcharged ^rom cloud to cloud, very few, and frequently none at all taking place between the cloud and tlic earth. THUNDER STORMS. Sc) ing in dew, mid or rain upon the furface of the earth from whence they fprang. Thefe vapors are ellher detached in ftreams from the humid ground by the influence of the fun, or thrown off" by the perfpirations of thofe infinite muhitudes of animals and plants which cover the face of the earth*, or fupplied by evaporation, from the ocean, or other grand collections of water. Ignorant as we are of the nature of thefe operations, and of the manner in which they are performed, it is natural to fuppofe, that the vapors themfelves afcend in the fame eleClric ftate, whether pofitive, neutral or negative, with the fubftances from which they arife. Accordingly fignior Beccar'uit in making fome of his experiments, obferved, that " fteam rifmg from an eledlrified eolipile diffufes it- " felf with the fame uniformity with which thunder clouds " fpread themfelves and fwell into arches, extending itfelf " towards any conducing fubftancef ." This ftream then was eledlrified as well as the eolipile from whence it pro- ceeded. The fea muft neceffarily be fuppofed, in common with the whole terraqueous mafs, to contain juft its natu- ral quantity of the eleilric fluid, and no more: We may therefore conclude that both the vapors which arife imme- diately from it, and the air which fuftains them, and from its fituation enjoys a more equable temperature, than that over the land, are in the fame eledfrical ftate with the fea itfelf, containing neither 7nore nor lej's than their natural quantity. Confidering the vaft extent of the ocean, and the com- paratively fmall degree of moillure of which the dry land is fufceptible, we may conclude, that a very fmall proportion of the clouds which are formed in the atmofphere are ex- haled from the latter, and that the ocean is the grand fource from whence they principally derive their origin. M Our * See Uales^s vegetable ftatlcs, and Chambers's cyclopedj under the word, Pcrfpiration. •\ Priellley's HilTory, page 327, 90 THEORYoF Our fenfcs accordingly convince us that the fea-air is al- ways replete with moill vapors, even when its natural tranfparency is not in the leaft interrupted by them. Hence in a hot fummer's day, when the wind fuddenly flilfts from weft to eaft, we immediately perceive a chill from the fea-breeze; and fometimes long beiore the ther- mometer indicates a change in the temperature of the atmofphere. Thefe vapors, when they firft arife from the fea, are generally fo nearly of the fame denfity with the furrounding and contiguous air, that the rays of light in pafling through them, undergo no fenfible change in their refradion; they are therefore at firft generally invifible, but when the weather is extreamly cold, and the air of confequence uncommonly denfe, they are always vilible, and appear like a fteam arifing from boiling water*. Not that vapors afcend moft copioufly in the coldeft feafons, which feems contrary both to reafon and experience; but that the diff^erent denfities of the air next the furface of the water, and of the vapors which afcend in it, render the latter vifible, by the irregular refradlions of the rays of light in pafling through them. For the fame reafon our breath is vifible in the winter, but not in warm weather. Let us now fuppofe the atmofphere, on a fummer's. morning, to be all around in a honiogenous ftate, as in- dicated by a cloudlei's fky and a dead calm. As the fun rifes on the eaftern coafts of America, and warms and ra- refies the atmofphere eaftward, the rarefied air naturally afcends, and a current of air as naturally iiows thither from the oppofite quarter, which is but juft emerging from the cool {hades of night, to fupply its place. The confequence of which is a light wefterly breeze. As the fun afcends higher, the air over the land becomes heated and rarefied, both by the pafTage of the fun's diredt and refiecled rays through it, and by the reverberation of the heat acquired from * This is always the appearance in a clcaij ftill morning, when the mercurj- in Farenhcit's. thermometer i^ at o, or btlow it. THUNDER STORMS. 91 from them by the furface of the earth; till at length that whole region of the atmofphere has its elcdtrical capacity enlarged, thereby becoming negatively electrifed, or in a craving ftate, as obferved before. On the contrary the fun's rays which fall upon the furface of the fea, efpecially when ruffled by wind, chictiy enter that tranfparcnt me- dium, in which they are refraded and irrecoverably ab- forbed; very few, comparatively, being refledled; whence very little heat can be reverberated from that element to warm the incumbent air, which is fenfibly affected only by the paffage of the fun's dire£l rays through it, unlefs the weather be calm and the furface very fmooth*. Befides, it is colder at fea than afliore in the fummer feafon, when, and when only thunder fhowers are frequent, and indeed warmer in the winter, for the following reafon, viz. as the fea is every moment changing its furface, neither heat nor cold can affeft it fo foon as they do the furface of the earth, which continues the fame. The air over the land, when thoroughly heated and ra- refied, naturally afcends into the higher regions, while the denfer air from the fea neceflarily flows in and takes its place. Hence, probably, the eafterly winds which ufually fpring up near the middle of the day, after a fultry morning. This body of warm air afcends till it arrives at that re- gion of the atmofphere in which thunder clouds are form- ed ; while the vapors which are wafted to the continent by the eaftern current, being attracted by this now fupe- rior air which demands a fupply of the ele<5tric fluid, con- M 2 tinually * In a perfect calm the furface of tlie fea at^s like a mirror upon tlie fun's rays, llrongly re- verberating them back into tlic atmofphere, ivhcn the heat is as fcufible upon water as upon the dry land. But whenever that furface becomes agitated and broken by the force of wind aifling upon it, thofe rays, by perpetually impinging upon an infinite variety of new formed, fluiftuating furfaces undergo innumerable rcfraiflion^, in all dire(ilions, whereby they are ab- iorbed and loft within the fluid mafs in fome proportion to the violence of the agitation. Ac- cordingly when the w-eather is ferene and calm, the furface like a looking-glafs reflects the phe- nomena of the Iky over head ; upon the firft fpriuging up of a breeze it changes to a light blue, •which deepens to a fine fky-blue as the wind rifes, to a deeper fea-green in a briik gale, and to a fullen blackncfs in a ftorm, excepting where the waves are interfperfed with white heads of foani, which, by contrail, only render the fcene more gloom;'. 92 T H E O R Y OF tinually afccnd till they arrive at it, leaving the denfer air, with which they were firft connected, behind. As thefe vapors move freely through and mix with air, they eafily infmuate themfelves between the particles of that fluid, and unite Vv^ith it, whereby every particle of air which, from the caufes aforefaid, is become in any degree defti- tute of the quantity of electric matter which is natural to it in its prefent ftate, may and will attratl and attach to itfelf one or more particles of this vapor, and thereby fur- nifli itfelf with a non-ele£tric coating, and thus become qualified to receive from any neighbouring obje£t fuch a fupply of the elecftric fluid as its ftate may demand. Thus provided, this body of air, together with the va- pors which are more or lefs attached to every particle of it, will conftitute a denfe cloud ; and as the air itfelf was before (by fuppofition) in a craving or negative ftate of cledlricity ; and as the vapors are prcfumed to have arifen from the ocean in their natural or neutral ftate, the whole body of a cloud formed by them will ftill be in a negative ftate, and thereby conftitute a complete thunder cloud ; which when formed, if uniform in denfity and contexture, fliould it be attraiited within thejiriking dijiance from any objedl ftanding upon the earth, would have its eleftric equilibrium rcftored at once by a flafti of lightening dart- ing from the earth : Or Ihould it pafs near another cloud in a diiferent ftate, the flafti would reftore an equilibrium between the two clouds. That a body of air, either in a pofitive or negative ftate of electricity, while pure, ftiould be incapable of commu- nicating its furplufage of the electric element to, or re- ceiving ftapplies from the neighbouring regions, though in a contrary ftate ; and that the fame air, when replete with watery vapors, may be reftored to an equilibrium throughout its whole extent by an inftantaneous difcharge, may yet require fome further evidence before it be admitted. But, THUNDER STORMS. 93 But, as the particles both of air and vapor are feverally too minute to fall under our notice, I fliall endeavour to illuftrate by analogy what cannot be diredly demonftrated by experiment. In order to this, I fliall firft give a ge- neral defcripticn of, and then fubjoin fome obfervations upon dodtor Prlejlley''% electrical battery. This battery confiiled of fixty four cylindrical glafs jars fixed in a fquare box ; the jars were coated within and without with tin foil, and the floor of the box was cover- ed with the fame, a\ hereby the outfides of all the jars formed but one continued eledlrical furface. In like man- ner, by means of fmall brafs bars extending over the mouths of the jars in their feveral ranges, and by wires v;hich conne£ted the feveral bars, together with others which defcended from them, communicating with the in- ner coating of each jar, their interior furfaces were fo connected as to form, in the fame fenfe, but one furface. Thus conftrudted, the whole battery is capable of being equally charged in every part at the fame time, and of be- ing difcharged throughout by the fame explofion. Here I would obierve, that if, inftead of the metalline coatings, the jars were filled with water to the fame height with them, and were immerfed in the fame order in a fquare veflel of water to an equal depth, the bars and wire remaining as before, the fuccefs of all the experiments made with them would be the fame as above. Let then a battery be conilruCled and charged in this form ; after which let the bars and wires aforefaid be removed, and the water contained in the jars be decanted off by glafs fyphons, and let the water be drawn off from the veflel in which they ftand. It is evident from the experiment of the charged pane of glafs already mentioned, and other experiments recited in doctor Franklin's letters, that thefe jars will remain Je'verally charged, as they were jointly before. They may now, when dry, be taken out and handled at pleafure with fafety ; nor can they be eafily re— llored; 94 T H E O R Y o? ftored to their natural ftates, but either by immerfing them fingly under water, or by replacing the whole apparatus and filling both the jars, and the box which contains them, with water as at firft, and introducing a metalline conduc- tor betwixt the water without the jars and any one of the wires which connedt their infides ; then the whole will be inftantly difcharged v/ith an explofion*. To apply thefe obfervations to the prefent fiabjeft, we may regard every particle of a body of puref, but inci- dentally eleftrified air, in the fame light with one of the jars in the battery aforefaid, which, after having been charged, is deprived of its adventitious coatings : Each particle, like one of thofe jars, will retain the ftate it may happen to be in, fo long as it remains deftitute of a con- ducting appendage. But when, and by what means foever, a fufficiency of moift vapors fhall become interfperfed amongft thefe particles of air to furnifh them feverally with non-eledtric coatings, and by the nearnefs or contiguity of thefe vapors to form a communication from one to another throughout the whole, they will then be in the fame con- ne(ftcd ftate with the jars in the battery, when complete in every part, and charged ; and like thofe jars be the particles ever fo numerous, they will be in a capacity of jointly receiving or communicating the ele(ftric fire. And as, by the addition of jars in the conftruftion of the bat- tery, the explofion at the difcharge may be increafed inde- finitely, fo will the violence of the explofion from a thun- der cloud be increafed in proportion to its extent, and to the multitude of aerial particles together with their ap- pendant vapors of which it confifts, and which are fo con- nected as to be capable of uniting in the fame difcharge. But as a thunder cloud is not ufually formed at once, but by degrees, fmaller clouds generally forming themfelves in * Thefe cMperiments I never faw particularly made, but the conclufions ncceflarily follow from fome which I have feen, as well as from thofe pointed out above. ■j- Pure as to the purpofes of electricity, or free from condu6ling vapors ; perhaps pure ele- mcntarj' air is not to be found in our atmofphere. THUNDER STORMS. 95 in fcparate parties before they join the main body ; and as the eledtrical ftates of thefe clouds may be very different from each other, from the different electrical ftates of thole parts of the atmofphere in which they gather ; the general equilibrium of the atmofphere over a country can- not be reftored by a fmgle difcharge, but fucceffive flafhes will dart from cloud to cloud, and betwixt thefe and the earth, till at length the whole colleded mafs of vapor is fpent and diffolved in rain. Here a common obfervation naturally occurs, viz. that frequently after a f^afh of lightening a Hidden fliower de- fcends in large drops. The mutual attradlion between the vapors and the air, when in this eledrlcal ftatc, is fufhcl- ent to fuftain the former, notwithftanding that they arc by this attraction greatly condenfed, being as it were forced into a phyfical contact, both with the particles of air, and with each other*. But as foon as the air is reftored to its natural electric ftate by a fiafh of lightening, this attradioa ceafes, and the vapors precipitate by their own fpecific gravity in a heavy fhower. Long and extenfive calms, in certain latitudes and fea- fons, take place upon the ocean, during the continuance. of which, the heat is Icarcely tolerable. (See note, page 91.) Where thefe take place the air will naturally undergo the fame changes, in its denfity and electric capacity, as the air over the land does in the fummer feafon, and, when fufliciently * A gentleman of my acquaintance, who is both intelligent and curious, informed me fonie years fince, that he was once upon the top of a mountain in Spain, upon which a thtmder cloud; gathered ; that as foon as tlie cloud became infulatcd from the mountain it difchar^ed a vio- lent tempeft of thunder and lightening upon the plains hclow ; that he never was fo tJiorough- ly fo;'.ked in the moll \Iolent Hlower as when in the body of this cloud, though without a drop of rain, feeling as if he had been immerfcd in a river. This idea is further juftified by tlie fo- lid appearance of tlic clouds that rife in the weft on a hot fummer's day, compared with thofe, which float in the atmofphere at other fcafons ; which fhews a manifeft diflerence in their den- ■ fity and contexture : And wlien we obferve attentively the feveral part* of a thunder cloud, the ; dillindlnefs of their borders and their Iwelling furbeloe^; how flrongly they refletft the rays of the fun, thereby exhibiting the moll vivid lights and deep contralling fhades ; and on the other ■ hand obferve the beautiful eflecls of their refraifiive power in the intenfe golden (kirts which adorn the rifing cloud with a fetting fun behind it; we muft neceflTarily conclude, that, al- though the vapors of which fuch clouds confift are collecled and condenfed in higher regions of.- the atmofpliere than arc thofe which ufually form clouds at other feafons, yet their denfity andi frccific gravity is much greater ; and they derive their fupport from the eleClric principle. . g6 THEORYoF fufficiently heated and rarefied, will In like manner afcend, its place being fupplied by the denfer air from all quarters without the limits of the calm. This heated and confe- quently (granting the principles of the prefent theory) eledlrical air, when raifed to a certain height in the at- mofphere, may become as well adapted to the formation of a thunder cloud, from the vapors which are perpetual- ly exhaling from the fea, as the air over the land under the like circumftances. Wherefore, in ibme latitudes in all feafons, and perhaps in all latitudes in different feaforis of the year, thunder ftorms may as well happen at fea, even at remote diftances from land, as alhore. I now proceed to confider an objedion which may be raifed againft the foregoing theory, which I fhall firft ftate in its full force, and then endeavour to give a fatisfadlory anfwer to it. Objecfion. If the ele£lrification of that body of air in •which a thunder cloud is formed depends upon the heat it has previoully acquired, whence is it that thunder ftorms are frequently attended with fhowers of hail, which hail is fometimes fo large as to indicate its defcent from the coldeft regions of the atmofphere ? Anfwer. Sir Ifaac Nexvton aiferts from experiments of his own, that " the denfity of the air in the atmofphere of *' the earth is as the weight of the whole incumbent air." Confequently the air gradually decreafes in denfity from the furface of the earth to the top of the atmofphere. The body of air which is fuppofed in this theory to be qualifi- ed by the adion of heat upon it, to become a proper fub- Jlration for the formation and fupport of a thunder cloud, is thereby expanded and rarefied, and thence becomes fpe- clfically higher than it was before: It therefore afcends till it arrives at that height in the atmofphere at which the air is naturally, from its fituation, of the fame rarety with itfelf ; and there it refts in equilibrio. This region is ex- ireamlv cold at ali feafons, as appears from the teftimonies of THUNDER STORMS. 97 of travellers who have vifited the tops of very high moun- tains, even under the line. The greater the heat which this body of air acquires below, the greater degree of ra- refadlion it undergoes, and the higher, of confequence, it afcends in the atmofphere, where the cold is proportion- ably more fevere than is ufual near the furface of the earth. But though it was the heat which it acquired below that firfl; rarefied and expanded it, it will by no means be pro- portionably recondenfed by the cold which it meets with in its afcent ; for as the heat which occafioned its rarefac- tion decreafes upon that account, the prelTure of the in- cumbent atmofphere upon it decreafes as it rlfes, whereby its denfity may, upon the whole, remain nearly the fame ; if fo, may we not fuppofe its electrical ftate aUo, previous to the formation of the cloud, to continue nearly the fame ? For fliould this warm air afcend all together as in a body, without intermixing with the denfer furrounding air through which it rifes, as a bubble of air does in any other fluid, and as this air probably would in a calm feafon, the den- fer parts of the atmofphere eafily giving way to it, till it arrives at that region the denfity of which is equal to its own, where it would be at reft ; ftiould this, I fay, be the cafe, it would not, even in that cold region, cool fo fud- denly as to undergo any immediate change in its electrical ftate, from the natural coldnefs of the region ; neither would it be from condenfation, its denfity remaining nearly the fame, as obferved above. But when the cloud is formed, or rather when a number of clouds are forming In the neighbourhood of each other, and joining their forces preparatory to the tempeft, a ge- neral confufion takes place in the atmofphere; various and even contrary currents of air flowing promifcuoudy hither and thither, as is evident from the vifible irregular moti-. ons of detached parts of the clouds. In this general efl^ort of nature to reftore an equilibrium, fome of thefe aerial currents will probably introduce air, which having been N till 98 ■ T H E O R Y OF till now at a dillance from the fcenc of a£tion, has fuffered uo material change in its natural eleQric ftate* ; and is on the contrary fraught with all the cold which is natural to the region of the atmofphere from whence it came, la falling through this adventitious current of air, the drops of rain, precipitating from the body of clouds above, are congealed into ice, and defcend in hail, which as it falls collcds other fnowy or icy particles round it ; a hail-ftone when it comes to the ground refcmhling denfe fnow with a nucleus or kernel of folid ice in the middle. That the air which this hail-ftone falls through is cold- er than the region from whence it defcends, may be thus proved, viz. If the freezing took place where, and as foon as the vapors were firft fet at liberty by a flafh of lighten- ing, it would be impoflible for them ever to unite into drops, but they muft defcend in the fineft chryftals, an affemblage of which conftitutes a flake of fnow ; the nu- cleus, or proper hail-ftone then muft have been firft a fluid drop, and afterwards congealed in its fall through a colder region than that in which it was formed. It may be further objedled, that a thunder cloud, in the eaftern parts of America, always makes its firft appearance in the weft, over the land, its progrefs being toinmrds the fea; which feems to contradict the fuppofition in the the- ory, that the vapors of which it confifts are chiefly fuppli- t^from the fea. To which I anfwer, i. That a thunder cloud is with us very rarely, indeed fcarcely ever formed in the weft, with- out a fea-breeze fpringing up previoufly from the eaft, 2. That the fea air, as obferved before, always abounds with vapors, although from the caufes already afligned, they are ufually, at their firft rifing, invifible. 3. That the firft appearance of a cloud will always be where the vapors are * This furrofition will he juftiGed by confidering, that fuch is frequently the ftate of the atmofphere, thjt the thunder clouds which are formed in it arc but of fniall extent ; notwith- ftanciing \\hich, the char.ge in tlie ftate of the air occaCoacd by them is perceived to the dif- tancc of many leagues round. THUNDER STORMS. 99 are firft colleded into a body and condenfed, and thereby- rendered vifible, which in a thunder cloud will be in the weft, notwlthftanding the vapors of which it confifts may chiefly have arifen from the fea. 4. That when a thunder cloud is once formed it will be in a ftate of attraiflion with the earth in general, and more efpecially fo with all fub- ftances which are natural condudtors of the electric fluid, fuch as the water contained in rivers, bays, arms of the fea, &c. and by thefe the courfe of a thunder cloud is known to be very fenllbly afFe£ted. But the ocean is the grand objedl towards which its courfe will be direfted; accordingly the progrefs of the clouds is from the weftern horizon, eaftward, be the wea- ther below what it may, not excepting the moft violent eafterly ftorms, which are fometimes, though but rarely, accompanied with thunder and lightening. To the foregoing obfervations I would add, 5. That when an extenfive thunder cloud is forming in the atmof- phere by means of the mutual attra(Sl;ion of the conden- fmg vapors, and the body of ele£trifed air which fuftains and condenfes them, the increafing denfity of the whole compound mafs of air and vapor will, by degrees, occafioa its redefcent towards the earth, from the law of gravity; it will alfo be attracted by, and move towards the ocean, upon the principles of eledtricity ; the cloud will then de- fcend obliquely, in a diagonal between the directions of thefe two powers; and both, continually a£ling upon it, will jointly accelerate its motion. Such a cloud, if denfe and large, would end in a perfedt tornado, either upon the land or water, as thunder ihowers frequently do; fmaller clouds being alfo, ufually, accompanied with gufts or flurries of wind. I fliall here add one obfervation more wliich I have fre- quently made, and which may tend to confirm the fore- going theory, viz. That as the general courfe of the eaftern coafl: of north America is from north-eail to fouth-weft; N 2 the lOO THEORY OF the courfe of a thunder cloud is ufually from the north- weft, with the wind at fouth-eaft, perpendicular to the di- redlion of the coaft, and contrary to each other. Inland feas and great lakes, fuch as are thofe in North- America, may anfwer the fame purpofes in the interior parts of the country, as the ocean does near the limits of the continent ; both by affording the neceffary fupplies of •vapors for the formation of the clouds, and by their attrac- tive influence upon thofe clouds when formed. I now conclude with a few hmts, which I fliall throw into the form of queries. 1. Whatever the primary caufe of evaporation maybe, does not the formation of vapors into diftindt clouds de- pend upon the eleftrical ftate of the atmofphere ? 2. Were the atmofphere always uniformly electrical could we have any rain*; in that cafe, if evaporation be performed independent of ele<^ricLty, fhould we not be invelloped in everlafting fogs ? 3. Mr. Canton fuppofes that the aurora borealis may be " the flaflilng of eledric fire from pofitive towards nega- " tive clouds, throughout the upper part of the atmof- " phere." But as the air is ufually charged more or lefs with vapors, even when perfeftly pellucid ; and as the mofl; remarkable aurora frequently appear without a cloud in the hemifphere, may not this phenomenon be rather occafioned by the " flafhing of eledlric fire," from one region or body of air to another in a different ftate of elec- tricity, through the intervening vapors ? 4. May not thereafon of its ufual appearance In the north and of its flafhing fbuthv\^ard be, that, in every northern latitude, the air to the fouthward is at all feafons of the year, ceteris paribus, more affected by the heat of the fun than the air northward of the fame latitude; and does not this occalion an eledirical current to flow from north to fouth, • Slgnior Bec:arta concludes from experiments, that gentle rains are the effefts of a mcdeiaU, »s thunder fliowers are of a more plentiful, eki^ritit)'. WATERSPOUTS. loi fouth, fo often as the above mentioned circumftances con- cur, though with fome interruption from the irregular dif- pofition of the conducing vapors; and may not this occa- fion thofe gleams and llreams with which this phenomenon is ufually attended? N° vm. Theory of Water Spouts, by Andrew Oliver, EfquirC', of Salem in the State of MaJJachifetts. IN my laft I took the liberty to communicate to the Phi- lofophical Society a Theory of Lightening and Thunder Storms, which was iiiggefted to my mind upon the peru- fal of dodor Prieflefs hifiory of eledricity. In the in- veftigation of which theory, while I was endeavouring to account for the exhibitions of thofe phenomena upon the ocean, at great diftances from the land, fome thoughts na- turally occurred relative to the 110 ater f pout ; a phenome- non as curious perhaps as any one in nature, and which can rarely take place but at fca. Water. SPOUTS have by fome been fuppofed to be mere- ly eletSrical in their origin; particularly by Xx^mox Beccaria, (Priejileyh hift. of eled:. p. t,^^, 0,^6) who feems to have fupported his hypothefis by fome experiments. But as feveral fuccelfive phenomena are neceifary to conftitute a complete water fpout, (fome of which undoubtedly de- pend upon the eleftric principle) if we attend to the mod authentic defcriptions of thefe (pouts, through their vari- ous ftages, from their firft exhibition to their total diffipa- tion, we fnall be obliged to have recourfe to fome other principle, in order to obtain a complete folution. I fhall therefore, /r/?, defcribe thefe phenomena according to the beft obfervations 1 have met with ; and then^ endeavour to give 102 T H E O R Y OF give a general philofophical folution of them. But I muft here obferve, that the following defcriptions are all taken from the accounts of mariners, who are indeed the only perfons that have opportunities of viewing them; but, un- fortunately for the caufe of philofophy, do not ufually ob- ferve them with that circumftantial accuracy, refpefting the previous and fubfequent ftates of the atmofphere, which may be neceffary to found a complete phyfical folution upon ; nor with any view to that end, as it is foreign to their main bufmefs, trade and commerce. But as fuch ac- counts are the beft I have met with even in the Tranfac- tions of the Royal Society down to 1 744, lower than which I have not feen them; from fuch I fhall endeavour to draw the beft conclufion which the nature of the evidence will juftify. The moft intelligent and beautiful account of a water fpout that I ever met with, is in the abridgment of the Phil. Tranf. vol. viii, by Martin, pa. 655, as it was ob- ferved by Mr. Jofeph Harris, May 21, 173-2, about fun- fet, lat. 32"^ 30' N. long. 9° E. from cape Florida ; which I fhall here tranfcribe. " When firft we faw the fpout (fays he) it was whole " and entire, and much of the fhape and proportion of a *' fpeaking trumpet ; the fmall end being downwards, and " reaching to the fea, and the big end terminated in a black " thick cloud. The fpout itfelf was very black, and the " more fo the higher up. It feemed to be exactly perpen- " dicular to the horizon, and its fides perfectly fmooth, " without the leaft ruggednefs. Where it fell the fpray " of the fea rofe to a confiderable height, which made " fomewhat the appearance of a great fmoke. From the " firft time we faw it, it continued whole about a minute, " and till it was quite diflipated about three minutes. It " began to wafte from below, and fo gradually up, while " the upper part remained entire, without any vifible al- " teration, till at laft it ended in the black cloud above. " Upon WATER SPOUTS. 103 *' Upon which there feemed to fall a very heavy rain in " that neighbourhood. There was but little wind, and " the fky elfevvhere was pretty ferene " In other accounts contained in the Philofophical Tranf- adions, thefe phenomena are defcribed as having the ap- pearance of a fword pointing downwards, fometimes per- pendicularly fometimes obliquely towards a column of wa- ter or froth, which feems to rife out of the fea to meet it, attended with a violent ebullition or perturbation at the fur- face. Again in others the appearance is compared to fmoke afcending vifibly as through the funnel of a chimney, either diredly, or with a fpiral motion, which according to the fancies of fome refembles the afcent of water in the fcrew oi Archimedes ; by fuppofing fomething fimilar to which in the atmofphere, they have endeavoured to account for ■the rife of the water from the fea in a water-fpout. To which I would add, that, from the relations of fome pcr- fons who ufe the fea, with whom I have converfed upon the fubjed:, I find that it is no uncommon thing, during a calm below, and a ferene fky above, to obferve at the diftance of two or three leagues a fmall cloud hovering in the air, from whence the commencing fpout feems to dart downward to the fea, upon which the nfual phenomena take place in their order. I have alfo been informed (and to information I muft truft, having never been at fea) that it is common during thefe appearances for fliips to fail, even within hail of each other, with different winds; and within the limits of the fame vifible horizon, with contrary winds: And laftly, that the rife and progrefs of this pheno- menon is fometimes fo rapid, that, even in a ferene iky, a few minutes will be fufficient to generate a cloud from one of thefe fpouts, and to difcharge from thence a heavy fhow- er of rain. Before I proceed to attempt a philofophical folution of thefe curious produdlions of nature, in which the two principal fluids of our globe, air and water, are largely concerned j. 104 T H E O R Y OF concerned; it may be neceffary to make fome obfervatlons upon the nature and properties of fluids in general, as fuch. 1. No fluid can be at reft unlefs every part of it refpec- tively be a£ted upon by an equal force or preflure in every direction, till when its feveral parts will neceflarily recedtr from the greater preflure towards the lefler, nor can an equilibrium take place. 2. If two or more fluids of difi'erent natures and denfl- ties come together, fuch as quickfilver, water, oil and air, which will not mix; they will take their places according to their fpecific gravities, the denfeft remaining at the bottom. 3. If a veflcl be filled with either of thefe fluids, and a denfer be admitted into it, the latter will expel, and take place of the former. 4. If an empty cylindrical fpace be furrounded on all fides by a fluid, which is excluded by fome refifting fur- face terminating that fpace, the fluid will neceflarily, upon the fudden removal of the obftacle, immediately flow in from every fide towards the center of the void; and as it flows inwards the parts next furrounding this fpace will thereby be crowded together, and force each other up- wards, till at length when clofed, the fluid will by its af- cent have formed a column diredtly over the middle of the fpace, to a height proportionable to the united force of the converging currents. This muft be the cafe with every fluid thus flowing into a vacuum; and in a lefl'er degree when a denfer fluid in a fimilar fituation fupplants a rarer: And the greater the diff'erence of the denfities of the two fluids might be, the more confpicuous would be the effe&. This reafoning may be illuftrated, and the conclufions exemplified by fadts which muft have occurred to the obfervation of every one. Do we not obferve when a fliower of hail, or rain in large drops, falls upon the fur- face of ftagnant water, that the water rifes wherever they fall, like fo many little inverted icicles, which again inftantly WATER SPOUTS. 105 inftantly fubfide ? The caufe of which undoubtedly is, that thefe drops, or hail-ftones, defcending from a great height; in the atinofphere, acquire feverally fuch a momentum in their fall as to plunge through the furface to a proportional depth, driving the fuperficial water back on every fide, and leaving a momentary vacuum behind them ; not in- deed a pure vacuum, but fuch, relative to the furrounding fluid, which immediately returns to fill up the chafm, and, as it clofes, gathers and riles in the little columns above defcribed. When a large round ftone, or any other heavy body plunges, the effed is proportionably greater. 5. Let us, for argument's fake, fuppofe the atmofphere over any certain circular trail; of ocean of fome miles in diameter, to be for a moment annihilated, the fpace it oc- cupied before being reduced to a pure vacuum : The fur- rounding atmofphere, when at liberty, would rurti in from every quarter towards the centre, where the converging currents would immenfely croud each other, and force up a vaft quantity of air through a very narrow funnel, con- tradted below by the united preffure of thofe currents from all fides, into the higher regions ; which funnel, as the denfity of the air leifens according to its height, and the furrounding prefllire which contracts It muft decreafe near- ly in the fame proportion, would more and more diverge and expand the higher it rofe above the furface of the fea. This would be attended with a mol^ furious blafl of wind up to, and far above the top of the atmofphere. In like manner, 6. If inftead of a pure vacuum, or a total annihilation of fuch part of the atmofphere, we fuppofe the fame to be- come, by any means whatever, fpecifically lihgtcr than the furrounding regions, the cffeft would be the fame as above, in kind, though not in degree ; the denfer air flowing in, but with lefs rapidity, from all quarters without, expelling the lighter and fupplving its place, as in article four; upon which alio a large quantity of this confluent air, for the O fame loG T H E O R Y OF fame reafon, would be driven up with violence through a like narrow vent, yet not with the fame impetuofity, nor to the fame height as if forced through this funnel into a pure vacuum. That the atmofphere over large tra£ts of fea or land may thus become fpecifically lighter than that over the fur- rounding regions, will be evident, if we confider, i. That heat has a natural tendency to rarefy and expand the air upon which it a£ts. .2. That the atmofphere over our heads docs not confift of mere elementary air, but is an univer- fal receptacle of all the heterogeneous vapors and effluvia' that are perpetually exhaling from every fubftance that exifts upon the face of the earth, whether animal, veget- able or mineral. 3. That, by the cafual difpofition of thefe vapors and effluvia in the atmofphere, the air, which- is, of itfelf, naturally enough difpofed to acquire heat from the paflage of the fun's rays through it, may become more- difpofed to imbibe and retain that heat, in one region, than- in another in its neighbourhood ; which, from the inter- vention of clouds, or from its purity and freedom from thofe fleams and vapors with which the former is charged, may, in a great degree, retain its natural coolnefs and' denfity, while the other becomes heated, rarefied and ex- panded, and is thereby rendered fpecifically lighter. That thefe different affedlions of the atmofphere aclu- ally take place, and difpofe the air, at one time and in one place, even in the fame fcaions of the year, to imbibe and retain the heat excited by the fun's rays, more than at another, is not a matter of mere conjedlure ; but, what- ever the caufe may be, is notorious to all perfons of ob~ fervation. Thefe things being premifed, I beg leave to obferve fur- ther, that fome parts of the ocean are liable to long and extenfive calms, during the continuance of which the heat is fcarcely tolerable. Where thefe take place the air muft neceifarily undergo proportional changes in its denfity and ele£lric WATERSPOUTS. 107 dearie capacity* ; and when heated and rarefied to {hme certain degree will give way, as obfcrved above, to the denier air, now proportionably difpofed to flow in from all quarters without the limits of the calm. When once this ftagnated air, efpecially if of any great extent, becomes fpecifically lighter than the furrounding air, and fufficiently rare to be fupplanted by it ; the latter will, of courfe, fet it from every fide in horizontal currents; which will flow, either diredlly, or obliquely, towards one point, in or near the centre of the becalmed region afore- faid ; the obliquities of which currents will depend upon the diredions and velocities of the winds, or currents ot air which might previoufly have taken place in the fur- rounding regions. When thefe currents arrive at the cen- tre of their mutual convergency, all the ftagnated and ra- refied air which was before incumbent upon the calm fur- face of the fea, will have been expelled and forced higher up into thcatmofphere; upon which thefe currents, by their mutual concourfe in one place, will exceflively croud each other, as obferved above, wherever it happens, driving the central air upwards with a violent blaft ; which, fhould the currents fet in obliquely, and fo converge with a fpiral motion towards the centre of their mutual concourfe, would afcend as through the fcrew of Archimedes, or the ■worm of a cork-fcrew, to both of which navigators have likened thefe fpouts : Otherwife it would rife through a flrait, narrow funnel, as inarticles five and fix above; which if filled with any opaque matter would become vifible, and at a diftance would refemble a fpcaking trumpet with the fmall end downwards, in which form the water fpout fre- quently appears. In the former cafe a whirlwind round about the centre would undoubtedly be the confequence ; and in either, a water fpout would probably be producedf. O 2 For • See Theoi-y of Lightening, &c. page 8l. t We (hall in the fequel fee abuiulant reafon to conclude with doctor FranUm and others, that water fpouts at fea and whirlwinds on the land (fomc fpecici-of ihematleaft) are produc- ed by the fame caufcs. io8 T H E O R Y OF For the preflure of the atmofphere is taken off from that part of the furface of the fea, which is diredly under the funnel through which the air is driven up; whereas the furrounding furface is at the fame time uncommonly pref- fed, from the confluence of the currents from all quarters*, Avhereby the water muft necelfarily be forced up to a cer- tain height, proportional to the furrounding preflure, through the fame funnel with the air itfelf, nor is this all, for in their afcent the air and water become confufedly mixed together, whereby the latter is broken and attenu- ated into the finefl; globules and particles, as when one forcibly blows water out of his mouth; and from this mixture of the two fluids doubtlefs arifes that opacity which renders the fpout vifible. This opaque column of air and water, together with the paflTage through which it afcends, will expand as it rifes, in proportion as the comprclTure diminillies; and, to fpec- tators at too great a diftance to difcern the narrow flem next the water, will refemble a fword, or acute cone pointing downwards from a fmall cloud; to which they are frequently likened. But that they do at the fame time communicate with the fea is evident from the perturbati- on of the water directly under them, which fometimes boils and foams at a great rate. This is ulually the firft appearance of one of thefe fpouts, the duration of which is either longer or fhorter, and the fubfequent phenome- na more or lefs confiderable, according to the extent of the caufe, and the mode of its operation. The water being thus railed from the fea, and forced irrefiftably upwards in the fineft globules by the protrud- ing air, arrives at length at the warm electrical airf lately expelled, * In the abridnjmcnt of PhilofophicalTranfaflions, vol. IT. (by Eames and Martin) page 6 1, at the bottom » it appears, that the meeting ot" two contrary currciits of air or contrary winds, rai- fes the mercury in the barometer near tlie place where it happens, which indicates an incrcafe of the prefTiirc of the atmoi'phere upon the furface of tlie earth or fea. How much more then mud that prelfure be increafcd, from a general confluence of the air from all quarters towards one Ipot ? t Sec Theory of Lighteningj &c. page 90. j WATERSPOUTS. loc^ expelled, which was previoufly Incumbent upon the calm furface beneath ; the ele6lric attraction of which probably alhfts the further afcent of thefe particles after the iirft fury ' of the blaft is fpent. There it undergoes another opera- tion being converted into vapor, whereby it is wholly dif- charged of the marine falts it carried up with it*'; which are now left to fhift'for themfelves, together with innu- merable other heterogeneous corpufcles which fuceffively float in the atmofphere, and which in due time, become feverally fubfervient to many wife purpofes in the cecono- my of nature. Thefe vapors will then be greedily attach- ed by the craving particles of this air, now deficient of its natural quantity of eledlric matterf, and form a denfe cloud, in like manner as thunder clouds are formed over the land ; but with much greater expedition, as the fupply of vapors is more fudden. This cloud will then be ready in a Ihort time to difcharge a fhower of frelh water upon the fea from whence it rofe, and may be attended with thunder and lightening, or not, as the air in which the cloud was formed was more or lefs eleftrical, or the cloud extenhve. A previous calm may not be necejfary to the production, of thefe phenomena, and indeed they frequently happen without one: But, upon the fame principle, if it be calm- er where they arc produced, or the ftate of the atmofphere there be fuch as to difpofe it to acquire and retain the heat acquired from the fun's rays, more than in the furroimd- ing regions, which, as we have feen above, may be the cafe, the efFedts may be the fame in kind, though perhaps not in degree; the moft perfect water fpouts probably rif- ing from whence there has previoufly been a dead calm,, or nearly fuch, for the foregoing reafons. If *• The water carried up in one of thefe fpouts is undoubteiUy fait when it firft rifes from tlie fea, as it afcends in great cjuantities, and in a very denfe column; but it is always frefh when it defcends again in a fhower : It mull tlierefore in tlie mean time have gone through a compkat natural diftillation. f Theory of Lightening, &c. page 92. I no T H E O R Y OF If there be any wind at the time of the phenomenon, the aerial funnel through which the water afcends, inftead of being perpendicular to the horizon, as it would be in a calm, might incline more or lefs to it, in proportion to the ilrength or weaknefs of the prevailing current of air: Or, inftead of continuing in one fpot, it might have a progref- five motion over the furface of the fea, in the direction of the general current; both of which circumftances frequently take place. In either cafe it is natural to fuppofe, that both air and water would afcend fpirally, as through the worm of a fcrew, every current which fets in towards the centre receiving an oblique bias from the prevailing current. It fometimes happens, that after the fubfiding of a fpout, it is fucceeded by a fecond, and that by a third, either in the fame place, or at no great diftance from it. But this alfo is analogous to what we obferve upon the plunging of heavy bodies out of air into water. For, after the firft fubfiding of the fmall column of water which is occafion- ed by it, and is above refembled to an icicle, the water again rifes and fubfides as at firft, though not in the fame degree, as may be concluded from thofe fainter concentric circles which expand from the fame centre after the fub- fidence of the firft column. The fame thing which here takes place in water, may alfo take place in air, under fimilar circumftances. Since writing the foregoing, while I was endeavouring to contrive fome experiment to illuftrate the fubjedl, a very fimple one was fuggefted to my mind, the fuccefs of which I think demonftratcs the truth of the hypothefis introduced above to account for the firft afcent of the water in the fpout ; the event being precifely the fame as was expected before hand, and as ought to have taken place upon the principles above advanced. EXPERIMENT. In a ftifF paper card I made a hole juft big enough to infert a goofe quill fo as that it might be fixed perpendi- cularly WATERSPOUTS. xir cularly to the plane of the card : After cutting the quill off fquare at both ends and fixing it, I laid the card upon the mouth of a wine glafs, filled with water to within one fifth or fixth part of an inch from the lower orifice of the quill ; then applying my mouth to the upper part, I drew out the air in the quill by a ftrong fudtion, and in one draught of my breath drew in about a fpoonful of the wa- ter ; this by ftronger fu«5tions I was able to repeat again and again, the quill remaining as before. The water, as I expected, did not al'cend to the mouth in a ftream, as it would have done had the quill reached below the furface j but broken and confufedly mixed with the air which afcend- ed with it ; as is above fuppofed to be the cafe m the afcent of water in a fpout at fea. In this experiment the fuftlon occafioned a vacuum, or at leaft a great rarefaction of the air, within and diredlly under the quill ; the furrounding air of courfe flowed in from every quarter to fupply it, rufhing up into the quill, and through it to the mouth ; the preffure of the atmof- phere being thereby taken off from the lurface of the wha- ler immediately under the orifice, while the prefigure upon the furrounding furface remained, and was probably in- creafed, the water was forced up together with the air as above notwithftanding the quill had no manner of com- munication with the water. If the fuftion be made very fi:rong, and the quill be fixed at the diilance of a quarter of an inch or more from the water, a confiderable agitation and ebullition takes place In the v/ater under it, fimilar to' that obferved in moft natural water fpouts, and the pafTage of the water from the furface to the quill becomes very vifible. It was hinted in a preceding note, that water fpouts at fea and whirlwinds at land, fome fpecies of them at leaf!:, arife from the fame caufe, how different foever their ap- parent effe(£ls may be. This I think is made fufficiently evident from the obfervations of a couple of land fpouts at Hatfield 112 THEORY OF Hatjieldm Torkpnrc, by Mr. Abr. de la Pryme^^ whofe ac- counts of them I fhall here tranfcribe, as the Tranl'adions of the Royal Society are in the hands of but few among us, and as the fa£ls related by him tend ftrongly to con- firm the prefent theory, however his conclufions from them may differ from it. " On the 15th of Auguft, 1687, (fays he) appeared a *' fpout in the air at Hatfield in Yorkjld'ire ; it was about a " mile off coming direiitly to the place where I was ; I *' took my profpedlive glaffes to obferve it as well as I *' could. " The feafon was very dry, the weather extret7ie hot, *' and the air very cloudy ; the wind aloft, and pretty " ftrong, and (which is remarkable) blowing out of feve- *' ral quarters at the fame time, and filling the air here- *' abouts with mighty thick and black clouds, layer upon " layer ; the wind thus blowing foon created a great twr- *' tex, gyration and ivbirUng among the clouds ; the cen- *■'■ tre of which every now and then dropt down in the *' fhape of a thick, long, black pipe, commonly called a *' fpout ; in which I could dillinftly view a motion like " that of a icrew, continually drawing upwards, and fcrew- *' ing up (as it were) whatever it touched. In its progrefs *' it moved llowly over a hedge-row and grove of young *' trees which it made to bend like hazle wands, in a clr- *' cular motion ; then going forw^ard to a great barn it *' twitched off in a minute all the thatch, and filled the " whole air therewith. Coming to a very great oak tree, *' it made it bend like the foregoing trees, and broke off *' one of the greateft and ftrongeft branches that would *' not yield to its fury, and twilling it about, flung it to a *' very confiderable diftance off; then coming to the place *' where I ftood, within three hundred yards of me, I be- *' held this odd phenomenon, and found that it proceeded *' from nothing but a gyration of the clouds by contrary •winds * Abridgment of Philofuphical Tranfadions, vol. IV. by Jones, page Io6, 107. WATERSPOUTS. 115 *' iv'inds meeting in a point or centre ; and where the great- " eft condenfation and gravitation was, falHng down into " a pipe or great tube (fomething like the cochlea Arcbi- " viedis) and that in ilvS working or whirhng motion, ei- " thcr lucks up water, or deftroys ihips, &c. Having tra- " veiled about a quarter of a mile farther, it dilfolved by *' the prevalency of the wind that came out of the ealt." The account of the other is as follows, viz. " I have *' feen another fpout in the fame place, which very much *' confirms nie in my notion of the origin and nature of " them. — The 21ft of June, 1702, v^diS, pretty ivarm ; on " the afternoon of which day, about two of the clock, no *' isjind Jlirring heloiv though it was lomewhat great in the *' air, the clouds began to be mightily agitated and driven *' together ; whereupon they became very black, and were " (moft vifibly) hurried rounds from whence proceeded a *' moil audible whirling noife, like that commonly heard *' in a mill. After a while, a long tube or fpout came *' down from the centre of the congregated clouds, in *' which was a {w'lhfpiral motion like that of a fcrew, or *' the cochlea Archimedis when it is in m.otion, by which *' fpiral nature and fwift turning, water afcends up into " the one as well as into the other. It travelled flowly " from weft to north-eaft, broke down a great oak tree or " two, frighted fome out of the fields, and made otheii " lie down flat upon their bellies, to fave being whirled *' about and killed by it, as they faw many jackdav>?s to *' be, that were fuddenly caught up, carried out of fight, *' and then caft a great way amongft the corn ; at laft it " palTed over the town of Hatfield^ to the great terror of " the inhabitants, filling the whole air with the thatch that *' it plucked off from fome of the houles ; then touching *' upon a corner of the church, it tore up feveral fheets of *' lead, and rolled them ftrangely together ; foon after " which it dilfolved and vanilhed without doing any fur- " ther mifchief. P " 13y 114 T H E O R Y or " By all the obfervatloas that I could make of this, and " the former, I found that had they been at fea and joined " to the furface thereof, they would have carried a vaft " quantity of water up into the clouds, and the tubes would " then have become much more ftrong and opaque than *' they were, and have continued much longer. " It is commonly faid that at fea the water colledls and " bubbles up a foot or two high under thefe fpouts before *' that they be joined : But the miftake lies in the pellu- " cidity and finenefs of thofe pipes, which do moft certain- " ly touch the furface of the fea before that any confider- " able motion be made in it, and that, when the pipe be- " gins to fill with water, it then becomes opaque and " vifible." I fhall here make a remark or two upon the above cited author's mode of expreflion in the foregoing accounts, which is evidently adapted to a preconceived idea of the cochlea Arcbhnedisy by fuppofing fomething limilar to which, as taking place in our atmofphere, he is not alone in endeavouring to account for thefe phenomena. In con- formity to this idea he fpeaks of the fpout ;:$ draiving up- tvards-, and Jcreiving up whatever it touched ; and fup- pofes that by its fpiral motion and fti'ift turning, water afcends in it as in the Jcreiv of Archimedes. But this hy- pothefis, however fpecious, has been long fmce exploded as unphilofophical. Mr. de la Pryme mentions the appearance of a long black pipe which now and then dropped down from the centre of the gyrating clouds ; in which pipe he diftindlly view- ed a motion like that of a fcrew ; and as fuch he leems to have fuppofed it ailed, viz. either in the manner of a cork- fcrew upon folids; or as the cochlea Archimedis upon fluids, drawing them up into the atmofphere. But as he himfelf afterwards, when applying his obfervations to a fpout at fea, very juftly concludes that the pellucidity and finenefs of thefe pipes over the water render them invifible below, " uotwithftanding WATER SPOUTS. 115 " notwithftanding (as he conceives) that the pipes do moft " certainly touch the furface of the lea before any confider- " able motion be made in it, and that they are then rendered " opaque and vifible when they begin to fill with water ;" might he not with equal reafon have fuppofed that thofe aerial pipes which he obferved over the land were alfo con- tinued from the clouds down to the furface of the earth, as from their effedls below, one would naturally conclude they were, and that they were pellucid and invifible fo long as they contained nothing but air ; but that " every " now and then," when they met with any fiibftances which might perchance pafs within the compafs of their gyration, or which they could eafily carry up ; fuch as detached parts of the broken clouds ; water from ftagnant ponds, brooks and rivers, hay, ftubble, thatch, diift, &c. they then become opaque and vifible, and that they ap- peared to dart downwards by a kind of optical deception ? For upon the foregoing principles thefe pipes of air muft neceffarily be broadeft above, as we have already feen, and terminate in a narrow ftem below, the broadeft part being, at a diftance, firft vifible, and the fhank feemingly taper- ing downwards to a point. It is however certain from the eftefts of the above mentioned fpouts, that, whatever the appearances were aloft^ they were all occafioned by the rufhing of the air upwards through a narrow paffage, that was contradled bdov)^ by the concourfe and predure of the oppofite currents of that fluid, and dilated above from the diminution of that preiTure. I have referved for this place an account of a curious fpout which made its appearance anno 1694, not at fea, but in the harbour of TopJJ.mm'''^ , and at low M'ater ; which palled with a flow progrefllve motion over both land and water; aifting as a complete water fpout over the latter, and as a whirhvind upon the former: For when it pafl'ed over the channel of the river, it threw up the water in a denfe P 2 ftream, • * Lowthoqj's Abiidgm. Pl'.il. Tranf. vol. II. page I04. ii6 THEORYoF ftream, as If It had been impelled through the hofe of a fire engine, and the ftream accordingly ended in a thick mift, refembling a dark fmoke; the furface of the water, round about the fpot from whence it rofe, being greatly- agitated, as is ufual in thofe phenomena. In its courfe it rnet with the hull of a new fliip of about one hundred tons, which was much fliaken by it, but received no hurt. In paffmg over the flats it took hold of a boat which was fallened to an anchor, whirled both boat and anchor to fome heicht in the air, and rent the boat " from the head " to the keel.'''' When it reached the fhore it lifted up an- other boat about fix feet from the ground, letting it fall again upfidcdown; and had a ftrange effe£t upon a parcel of planks, fome of which were raifed up perpendicularly, and flood upon their ends while it paffed along; and in its further progrefs it was attended with the ufual effects of a whirlwind, fuch as ftripping off, not only thatch, but fheets of lead from the tops of houfes, and tearing off the limbs of trees. This account may tend to confirm the theory here offered, as it proves to a demonftration, that the water fpout therein dcfcribed, was occafioned by a pre- vious whirlwind in the atmofphere ; which whirKvind was aUo occafioned by the rufliing of a large quantity of air, upwards, from all quarters near the furface of the earth,, through a very contraflied aerial paffage, towards the top of the atmofphere; the narrownefs of which paffage, as determinable from the effeds obferved in its progrefs, iliews it to have been compreffed upon all fides by a general con- flux of oppofite currents of air ; as the rufliing of the air through it with fuch violence from beneath, does, that the denfity of the fluid and the compreffive force of the cur- rents were greateft there. The afcending air carried up the water with it through the fame paffige ; not by any mechanical operation upon it, like theadtionof a fcrewof any kind ; but, m.erely, by taking off the preffure of the atmofphere from the furface of the water dircdly under it; WATER SPOUTS. 117 It; •u'hence the water mufl: neceflarily afcend, as in any common hydraulic machine; and that with a force pro- portional to the prefTure of the atmofphere upon the fur- rounding furface, now greatly increafed by the confluence of thofe currents. Before I clofe this fubjeifl, I fhall juft mention, withont making any remarks, the efFedls which a whirlwind had amongd a number of fliocks of corn at IVarrington in NoythmnptonJIjire^ Auguft ift, 1694; out of which from eighty to a hundred Ihocks were carried up into the air, a great part of them out of fight; thefe when the fury of the blaft was fpent, fell down again at the diftance of fomc miles from their own field. The account of this whirl- wind immediately precedes the article laft quoted from the P hilofophical Tranfaftions . Should the foregoing theory be adjudged tenable, it will render very credible thofe ftrange accounts which we have fometimes had, of its raining tad- poles and frogs, which have been found upon the tops of houfes after a fliower; and even fmall fifhes, a fhower of which fell at Cranjlead near Wrotbmn in Kent, anno 1696, on the Wednefday before Eafter (Lowtborp's abridgement of Philofophical Tranfidions, vol. II. page 144.) For fhould one of thofe aerial pipes pafs over a frog pond, or the fliallow parts of a fifh pond, the fame natural caufe which in a fpout at fea, would carry up the water from the ocean, would alfo carry up the water from the ponds ciforefaid, together with the contents; whether tadpoles, frogs or fifhes: Thefe mull defcend again fomewhere; and where- ever they fell, a fhower of filhes, frogs or tadpoles, would be the confequence. J^xperimeyits. [ ii8 ] N° IX. Experiments on Evaporation., and Meteorological Obferva- tions made at Bradford in Neiv-Englatid, in 1772, by the Rev. Samuel Williams, A. M. IN making experiments on the quantity of water that evaporated in the year 1771, the method I ufed, was to fill the veflel the beginning of every month: In the courfe of thefe experiments, I obferved that in the begin- ning of the month when the tube was newly filled, it ex- haufted much fafter than towards the latter end, when one or two inches of the water was evaporated ; and that the quantity of evaporation meafured this way, came out lei's than the quantity of rain that fell in the courfe of the year. The beginning of the year 1772, I attempted to examine this matter more carefully. With this view I made the following experiments. EXPERIMENT I. I procured two cylindrical vefiels of three inches diame- ter, and fix deep, as much alike as they could be made: One, I filled with water as I had done in 1771, once a month ; the other, with the fame kind of water, once a week; and placed them about fix inches apart, in fuch a manner as to be expofed to the wind, and fun, but cover- ed from the rain. The refult was, that which was filled once a week, exhaufted about one third more than the other. In January and February, the difl"erence was a little lefs; in March and April, it was a little more, in May, the lafl: month in which I compared them, the evaporation from the former was 6.35 inches ; from the other 4. 1 o. By this experiment EXPERIMENTS on EVAPORATION. 119 experiment I was convinced that it never could be known with much accuracy by either of thefe methods, what quantity of water does really evaporate from the furfacc of feas, lakes and rivers. For in the one cafe, after about an inch is exhaufled the furface of the water is too much flieltered from the wind, which greatly retards the evaporation. In the other, as the water has all the advan- tage of the wind, and is heated by the fun, and atmol- phere, to a confiderable greater degree than the water in feas, lakes and rivers, the quantity of evaporation comes out too much. And therefore nothing certain as to the real quantity of evaporation from watery fluids, can be de- termined by fuch experiments, however carefully they may be made. EXPERIMENT II. To meafure with more certainty the real quantity of evaporation, I attempted in the next place to examine what it was in facl from the furface of a river. This ex- periment was made in the following manner : I filled one of the veffels with river water, and placed it as before. The other I fixed in the centre of a circular board of three feet diameter. This inftrument, by means of a line faftened to a tree on a fmall ifland, was placed fo as to float near the middle of Menimack river. To defend the tube againft the dews and rain, a circular piece of glafs, fifteen inches diameter, was fupported by wires fixed to the board, eight inches above the tube; and the whole was i'o balanced by weights as to leave half an inch of the tube above the furface of the water. When thus afloat I filled the tube with water, propofing to let it remain in this fituation a week, to fee how much would evaporate in that fpace of time. After repeated difippointments by the rain, wind and waves, for three months, I at lad fuc- ceeded in trying the experiment from Aiigufi 26th, to September 2d. During that time there was little wind, mil I20 exper!ments on evaporation. ftill water, no rain, nor any thing to difturb the experi- ment. The event was, that at the end of the feventh day, the tube was exhaurted 1.15 inch. And that no water had got into the tube in that time, I was certain from this circumftance ; all that part of the furface of the board which was within half a foot of the tube was dry every morning and evening. In the other tube, the evaporation in the fame time was 1.50 inch; which gives ^^ decimal parts of an inch difference between the real evaporation from the furface of the river, and that of the water v/hen fui'pended in the air, as in the other vefl'el. All the eva- porations therefore meafured the latter of thefe ways, ought to be diminifhed in this proportion, to have the true quantity fuch as it is in nature. EXPERIMENT III. Thefe experiments on watery fluids put me upon en- quiring what the evaporation was from the furface of the earth. To determine this, Sept. 14, two days after there had been any rain, I funk one of the veifels into the earth in a light foil, fo as to take up all the earth contained in a fpace equal to the contents of the veflel. Elaving care- fully weighed the veflel with the earth it contained, I fix- ed it in the ground in a plain open field, where it was ex- pofed to the fun and wind, but defended from the dew and rain, as in the former experiment. At the end ofj'e'uen Jays I took it up, and weighing it again found it had loft 783 grains, troy. The diameter of the veflel being three inches, its furface exprefl^ed in whole numbers was equal to nine fquare inches. Dividing the number of grains that evaporated, 783, by the number of fquare inches contain- ed in the furface of the veflTel, 9, we fhall have 87 grains for the evaporation from one fquare inch ; and this, (af- fumlng 254 grains as the weight of a cubic inch of water) will give -j-Vtt parts of an inch, as the depth of water that paflTed ofi^ by evaporation. In the other vellel filled with water, EXPERIMENTS on EVAPORATION. 121 water, and placed as before, the evaporation in the fame time was exadly one inch. If this experiment may be fuppofed to reprefent the operations of nature, the con- clulion will be, that the evaporation from the furface of the earth, is but little more than one third of what the evaporation is from the furface of water. EXPERIMENT IV. Another thing I had in view was to know what the eva- poration was from plants and trees. In order to make an eftimate of this, Augujl 20, I took up four different forts of plants, with as much of the earth adjoining to each as wholly covered their roots. Each plant, with the earth thus about it, being fix inches fquare, I put into a wooden box of the fame form and fize. The boxes were covered with thin lead, well cemented at the joints, that nothing might evaporate that way ; and had two apertures at the top ; one, to admit the ftem of the plant, the other, that the plant might be fupplied with water, but which was kept flopped when not in ufe. Having taken the weight of each, I placed them in the ground that they might have the fame degree of heat as before ; leaving as much of the plant above the furface of the earth, as when it was in its natural ftate. In this fituation I added known quantities of water, aiming to put in from time to time as much as I thought they would throw off. At the end of thirty days I took them up, taking an account of their weight as before, and alio that of each plant. The refult is expref- fed in the following particulars ; w. federal forts Weight of the Water evaporat- of plants. plants. ed in 30 days. Gmins. C. rains. Apple tree, - - - 23 - - - - I27I Alder tree. - - 30 - - - - 2593 Spear mint, - - - 22 - - - - 5186 Clover, - - - 43 - - - - IS94 Q. In 122 METEOROLOGICAL OBSERVATIONS. In this experiment, the evaporation from thefe four very Tmall plants was 10944 grains; amounting to about 43 cubic inches of water, in thirty days. The evaporation in the fame time from the veffel fufpended in the air, was 4.25 inches in depth : The quantity therefore thrown off by the plants, was more than what the evaporation would have been from a watery furface, of ten inches fquare. If this way of reafoning may be applied to fields covered with trees, grafs, and other vegetables, the inference will be, that the evaporation for feveral months is greater from them, than it is from equal areas of the furface of water. METEOROLOGICAL OBSERVATIONS made at Bradford in 1772. THE inftruments ufed in the following obfervations, the times at which they were taken, and the method in which they are fet dovs^n, were defcribed in the paper fent to the Society lafl: year. With regard to thofe of the pre- fent year the following things are to be obferved : The barometrical obfervations till Nov. 6, muft be viewed as imperfc£l, being taken with a barometer of too fmall a bore. From the 6th of November to the end of the year, they are very exa£t ; being taken by a very good barome- ter made by Nairne. In meafuring the quantity of eva- poration, I ufed a tube three inches diameter and fix deep ; which was filled once a week. The rain was meafured by a tube of the fame form and fize. In all other refpeds, the fame method was obferved as in the meteorological obfervations of 1771. The obfervations taken by the barometer and thertnome" ter are fet down in three colunins ; the firft column con- tains the obfervations taken ufually about 6" A. M. the fecond at noon, and the third at c)*" p. M. The other co- lumns give the general ftate of the wuids and weather of the day, J A N U- METEOROLOGICAL OBSERVATIONS. 123 V- -t-J C< M M ^ .5 . S 5 C J2 > t^ ght. night. 11 the eve • night, t intcrva bright c rvals. ow in th' y ^ << r day ; fnow in e pleafant weath udy day ; rain i e pleafant weath ar bright day. to. Aurora lior, udy, dull weath e pleafant day. to. to. to. udy day ; fnow ing clouds with Id pleafant day. to. iw A. M. clear ar bright day. ■udy, with fome ludy dull weathe rm of fnow, all r weather. ludy dull day. ■udy, with brigh 11 milling day. e pleafant day. to. udy dull weathc to, with rain. r and clear. udy day ; ftorm udy dull weathe N t~^ oj t^ '' ^-1 — ba . ,^. -u ^ . s . ^ . ^ ^'^^ . .'S^- "^ '. to S. '. httle . W. ft ^ to s. '. little itto. itto. itto. , frefh. W. to ^ little itto. E. to . to S. . toN. . W. E. little, itto. '. little itto. '. little, . E. frc . E. to ^ ??u-;c/:■2;z??aoawc/:■?QM?zzzzv^•^/::as:zzq?2;^; < Hit* Mf'Mif* M|c* Miei m|hw;h m;hm!h vo O ^". *-< oo O c* ex ^>0 -O f* ^ O >^;O0 O 00 r^ O C^&^ O O O M o r^so "^ ^ P S c*^'". '^'". ^Mt^c H'* >0 r^ "1 O •* ^oOO 0'-<0»^f^O^'^»^^-+»-''000^'tC>. •^NO rt >H C c^ 1^ £ rtt^w-i-r^dM^^lf^, ^'^rtrt^dC^^clMrtc^MWW-, c^. «--c«»-tMc^r^*--, < H— , Mlc< M^C» Ht* ^T* Mlrl-lt* «|H Mlc» M t^CSO r^NO r^. ^ r^ t^Oa i-i %0 »^00 "". r*-, ^h O&O t^MOOOO »^00 ^. O t^xO O ^C ►Hc-i M .J r^.co o >H t- w M o 'i-^ OONOO'^ir^MsortwOO 'n^O »^ M t^.sc C C CN:>.^d"cro'^G'crc)c>sDvOs^:N;>.:^ ^03~ c>.o.c^C\:>C\Cvo^dvc^^'oc' e'. '^rtrtrtt'^f^t^, t^r^c«^(c*c^«c^^tc»c^c^c^c^c^c^c^c^^^^tc^c; M|f> w:c*MtcJ Mjrt "l<-^KMO0.-M00 ^^ i^ c^ '■': r-~ o o^crc>^CNCNO"o O O O c^asOv:^!>.ON:>. c>oo cx^dsc>oid^dv^ o^oo' c< rorrirtwrtcir^, r-^r^r^. r^j c^c^c^c^c^c^c^c^c^c^cc t^oo ?*'!*■«'; wOCscJOC *^^o i^ c» r^. O f" doo^OsC^c^Ocrd"oocxc>.<>.osc?idsCN^ cxoo cx(>.(>.!:^dsc>.c^^ c>cc POc^«rt«rte*^w5«''-«^e^rtc. M c» c^ ^ u-jvO r-.00 O O w r» "^ ^ v^.sc I^OD O. O M ^ f , <*■ »^^ i^oc O O •-. ri »- M rt H P-* H^ i-i w M M ci c* rt r* r^ t» cs ^ c< t* f-. f-. 5^a^ I o F E B R U- 124 METEOROLOGICAL OBSERVATIONS. < pq Ph 1- QJ a Fair A. M; cloudy P. M. Fine bright day. Clo. day ; hea. ftor. of fn. & hail in the nig. Dull cloudy day. Flying clouds, with bright intervals. Fine bright day. Aiir. Bor> in the night. Fine pleafant weather. Cloudy dull day. Rainy A. M; cloudy P. M. bright even. Fair and clear. Ditto. Fair day. Fair day; cloudy evening. Snow A. M; clear P. M. Clo. A. M ; fn. with ra. P. M. & in thenig. Fair pleafant day. Flying clouds, with bright intervals. Fine pleafant day. Ditto. Cloudy day; rain in the night. Fine pleafant day. Ditto. Ditto. Ditto. Heavy ftorm of fnow and rain all day. Flying clouds, with bright intervals. Fine pleafant day. Aiir, Bor, in the nig. Ditto. Ditto. S. W. little. E. freih. S. to N. W. frelh. N. W. frelh. N. Wi little. S. W. to W. N. toE. S.E. S. to W. frefli. N. W. frefli. S. W- to W. frefh. N. W. N. W. toN. E. N. to W. W. to E. S. W. little. W. to S. W. frelh. S. W. little. S. W. Ditto. W. S. W. Ditto, frefh. W. S. W. to E. N. E. to S. ftrong. W. to N. ftrong. W. S. W. httle. Ditto, frefli. 1^ 1 O a ^^cl coc^ M coc*^c*>rt COM w w c<)rt «s co^»t^^^cot*jc* cO'i'cO MlHMc* Mirt M|c» M^^ Mr) M|e» C'Jf*^C^ CO CI C? eort <^« COM M M M cOc< cOCO»t>0^«J-^cocOCOCOco HC*H)C* MlHHC* Wlc< MIC*HIC»W|C* M ^O^a M '^■cocot^cl »oO COM l^ r^-O »o^O O Os^t'TOO "^M *oM r^ cOc^rMlc» M|C*Mlr^ MJHH1C»M|C* MN30 ^OvM^q^O r» O t^co.^Osr* MNO^ONONO'O *000 OO ^ M CO n CO OsCNCNOM>0 O O C?vO OCJ^o'oio^CNCKdicNC^C^CNCN C>Oc" !> OS ^ C>s c^c^c^c^c^cococo«coc^cococ^e^^C^^O^^C\ f^Oo" Cs 0\ Os c*c*c^c^c^•:oc^co^»c^c^coco^Mcoc^Me^«c*c^c^c^c^c^c^e^c^c* O coc^ Om^m o c< ^t^C)^rt 'trt M c*>o^*o*o c» .o"^ oo "O-O CO CO c^ :^ ^ CNoo !^ ^ CN c*c-| C* W Ht « C* toe*". COf^t^^^f^'^'O^fO^- J3 cu ^0^ rt CO ■* ^.vD tr^OO Ovf R APRIL, 126 METEOROLOGICAL OBSERVATIONS. < ^ I" 3 ;ItSs n G C rt fc.y M«^ S * S — t- C ^S ,■ t; .. 3 ■- I rt -S->^ . >r--S. _ = tj i: :; s - -2 .S ■- ■- — S ' c 'S c « ■= S . i-^ i_; " -g ^S1?S it o « 2 o" .« .ti _ii o c-^--^ !>^ c rt ■;;5 .ti "iq O':^ c;~ 3.^ c .— ."■: . vi: g P m ij .S .. w ftJ "_ P5 ? 'E ^ ■°. 2 W X Z ^ Z ^ W 'X W 12; 2i yi :/^ l> 1/) ^ y5 c/: k-.' ■ W . '"^ re . - .-;:; iW - - O C^ t5 Mir* m(^ H|r>-|c» i-i|r» • '-.SO CN I'-j »^00 00 00 M -ysO i-- t~-00 POO •000 *^CK^O 'I'O 00 t^00^£300 Ot-^r* )l~-clronl-^OsMr«0^0»^MOlH■*00 M|c» Hf' Mirt Mln C^.OO 03 ^ roOO CSOO ^ -t O O -^ ^o' 1 fOOO »oDO O r» SO •* M '^NO vO ^t(^(S(>cSOsC?\C>vOiC>OsOsCNC5 c5^0sCTstrs;>vO.CN(^^C^\CNCTv M c^ r<^ Tj- i>-,so r-oc cs O MAY, METEOROLOGICAL OBSERVATIONS. i2j < -j=: b/j . t; -Si 3S >^ c :=: ^ >- 1 ^ ^- -S 3 rt ^ <; <-< :^ s u. d o o o -= ~q q ^ '^ r"* '"^ p^Q^O|q■^p'w»ri. Sa .- c3 *J *J *J *j 0-— ri !^ b4 ^ >' ^ ;* o > q d 6 tti > :£ >* 1 "^ c/iPZWc/5>wZj3'Z^>PQcn&t>WZ'jiZt^O;n^3oZMZto'j;2 SS 2^ c .^ .3 o l^.i 6.2 r-^ r- to --"J '^ "^ "^ '^J ") 1- "^O ^ "^"O ^0 'O ^ "^J ^. '^'O t^^ ^ so -o »n •- t^ (-i>r-,o-)^'«f«^»o»o»0'o*^*o i^-o ^O so > .5 TS "o CU Jo <-§^ 2 — -ti ^ ■£"3 S; g o c o o o o <^£ U 4- *- , ^ =! 3 C 2 ^ '.ti o P •= .ti .ii 9. i" be - "9 c - *^ *^ *^ - - ■? '^ c .t; .ti .^ ^ ^ « -t: .t; ^ ^ >>.t: .t; _2 ^ c .t; . J O E O 'a 'A. (5 QQiioEQPQOUBiQQOOEQPoESQl t2 w w£ ;?; p g (5 2 z 2 3 3 z iz ? c/-: Q T -^ ^>0 'O'O "O t^sO NO »o ^ *0^ "O C-. ^ so >o ^ ^o »o^o so r^ i^^ r^ r>* r^ «^ O Cs ^ c^OO iSM rtc*00 Tj-r-^t-^n .\0 HO^WMSOrt'^ c-^sO tn'O r-* r^ r^ r^^o >s vi-^no ^o t-^oo r-^-o ^ -o ■>o so 'o'O r^ c-^so *^ t~»oo oo HlH MlH hIH M|f* Me* HlH Hf*'-'|r* H|rt •o so »o »^ ^nO so '^ »o *^ "^ "o >o^ r^so ,*o so *^ •*! 'O *^ *nso *o ■o ^ t-^so l^ . ■ T- < V ■ ■- — - ■ — - I CN(sIc?sc5'o'^'>CNCNC>.C>.OsC>.CsCnCnOsC>CNCnC>.C\C>.CvCN^ C^CtCl'-^rr;c»C^C*r*C-'|c*-1-'« >»'H mI'v-h|c» . HlrtHt* MCr r^ O *H O so »ooa 00 r-* ^"^ sons ^r>^2^'*'^^'^^^^'^^*^'^'^ oooo CsCNCNO O O C\OsCnC\OsCSC\CvCSOsCNCNC\CsCsOsCNCNC^:^<>.^:^Cs ^& JULY, METEOROLOGICAL OBSERVATIONS. 129 !^ (^' ; -5 ^ .3 g = .s 2-S g rS CJ P Q ; ■a .,,• ^ c . a So: 'S B a U O -rt ■ U 'J f^ 1^ c £ -J^^ S ; g 5-5 '- 60 S-1 1 t-" ,rt . • 3 3 ■- 3 .5 -5 .5 's -S— ° '5 S5- i =-a o o£ouu;feii;;2oSoa.[2i55Si2r. :3 ^ 2^^ ^ .^ ^ ^ .- ^ > ^ .• .^ .S .5 ^ ^ .^ -^ .^ .^ .5 -S .S -^ ^ .• ^ ° .^ .^".S ^ r-- t-- r^ r>oo 00 t-.oo 00 r>. r^ c^ c^ r^ r-*oo c^ 1^00 r> *^ t-^ r^, t-*oo 00 00 0\ Ovoo t^ ^ ^ i^n c^ >o ^o ^"-1 ■^^ O O CT^ Os'O >0 'O ^ OS w 0\ r^^ -o O t-^«o ^ PO f^ t^ OsOsO\0\OnC?\CTvOsCNO O O 0\O\0nCN3sOs0\0 ^OvO\dsc5'c^i^^CN ^OO* c4 iA bo J to C^NO I- 5 ^H 2 s> 6^5^ = H|ciM|r» M|-+ hW m|c< M|HM|rt Hr* M|f*H|HHf* •f ^ rj- -^xO ^ 00 fcn'O NC M CV OsO SO mD 00 O i-. M Q •^'O OO O 00 OO i<-) TfOO Q M c^ d Tf *osO r-00 OS O •-« rt "^ 'J- v^«g3 r^oO Os « rt r^ -* »^0 r-^OO O O t- AUGUST, I30 METEOROLOGICAL OBSERVATIONS. O < ^ bo ^^ 6^* u S ■= . &•■= £ a- • , c " '- o •- *^ ■- " ^ ^'<^-"-"'ri ^-2 = - ■- - ■- 'rt ^ S >:• ^ -^ ■" •" -^ i o o o ^ .2 , . .3^3 . . . .Z3 w2£o-S .^gW o o o ►J _,. .„„„ -■ ti.Jit:? ^* z CO 5 Q > 2; > :fi (5 Q c/^ 2 5 5 c/5 > ^ c/D S 2; w c/^ S ^ S 3 «■ - r-^ so 'O'O \0 so r^ r>.\o nO r-- r-^ r-\^ \^ t-^ r-^ !>. r^ r^cxj oo oo~^t^>o oo t^oo oo oo r^so so no -o «^ r^oo soso r^»>.r^i^r^(^ t-jvO »^ ^ (^ w »^nO oo i^r^rlO "^^O »oO Or^ ""Ort t^sO 00 ^ ti f^ r^ r^ rf >0^»OsO*0 r-.r-.r~ t-..>o sO »0 r^ r^ i^ r..\o <3 »^nO "O "O nO "O »o*0 t^ (^so '«0 sc m so rt rt so <^ "^ t^so so 1^ M- ij-i c* »o i^so »-.>o o *o f* O -^so d CO o n sc Os O" O" O" CN CN CX C^ CN CNOcToo" C?\C>CNdsCNCNC?sCKO"cN<:>. o'oo'oo' t>Oo" o' €5" Cs p* 1^ O 'O o Q W r* n ^ "^.SO r^oo O OS w IH IH M .--.SO M M S'g C-1 •^.so C4 c< Cs O M C* r^ rr. SEP METEOROLOGICAL OBSERVATIONS. 131 CO .S Oh « .-a ^ a. „ tS u Oi £ Q Q l2 ^3 '5 :'s c.ti.t;-;5 ri -g .s .^ .t: .^ UUp0 »■ <^"0 ^O ^0 r^ »^ «-, 'O '^.SS ^ i^.sO ^O *0 *0 ^O i^,s2 "o vrj t^^vo -O « Mlf* w)c> Hc^ H** Mr* i-inwl'^ ^ CNOO M O w t-. Tj- ro t-^NO M 00 00 O r-v t-v i^vo ^ r^, c^ rtOO M rt CN t^ O ^ t-^-O ^0 OQ r-NQ -O O I-- »o *^ '^ "^"O ^O »0 "--l^O NO ^O SO >0 -O "TiO »^ »OVD 'O " n 0" CN C> 0. 0. 0" CN <>. C>C^CNCNCXCNrN<^^CN ^ Cl tl W to rn •^ « c*i d M n r» c* rt c< rt CN Os CN C?\ OS Cs OS OS rs OsCNOsCNOsOCsOsOs — M C* M (S "^ <^ <^ r* rl C< d c* ct c» <» C< Cl c* C^ r* r< r< n M|<^M|rt t-[H HH HirtriH •0 r-- r» i-^ w Ht "^ 00 t *t •^^ CO 0^ 0^ *%> t *^^°°**® *^ ■itJ-sO 00 00 OS CN r^ r-- w rt cj <;f v^.%0 I-^CO CN O '-' (^ f^ -t- "^sO »^00 CN O ■ "^so r^OC Cs O M(Snnrt«««(sw c- :r) $' w ct ^D OCTO- 132 METEOROLOGICAL OBSERVATIONS. Pi W o U o d _o o bo ■5 u ■s S ol Ti O * '^ jj C -JUS si • . u = . [1,'C 2 *- c -^ S S ^ -g ^ S -s •" j3 ^<5-o <-s Z3 4^ *j 3 c.ti._ ^ „ - Q U Q Q li. O !/:■ QQ Q iS S S 'o Q Q '(5 O E o U i2 E Q 3 '£ U O P o 3 ^«^ ^£ 'ww^^^_ o <-% •S CO ;^^i55c/i;s2i5(5S^co^5Qw^>ui2;^^^^y^«zZc/5w:5jrt §r ^tS' t< O r-so r< c*r»':J-"**^'r3rj-rtrtiH i^ • r* fo « »* -^ 't f^"0 r* r» w ^ Cl c^ ^ ^OO r-sOO Os O M r» i-O -I- > NOVEM- METEOROLOGICAL OBSERVATIONS. 133 Pi > o e o & .-fl rt ^-s- i !^ >» o o o o c o i^ ' Ji "o _w rt "r .t: .t; . - 2 2 — 2 ~ = — .ii .t: .- 3 .- -q _2 "B .S _2 coo t; o ^ - ^ - — -- _j-5.2^-'*; 2." " 'yi « Z m 2 Q tn ? OT en Z 5 en Z en ;S q en '(5 ^ 2 > ^ > en oo 2 ^ tLJ > S S 3 , r^ f^ 0.^0 »0 M in r-- fi r*-,so rt CSWOO c< r^ t-.oo <^>nM GaosS ^m noe OOt^OP0 r-* *osO O O "^ "tOO O O mOO m ^^to^^'^^'l'^rotf) O^^ -O O t'-'O cNCNoicj^c^d^d^o'cj^oso o ;>"CNo o o cTo d"o"d'o"d'c>.CTsc^c"osr^ 5'c>"c5'ddd'do"dd'c>c>^d" •-) f. CO cTi f-o t-O "^ ^ to t^, IS W r* f. 2 ^ &^ Mr* HH H[rt -IW ■Hirt "ll-t-Icn'^i'w CN CN (>. CN CN d d" 6 CN 0" oi r^ d d <^ t! ^ ^ CO c^ -el- C*0O "* ■^ 9. 1 M <-'i 'O CO <^- CO CO CO CO n c< t* CO IH C* CO ^ w-i-O t^OO CO M M •-o ^ »0^0 r^oD c\n M r< ■>o _ M l-H IH M M M rt o« CI C* el rt « c< n C* CO DECEM- 134 METEOROLOGICAL OBSERVATIONS. ° -* * -S a ■• a; !»- 3 •S "?! ^ < 3 3 t. ti ^ ^^ c • t^ J -a ^ ^ c-a o.. p cj ? :z: O.-- ---^ ■Sw^^s^-I v7 ^ -- ^ -q >i:~ w^S2w-_;S t-1 O IJ .?■ ?r^ >«Z^QZZO^MZ2c/-;^wZ.w(5fiZ^c«^2;^c^>Z&Z( 1^ r- 6 »^*0 ra \0 O "^ f^ t^OO &. 0\0 M O O ■-< "^ "-i M- f^OO »^00 ^ c*n "o *^ *^, Ml-* W|M «-'W M]Ct Mlc^Hl^-IH ■ •-'Irt iHlC* o o 'J& CN'N'5i'>-No"oCN<*N^o'o"cNo"o0^o"d'crr\o"-vrN'>o"cvc>iCT^ 00 00 ^ 00 o^O o CN ■>.oo o\ •-< t-~.oo c^c?o«~* c*c*c^O 0\0\O.M "^^^ 00 NO o M|e hW Hf^ f*Im-KHt* Mc* Kc* Hr* OOOOnOOO OnO ^ O^ 0.00 O OvOO <0^0 C^ •- C*OC MOOO r^W to "^OO *o c rN'>->'v'?NO"o rscNCNr>,o"c>.rNo'o'o Q o'o' -^O CKC S>. O (^ S^ Cs <:>■ • n M ol c» r* r^ 'C ci (S M ri r^ r> c* f". "". f". c<, c^ n c< (•". W ct r* '*: r< r< c» cs c ta f^ •+ i^-O 1--CO On I- rt c •a c .S i5 .S c -a "~r. -o ^ '? PW 0^ J •3 IZ jj "0 r-.30 00 00 00 C^C» OOOOl^Wt^ OOtXJOOOOlC i»i rt rt , _^ U > 1 is: H . X <^ •it t-^ po Tfoo •^r»'^OOOOOt*iHrtLn*nf^r--Of4w Ovoo > r-* r^ '^ (-- c-- (^ r^oo 00 00 00 r^ r^DO 00 00 »^ t^ t^ 1^00 00 00 t^ t-- II t-3 .5? w[r< f*ir Cs -T- f^. r* »^30 CNO Ov»^»oCM^C>.-1-'ti-orj-r^o 000 rv. ij j; P3 00 ■^^ r--. r^ r- t-- f— »^oO t^r-^t^i>-r^r^r^i--r^t^ r-^00 00 r^ t^ P ^1 lC 1^ »r.00 Hrt'*rtOOO'a-t^«»^Lo»oOsOOO<^ w 'u -a J= 1^ s CSO O^OsOsCNO-OCvOsO O 0*0\OsO\0 O rt P3 fO rl r*-, ciror':rirtC«rtrtrt«rtrtc^c, >-. ^ >^>^ ^ >* 0. •S rt rt •C 13 t, u. u I-. ^'S "S^- l-"3*-'l-'^^^»-.l-■l-.L-I_. C33rtrtrtrt = 33rtrt = rtrt3rtrtrtrt(3r3 i* OJ 3 "J u U ■ 3 'U a> y ij S S ^ V^ ?1 ?, •f-^-rl c oOG^ouuuuuQiuuouUuDDOcjGouo c X-^ .s > w >> uqtq 22:^2 . 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V 1- t- t. t. u ^"2 i_uu.t-^.uH — — --'-.iMt-.r^rtr'c^N'SrJc^t^f^t'? 1 — 1 SEP- METEOROLOGICAL OBSERVATIONS. 147 r^ i^ t^ Pi H (in 00 °x *— r^ t-^«0 r^ r-* t^ r^ r- r^ r^oo r^ i^ (-. t^vo ^ »C ^O t^\0 O ^O •O vO ^o *n 'o 0000 O c*^«oCnO r-O t^i^^M r^\o nO O O^O^O OOOOO »^0 ^O O^^ sO KWf^ciclHMMfOMOOHr^clwoOOOOOOOOwr^wMc* rj c3 3 5 ™ rt rt ej Oj -J O i> o -J (D iLi O u O U c ocjoooucjcjcjoouoouaicjoooooocjooouoy .3 „www„^ w :w w'^ W ,w &w ^ ww^ ^^w tqwa; cnZZ2;cncn:n2Wu:cct«2cn2wZZWmWS2tccc2ZZ2Z r* r^j Tf »^>0 t^OO 0^ O OCTO- 148 METEOROLOGICAL OBSERVATIONS. O O c .2 1 •i & tH _o 0 "O -O t^ r-^ 1^^ t^-O ■■O NO V3 so VD S5 ^0 NO B ^ I- M It M't*^ '*^t^OO?«»o««e*^r>^t-.Ol-l rv Ov ^ NO sO ^ r^ lv.NO r^^ so NO >0 NO nC NO -o to *ONO OOM «f^O clNOr-^sfrictweflwoo Os.»hso NO 00 CNO 00 »OSO NO NO t^ Cv tv*0 sONOsONONOsOsO «0 i^.sC sO 10 ■* ^ -o 1^ ONO r^O *•* -^ndO f^C3s»nw c*:.coes'a-t^ 00 H fOC0«Ortt*e^Mc*0«^f^^-^l-lc^^^»0C^OM ^C tv c< 0000000000000000 CsO OsOsO cS t^icicvjcorncricicocir'ic^citnt^c^c^. rt ^, "^ cl c< f^, •ri u u ^ ?? >, >,>»>. t-. >-. >. ^ i-.u,uuuu'^u„u''3''^'^uu'^'^uu -"^ I- u nrtrlrtr]rt3r3C:rt3:33rtrf=i3rtrt C ;= rt rt U'-JU'JU'1^00'J5«jOOO(LI^iOO-j"J •«^^^ uUc3^oo5oo;uDooUoCoDl> oiuuu W w to; ^ fi^ww w w^ww^ww^ ■^^f s. Z^wwcom^ZcfilZlSZyiilSlZJlZiZ^cyj Zcc.^^ M rt C'O ^ i^^ t-^00 0\ M r* f^ ^ i>-,sC 1^00 0\ 00 CKO "> Q N O V E M- METEOROLOGICAL OBSERVATIONS. 14$ 1^ e4 PQ > O ^jirt''-i.iS^^;u = >» 0-.^ ^^^ ;5^ "^j-^ 'ojq's rti-*" -^ >*"3 c r^ g ^ >,» -= so S 2 u *^ 1> ^ l^ r- 1) -^ — t-C-^'^'«0*-=>^^ ** a o.Scfl-5i:'"j=3 = =3 .f^ .2 £ a E^ •0 3 2 60 jq -^ * .2 ii -O G „j JQ u ■ - -J -t- ■ H w? -s s Si as s-s s^-s X c* "^OO OS O^r^^i^t^O t^-M (^ foCNOOO M r^O BX ^ *^ t^ U-, *^- ^ ^ »0 ^ ^ »^ »^>0 ^O so »ONO ^ ^ CO ^ s << <-noo Os rt "o »0 r-- »^ f< rt O»0 w^ 0. 0. OssS OS f^ OS (3s i " •0 i^ ^ w-j »o -^ '^V<^^^-^^^^^^,Z^ ^^^ , xO rt rt r^ M '0^*4 r^for^^Tfo-jt^ij-j r>.\o rt w 00 •O ^ ^ ^ ^ -V t 't ^^^r^>^^^Z{ u^^ ^ ^ ^ 00 <^ 00 00 osO i^Osn-tO <--»^cort 'i'OsTf i »o t M r^ 00 OOOfO(^rteotj- 2 0.0^0 OOOOOOOOOOOOOOsOsO to CO CO cl t* "^ COcOfOC-.eOcOCOCO^Oc^COroco^^W c . >* >» >, ^ S !3 S S '^'^ h hi b b ^ ^ ^ 1^ ^ u u.'^ >, _^ u 4j i> nj a> ^_0_Ojj^^ oj i> «j cj li ojij 0-- 53 uouo ouGuOoouuouoooc^[5 Ti: 2 w c ■^ WW ^^^c ^^■°^^ r^%^^ 2Z ^^^^ ZZZZZZm^mc^^^ZwZZ ?* M C4 >-t C< CO v^o »-^oo cv M rt 'o ^ »o'0 «-^oo ^ n W M M 1-1 WHWMMC0 r>>o o o t>- O « ovo so l-t es «^ o^ *^oo rt e^\r) (^oo oo t^OOvOO0O<^<*-OO0Oc»Oc*OOOO ONOO OOOO^OOOOnO*^ ±- ^ ^ i^ >.!-.>-. _QJ^_^_3J_4J^J1J_4J^ o_w_aJ^^_lj o OJ O 1) 1> u u u o c C O'^ zj 0 r» io f; t^ r-- >^ f* 'f -^ ■<»• -^ '=r o w ■<(■ •* f^ ^ *n *o r^NO O O cOf^O OOO t^I^r^TTt-^ON 1^^ O ^^^O COO »or^H rt 0>0 O c0 OS I- "H >^^ . I- t- U I- ^ ^ t- I rt « rt rt 3 ~ rt ■s o_ 2 Z w r* f^ t:J- i^^O r-oo ^ O I C4 r^< '^t '^j-'O >^CO CN O I MARCH, METEOROLOGICAL OBSERVATIONS. 153 00 < >* rj -IJ •f, U-. a .2 > a. 1- 1 ^ '^ ^ ■ ^- ^- .c '- -52; ■5." "^ .S -J ^ >^ t/i ■' >, ^ i 1 g 1 1 ^ "i ^ n 3 ^ -■- tr. t. r' p:p 3: u ■ 1= P"7 rv. w r» o-j pj CNr--'^ ocr-.'^CNMH^O'Tr^i-HTtOMi^.^, wr^r^ ^ tc>o 0. ■^'a-^fn^^*^. 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CO o ax ^ r^ ^ r- O-O O O f^-^O O <^rnt^r» lo >J^ *o "^ 'o "o^O -o so »o NO vO i>.^ vO OCNO OvOvOsOOOOOOOOCNCN \0 «0 f^ t^ Vrj t>* >> i^ >. >^ t^ u \u fit fi) i> u o 11 -u '^i^^i '^.1 r'^i "^.^ ,ii rt cfl rt ;ii ^ w w w;zi c* c^ toO t^oo o o *-<*-» c: "^^ w^vO r^oo M A Y, METEOROLOGICAL OBSERVATIONS, 155 CO < e o U P5 .5.9 i^ li-i i^ 10*0 -^J 'O -O '^'O >o ^O 00 rt so (f'vOO c< O ^ 'I" «o O O NO O r^O 00000000 O 000 O WOOOOWOCN CNOO CN H CO « ui-ii^i-i:-0 r-00 c^ O *-< rt ^,sC r-~00 CN O M c» (^ -1- w-jvo t^OO 0\ O "I HI-tMIHI-IC^rtr«CtC>1C4ClC^(^C4CO(0 JUNE, 156 METEOROLOGICAL OBSERVATIONS. 00 K H^ -S '51 O O O <^ c* O 00 r^»o CnO O^ «t0 O »o*^0 t--c^»^rt r>.0 O »oCNC tHOOOOO0OC»O 0.00 Cs^O M O e^CNCsOsCs^O^C^O O CNCsO >^ J>>>^ JULY, METEOROLOGICAL OBSERVATIONS. 157 t O CO >« ^ D .3 .3 .3.3.5.5.3 'ri'ti *rt 't3 'rt rt'rt Bi oi si oe; B< o: oj ex. ON O "^ <•* K^NO r^cooOO»ot^OO»nc^ OOOOOS <^nO r^ O O O OS On 0.00 OMOOOOOONOvO«rt« OOOOnOn MWOOOO OnOnO^OOOOOOOOOnOnOOOO Ocy'ON 3 c 3 |3 S 3 S o S 3 S 3 3 S S 3 J^ iijj^ S'SS^S'SS^JiJiJi •3 _ *3 ^ *- t- t- 3 S 3 (.J rJ rt C3 'J5 O W U W l> .N.'ri.-iri.'ir^ M « eo •+ "^nO f^OO ON O M rt -o ■+ ^.nO r^ g W Z W W Z 2 X .n v3 y-j X AUGUST, ijS METEOROLOGICAL OBSERVATIONS. CO CO O < 1 *^ C4 > L^ .»i ^ o i .B 1 3 si O cso CsM«p^«^Mti>o cor-.x^rt . 't CsOO OO t^OO OOOOOOOOt^t^ HONO f^*o ii — - ^ sOM.t>. «^t^r«. r^>o >o ^ i^ r-- u O O ^>nO »of^OsOOc^(00 OOOOsC* OOOvOOWMrtOO r--oo «^ o^ o^ O s OOCNCNOOOOOOO^©\ OsO\C3sO P3 ♦■^c^c^rttOt^r^cocofOrtC* c*r*c^>N X X t>,>.>^'». •u u t- u"^ "^ u U u"^ U, ^"^ t3-Cin3-T3 ^ rtrtrjS3«rt«3r3C3 S333 '■^(L.aj_0^_4J_t;w ^ w ^ t/j (/I c/3 cc cfi U3 w M m c;: W Z w^icoco >^ M « t^- "t *nNO t^OO Ov O w c* *^ Tt L.-;\0 r^ Q Defcriptlon [ ^59 ] N° XI. Defcnpt'ion of a Machine for Meafur'mg a Ship^s Way through the Sea, by F. Hopkinson, Efquire. ^iifi783! '' I ^ H E errors and uncertainties incident to the A mariner's log, in common ufe, are too obvious not to be univerfally acknowledged. Were it not for the obfervations navigators are accuftomed to make of a fhip's progrefs, by the apparent paflage of the water along fide, and the figns that ufually prefent on approaching the land, the log, alone, would be a very unfafe dependence. Several attempts have, therefore, been made to improve the log, and render its indications more accurate, but with- out fuccefs. All the machines of this kind, that I have heard of, were compofed of a number of wheels, which were to be put in motion by the twifting of a line let out aftern, having a drag at the end fo conftrudted as to whirl round, fafter or flower, according to the motion of the Ihip. The objedlions to a machine, fo conftrufted, are, F'lrf, If the line is not very long the drag will be confiderably affefted by the fliip's wake ; and, if it is very long, the twilHngs will be irregular, and the line liable to kink. Secondly., If the drag is fo heavy as to link below the bot- toms of the waves, when the fliip fails faft, it will be too heavy, and fink too deep when {he hath but a flow pro- greflive motion : Or, othervvife, if the drag is of a proper weight Avhen Ihe makes but little way, it will fkip from wave to wave through the air when flie fails with a briflc gale, and fo be of no ufe. And, Thirdly, It will be liable to mort of the other irregularities to which the log in common ufe is expofed. Y a The i6o MACHINE for MEASURING a The machine now propofed will, It is hoped, be free from, at leaft, fome of thefe objedions. And, ahhougK it may not be able to afcertain a fliip's way through the fea to a mathematical precifion, yet if it fhould be found to anfwer the purpofe better than any inftrument hitherto contrived, it may be admitted as an acquifition to the art of navigation. This machine, in Its moft fimple form, is reprefented by Fig. I, Plate 3. Wherein AB is a ftrong rod of iron move- able on the fulcrum C. D is a thin circular plate of brafs rivetted to the lower extremity of the rod. E an horizon- tal arm conneded at one end with the top of the rod AB by a moveable joint F, and at the other end with the bottom of the index H by a like moveable joint G. H is the index turning on its centre I and travelling over the graduated arch K ; and Lisa ftrong fpring bearing againll: the rod AB and conftantly counterading the preflure upon the palate D. The rod AB fhould be applied clofe to one fide of the cut water or ftem, and fhould be of fuch a length that the palate D may be no higher above the keel than is necefTary to fecure it from injury when the vefTel is aground or fails in fhoal water. As the bow of the fhip curves inward towards the keel M, the palate D will be throvrn to a diftance from the bottom of the veflel, al- though the perpendicular rod, to which it is annexed, lies clofe to the bow above ; and, therefore, the palate will be more fairly afted upon. The arm E fhould enter the bow fomewhere near thehawfer hole, and lead to any convenient place in the forecaftle, where a fmooth board or plate may be fixed, having the index H and graduated archK upon it. It is evident from the figure, that as the fhip is urged forward by the wind, the palate D will be preffed upon by the refifting medium, with a greater or lei's force accord- ing to the progrefTive motion of the fhip : and this will operate upon the levers fo as to immediately affedt the in- dex ; making the leafl encreafe or diminution of the fhip's way S H I P's W A Y. , i6t way vlfible on the graduated arch. The fpring L always counterading the preffure upon the palate, and bringing back the index on any relaxation of the force imprefled. A fliip going through the fea opens a paffage for her- felf, making a hole in the water equal to her immerged bulk. As fhe paffes on, this vacancy is filled up by the tumbling in of the waters from each fide, and from un- derneath, at the ftern, with great violence. So that there is a fair current of water from her bow to her ftern, paf- fing under the bottom and along fide ; the force of which current is in diredl proportion to the velocity of the Ihip's progrelfive motion. This machine is, therefore, advan- tageoufly placed at the bow of the /hip, where the current firft begins, and ads fairly upon the palate ; in preference to the ftern, where the tumultuous clofing of the waters caufes a wake, vifible to a great diftance. The palate D is funk nearly as low as the keel, that it may not be influ- enced by the heaping up of the water, and the dafhing of the waves at and near the water-line. The arch K is to afcertain how many knots or miles fl^e would run in one hour, at her then rate of failing. But the graduations on this arch mart be unequal ; becaufe the refiftance of the fpring L will encreafe as it becomes more bent ; fo that the index will travel over a greater fpace from one to five miles (which I fuppofe to be a medium) than from five to twelve. Laftly, the palate, rod, fpring and all the metallic parts "of the inftrument fliould be covered with a ftrong varnifti, to prevent ruft from the corrofive quality of the fait water and fea air. IMPROVEMENT of this MACHINE. Let the rod or fpear AB Fig: r, be a round rod of iron or fteel ; and inftead of moving on the fulcrum or joint as at C, let it pafs through and turn freely in a focket, to which focket the moveable joint muft be annexed as, re— prefented i62 MACHINE FOR MEASURING a prefented in Fig. 2. The rod muft have a fhoulder to bear on the upper edge of the focket, to prevent its flipping quite down. The rod muft alfo pafs through a Hke focket at F, Fig. I. The joint of the lower focket muft be fixed to the bow of the fhip, and the upper joint or focket muft be connected with the horizontal arm E. On the top of the uppermoft focket, let there be a fmall circular plate, bearing the 32 points of the mariner's compafs ; and let the top of the rod AB come through the centre of this plate, fo as to carry a fmall index upon it, as is reprefent- ed in Fig. 3. This fmall index muft be fixed to the top of the rod on a fquare ; fo, that by turning the index round the plate, the rod may alfo turn in the fockets, and of courfe carry the palate D round with it. The little index always pointing in a diredlion with the face of the palate. The fmall compafs plate fhould not be faftened to the top of the focket, but only fitted tightly on, that it may be move- able at pleafure. Suppofe, then, the intended port to bear fouth-weft from the place of departure ; the palate muft be turned on the focket till the fouth-weft point thereon looks direftiy to the Ihip's bow ; fo that the fouth-weft and north-eaft line on the compafs plate may be precifely pa- rallel with the fhip's keel ; and in this pofition the plate muft remain during the whole voyage. Suppofe then the fhip to be failing in the diredt courfe of her intended voy- age, with her bowfprit pointing fouth-weft, let the little index be brought to the fouth-weft point on the compafs plate, and the palate D will necefl'arily prefent its broad face toward the port of deftination; and this it muft al- ways be made to do, be the fliip's failing courfe what It may. If, on account of unfavourable winds, the fliip is obliged to deviate from her intended courfe, the little in- dex muft be moved fo many points from the fouth-weft line of the compafs plate, as the compafs in the binnacle fhall fhew that fhe deviates from her true courfe. So that, in whatever direilion the fhip fliall fail, the palate D will always S H I P's W A Y. 1(53 always look full to the fouth-wefl; point of the horizon, or towards the port of deftination ; and, conlequently, will prefent only an oblique furface to the refifting medium — more or lels oblique as the fhip deviates more or lei's from the true cgurfe of her voyage. As, therefore, the refin- ance of the water will operate lefs upon the palate in an oblique than in a diredl: pofition, in exa£l proportion to its obliquity, the Index FI will not Ihew how many knots the vefTel runs in her then courfe, but will (it is expefted) indicate how many fhe gains in the diredl line of her in- tended voyage. Thus, in Fig. 5, if the Ihip's courfe lies in the direftion of the line AB, but fhe can fail by the •wind no nearer than AC ; fuppofe then, her progreflive motion fuch as to perform AC, equal to five knots or miles in one hour ; yet the index H will only point to four knots on the graduated arch, becaufe fhe gains no more than at that rate on the true line of her voyage, viz. from A to B. Thus will the difference between her real motion and that pointed out by the index be always in proportion to her deviation from the intended port, until flie fails in a line at right angles therewith, as AD ; in which cafe the palate would prefent only a thin fliarp edge to the refifting me- dium ; the preffure of which Ihould not be fulficient to overcome the fridion of the machine, and the bearing of the fpring L. So that at whatever rate the fhip may fail on that line yet the index will not be affeiled : Shewing that fhe gains nothing on her true courfe. In this cafe, and alio when the veffel is not under way, the a£tion of the fpring L iliould caufe the index to point at o; as repre- fented by the dotted lines in figure i and 4. As the truth of this inllrumcnt mufi: depend on the equal preifure of the refifting medium upon the palate D according to the fhip's velocity, and the proportionable adlion of the fpring L, there fhould be a pin or fcrcw at the joints C and F, lb that the rod may be readily unfliip- ped and taken in, in order to clean the palate from any foulnefs 564 MACHINE for MEASURING a foulnefs it may contrad:; which would greatly increafeits operation on the index H, and thereby render the gradu- ated arch, falfe and uncertain. Further, the fpring L may be expofed too much to in- jury from the fait water, if fixed on the outfide of the fliip's bow. To remedy this it may be brought under cover by conftrudling the machine as reprefented by figure 4. Where, A B is the rod, C the fulcrum or centre of its mo- tion; D the palate; E the horizontal arm leading through a fmall hole into the forecaftle: M is a ftrong chain, faft- ened at one end to the arm E and at the other to a rim or barrel on the wheel G, which by means of its teeth gives motion to the femicircle I and index H. The fpring L is fpiral and enclofed in a box or barrel, like the main fpring of a watch : A fmall chain is fixed to and palling round the barrel is faftened by the other end to the fuzee \V. This fuzee is conneded by its teeth with the wheel G, and counteradls the motion of the palate D. NN are the two lockets through which the rod A B pafies, and in which it is turned round by means of the little index R. S is the fmall compafs plate, moveable on the top of the upper focket N. The plate S hath an upright rim round its edge cut into teeth or notches ; fo that when the index R is a little raifed up, in order to bring it round to any intended point, it may fall into one of thefe notches and be detained there: Otherwife the prefl'ure of the water will force the palate D from its oblique pofition, and turn the rod and index round to the diredion in which the Ihip fhall be then failing. Should it be apprehended that the palate D, being placed fo far forward, may affed the fhip's lleerage or obllrud her failing, it ihould be conlidered that a very fmall plate will be fufficient to work the machine. I Ihould luppofe that one of three or four inches in diameter would fully anfwer the purpofe: And yet not be large enough to have any fenfible operation on the helm or ihip's way. The S H I r's W A Y. 165 The greateft difficulty, perhaps, will be In graduating the arch K; (if the machine is conftrudled as mfgiire i,) the unequal divifions of which can only be afcertained by adtual experiment on board of each fhip refpedlively; in as much as the accuracy of thefe graduations will depend on three circumftances, viz. The pofition of the fulcrum C with refped: to the length of the rod, the fize of the palate D and the ftrcngth or bearing of the fpring L. When thefe graduations, however, are once afcertained for the machine on board of any one velTel, they will not want any future alterations; provided the palate D be kept clean, and the fpring L retains its elafticity. But the unequal divifions of the graduated arch will be unneceflary, If the machine is conftrinfled as in fgure 4. For as the chain goes round the barrel L, and then winds through the fpiral channel of the fuzee W, the force of the main-fpring muft operate equally, or nearly fo, in all pofitions of the index; and confequently, the divifions of the arch K may, in fuch cafe, be equal. After all, it is not expected that a fhip's longitude can be determined to a mathematical certainty by this inftru- ment. The irregular motions and impulfes to which a fhip is continually expofed, make fuch an accuracy unat- tainable perhaps by any machinery : But if it fhould be found, as 1 flatter myfelf it will on fair experiment, that it anfwers the purpofe much better than the common log, it may be confidered as an acquifition to the art of navigation. It fhould be obferved that in afcertaining a fhip's longi- tude by a time-piece, this great inconvenience occurs, that a fmall and trifling miftake in the time, makes a very great and dangerous error in the diftance run : Whereas the er- rors of this machine will operate no farther than their real amount ; which can never be great or dangerous, if cor- rected by the ufual obfervations made by mariners for cor- re^ov JS5. SP/ff. 72 . Fjo:J4. '% r%.ii ^j. J^j'e-yJ. 'SJ7- I'/g-.K. T3pv.'-24J. Vr/." ^thytflft/ /c^f0 . Pl.t.s. Fir.H. Kr 'J "Sd?- f/o-lt. /hor.lOI. //«;•./«. />»r.2^/_^^ ^/.l^^^w- A^ i y^^/:,^ : ELECTRICAL EEL. 167 colour it is not unlike a common eel of Europe or Ame- rica, and in fliape refembles it more, except that it is thicker in proportion to its length, and the head is more flat and not lb pointed ; but differs from them in this refpecl, that it comes to the furface to breathe in the air. It is called by the Dutch Beave Ja/, and by the Englilh inhabitants the Numbing Eel. As to the other qualities, of which 1 mean chiefly to take notice, and which I think are as dif- ferent from the Torpedo of Europe, as the fifli is in fhape, they are as follows. On touching the fifli as it lies in the water in a tub pro- vided for it, a fudden and violent fnock is received, in all refpe£ts like that which is felt on touching the prime con- ductor, when charged with the elciftrical fluid from the globe; and like that chiefly, affeds the ends of the fingers and elbow. Gently holding the tail of the fifh with one hand and touching the head with the other, a very violent fhock is felt in both elbows and through the breaft and flioulders. I at firft imagined that the violence of the fhock proceeded from both arms receiving it at the fame time, and that the pain was no more than that of the two ftrokes added together; but I found myfelf miftaken. For upon feven perfons joining hands, and the firft taking hold of the tail (which may with more eafe be held than the head) and the feventh at the fame time touching the head, we were all affedted in both elbows, and that in the fame manner as I remember to have been in the eledrical expe- riment, when feveral perfons take hold of the wire and the equilibrium is reftored by the fluids paifing through their bodies. I find the fhock may be received through metallic fub- flances. On touching the fifh with an old fword blade I was ftrongly afFeded. But arming it with fealing-wax and taking hold of that part which was covered with it, the eledrical fluid (I cannot help calling it fo) would not pals. Neither has it any cfFed on the body when touched with Y 2 glafs i68 A C C O U N T or THE glafs bottle, feallng-wax, &c. Yet I cannot obferve the leafl: diminution of this quality by placing the tub which contains the filli on glafs bottles; it continues the fame in all refpe<£ls. So that whether it has an unaccountable fa- culty of collecting a quantity of the fluid from the fur- rounding waters, or through the body of the perfon toucli- ing it, or has in its own body a large fund which it can diicharge at pleafure, I am greatly at a lofs to think or imagine. Although it has no effedt on the human body when touched with a piece of wood, or indeed any other fubftance not metallic ; yet an accident difcovered to me, that on fome occafions the effect would be fenfible through wood. For one morning while I was ftandlng by, as a fervant was emptying the tub, which he had lifted intirely from the ground, and was pouring off the water to renew it, and the fifli left almoft dry, the negro received fo violent a fhock as occafioned him to let the tub fall, and calling another to his aiFiftance, I caufed them both to lift the tub free from the ground, when pouring off the remains of the water they both received fmart fhocks and were obliged to deiifl: from ernptving the tub in that manner. This I afterwards tried myfelf and received the like fhock. This fifli in- deed was one of the largeft I have feen and but newly caught. For I obferve that after being fometime confined in a tub and wanting perhaps their natural food, they lofe much of the flrength of this extraordinary quality. I am fbmetimes apt to conjecture, that this animal has the pow- er of communicating the f^roke when, and with what de- gree of force it will; and that it ferves him as a weapon of defence againfl his enemies. For I have often obferved that on firfl taking hold of it, the fhock is tolerable; but as foon as he perceives himfelf the leafl confined, it is much more violent. This I experienced to my coft, as I one day took liold of it, about the middle of the fifh, I lifted it partly out of the water, when on a fudden I received fo fmart a fhock that ELECTRICAL EEL. 169- that it occafioned a ftrong contradlion in the bending mufcles of my fingers, and I could not immediately let it go; but endeavouring to difengage my hand threw it on the ground; taking hold of it a fecond time, to return it into the tub, I was more ftrongly afFedted than ac firft, and that not only in my hands and arms, but throughout my •whole body ; the forepart of my head and the back part of my legs fufFered principally; and in the fame manner as on receiving a very fmart fliock from a highly charged phial in eleflrical experiments. On obferving that the feniation occafioned by the fliock as to the nature and degree of ftrength upon touching dif- ferent parts of the fifh, was different, I was at firft in- clined to think it might be owing to its having an extra- ordinary faculty of containing more of the tiuid in one part of its body than in another. The tail part to above one third of its length, occafions rather a numbnefs and tingling, than pain, but on applying the end of the fing- ers to the back, head, and under part of its body, it caufes a fliarp pricking pain. This may poffibly be accounted for by the difference in the texture of the furface of the fkin, as the manner of the ele(flrical fluids coming from a glafs tube is different when its iurface is altered by being rubbed with different iubftances, as has been lately taken notice of in a letter to the Royal Society. Thefc arc the principal obfervations, the fliort time 1 refided at Surinam, allowed me an opportunity of making relating to this extraordinary animal. Ohfcrv at ion's [ 170 ] N° XIII. Ohfervat'ions on the Numh Fijh-, or Torporific EeU by Henry Collins Flagg, South-Carolina. Read March f D Q mvlelf thc plcafurc, though late I con- -th, 17SJ. t r r ^ 1 • u -i- r JL tels, to comply with my promile or commu- nicating fome obfervations on the Numb Fifh, or Torpo- rific Eel, which I think a more proper name. Thefe ob- fervations are contained in two letters I had the honor to write to the Rev. Dr. Stiles, a member of your philofo- phical fociety, from Rio Eflequebo. Pleafe to accept the following extrad:s. The apparent difference between the torporific eel and that ufually caught in your harbour is, the former is flatter on the back and head, the upper part of which is perfo- rated with feveral holes*, and has on each fide, behind, a fmall fin which fome fay are elevated or depreffed as the fifh is pleai'ed or notf ; the body I think is larger in pro- portion to the length, and it has a broad fin connedled to the belly and continued to the tail. I have feen this fifh four feet long. The fenfation occafioned by touching it appeared to me exadly fimilar to an eled;ric fhock. I have as yet been able to procure only one of thefe eels, and that was injured by laying too long dry before it came to me. The following are the remarks I made the little time it lived. I received the fifh from a negro in a wicker bafket, and laying it on the ground felt a confiderable fhock, as I did too when I turned the fifh out of the bafket into a tub of * Thefe holes do not penetrate to the mouth, nor could I difcover the ufe of them. But 1 ■was not fufficiently exa6t In my difle<5tioii of tlic head, or I Uunk. 1 miijht Juive found the tcr- Jnjnation of thefe du^ils, f Thib is true. T O R P O R I F I C E E L. ijr of water. The fhock is greater if the fifli is enraged; but whether repeated touches will exhaufl. this ftrange power, as frequently repeated bites do the viperine and fome other poifons for a time, I believe no experiment has yet deter- mined*. If a perfon hold his finger in the water feveral inches diftant from the fifli and another touch it, a fliock equally fevere is felt by him who does not touch it. The fame thing happens if the fiHi exerts itfelf without being touched. If a number of perfons join hands, and one touch the eel, they are all equally fhocked, unlefs there fliould happen to be one of the number incapable of being affeifled by the eel, which is the cafe of a very worthy lady of my acquaintance, who can handle this filh at will. I am informed fome Indians and negroes can do the fame ; whether by the affiftance of any means to counteract the power of the eel, I know not ; but am perfuaded it is Ibmething in the conftitution of the ladyj". The eel I had obtained got out of the tub, and it was with fome difficul- ty I returned it, for the repeated Ihocks I received through a piece of deal board eighteen inches long, with which 1 attempted to lift it, made my arms ache very much, and for a confiderable time. I think the numbnefs occafioned by touching this eel continues longer than that from an eledric fliock of the fame degree of force, and I have been allured by a perfon of good ienfe and veracity, that a ne- gro fellow formerly being bantered by his companions for his fear of this eel, determined to give a proof of his re- folution, and attempted to grafp it with both hands. The unhappy coniequence was, a confirmed paralyfis of both arms. 1 hear this fellow is ftill living in the illand of St. Chrirtopher's ; if ib, I can obtain more fatisfadlion, for I have my, doubts of the negro's honeftyij;. But very cer- tain * I am fir.ce convinced they do. f This lady, when I became acquainted with her, was far gone in an heel'ue femitones of the octave ; thefe I had perfedly tuned; and as they will not be fenfibly af- B b fcfted I90 IMPROVEMENT in the fedled by any change of weather, they remain as ftandards, 1 take it for granted that any perfon at all accuflomed to mufical founds can tell when one tone is in 7inijbn with another; and that a very little pradice will enable him to tune one found an ofiave to another, thefe conchords are fo manifeft that they cannot eafily be miftaken. There is then nothing to be done but to tune the twelve firings in uni- fon with the twelve forks ; this will fix the fcale, or tem- perature for one odave, which is the whole difficulty ; the reft of the inftrument is eafily tuned by unifons and oc- taves to the fcale, fo afcertained*. Having, I hope, fully accomplifhed the defign I had in view when I turned my thoughts to this fubjed, I fhall now take leave of it ; and fhall be highly gratified if I find others benefited by my attentions, although in a mat- ter of no very ferious import. Nov. 1784. Defer iption of a further Impro'veinent in the Harp- sichord. Rei 2 •'^J^""^''y IN a former paper read before the fociety, refpeding an improved method of quilling a Harpsichord, I made fome apology for troubling you with a fubjed not ftridly within the limits of your view as a philofophical fociety, and which might appear to fome of fmall importance. At the fame time I took formal leave of a purfuit which had accidentally engaged my attention, and which I had obtruded upon your's. Notwithftanding this, I find myfelf under a neceffity ot again requefting your indulgence, whilft I defcribe a difcovery I made in Auguft laft, of a flill further improvement to the fame purpol'e. ' Having; My fct of forks are tuned fiom the middle C (harp to the C ahove, iuchifive, HARPSICHORD. 191 Having fucceeded to the extent of my expedatlon in a more advantageous way of applying the crow quill in com- mon ufe in a harpfichord, I thought to reft content with that improvement; which had principally for its obje£l the duration of the quill's elafticity, and of courfe the durati- on of the equality of touch. But notwithftanding the long eftablifhed prejudice in favour of the crow quill, and the prevailing opinion that no fubftance can fupply its place to advantage, I think a candid critic will allow that one of the following pofitions is founded in fadl, and the other in reafon. Firjl. Although the three flops of a harpfichord fliould be quilled to the heft advantage, the refult of the whole will be an obfervable iingle or tinkling between the quills and wires, which depreciates the dignity and fweetnefs of the inftrument. The beft harpfichords are fo cenfurable for this imperfctftion, that the Forte Piano, which is free from it, ftands a chance of rivalling that noble inftrument, for this caufe only ; being far inferior in every other refpedl. Second. Is it not reafonable to fuppofe that fo long a ftring, fo advantageoufly ftretched over fo large a box, Ihould yield a greater body of tone, than that which is produced by the impulfe of a quill ? If the quill be made very ftiff, this will render the touch difagreeable and en- creafe the jingle, but not add to the body of tone. One reafon why the quill does not draw a fuller tone from the ftring, I fuppofe to be the fmallnefs of its contact. The back of a quill is a portion of a circle, the extended ftring is a right line, and a circle can touch a right line only in a point ; the contail therefore muft be fo very fmall, that mere ftrength of impulfe is not fufficient to put the ftring into full vibration. The method I am now to defcribe of quilling, or rather tonguing a harpfichord, I have found by experiment, to draw forth the powers of the inftrument to a furprifing B b 2 effect, 192 IMPROVEMENT in the efFed;, caufmg it to yield a full and pure body of tone,, free from all jingle and very pleafant to the ear. N. B. What hath hitherto been called the tongue of the jack, I lliall denominate the palate ; and the fubftltute I have made for the quill, I Ihall call the tongue. The propriety of this will appear in the defcription. Let A, figure 1 2, reprefent the palate in front. Mate III. .^^,jjj^ ^ mortife cut through it for the tongue to work in. B, is the tongue, having two fmall holes drilled through it, one in the centre of its motion and the other at a little diftance behind, for the reception of one end of a wire fpring hereafter mentioned. Figure 1 3, is the palate in profile, with the tongue pro- perly mounted and moveable on the centre pin. This figure alfo fhews how the palate muft be hollowed in be- hind to expofe the root of the tongue, and the fmall hole in it for the reception of one end of the wire fpring. Figure 14, is a back view of the palate, fhewing the groove in which the hair fpring of the jack lies, and a, fmall wire ftaple at b, to which the lower end of the fteel fpring is to be faflened. Figure 15, is the fpring which is to govern the tongue. It muft be of fine fteel wire, fomewhat annealed by being forcibly rubbed between pieces of leather or cork, and is formed by winding the vv'ire backwards and forwards with a tight hand, over pins driven deep and firm into a piece of wood. As the palate muft play freely within the fork or jaws of the jack, the windings of the fpring muft not exceed the width of the palate. The upper end of the fpring being run through the fmall hole in the root of the tongue'and bent round, fo as to fecure it, and the fuper- fluous part cut off; the lower end ofthefime fpring muft be run under the little ftaple [b-, figure 14,) and bent up- wards with a gentle ftrain, fo as to hook it on and fecure it to that ftaple ; the fpring will then operate with all its elafticity, and the tongue will be fubjedled to its operation. Figure HARPSICHORD. 195 Figure 1 7, reprefents the palate in a back view with the zig zag fpring fattened by one end to the root of the tongue, and by the other to the little ftaple. To prevent the tongue from rifing by the force of the fpring above a horizontal pofition, there muft be a wire ftaple driven in the front of the palate immediately above the tongue (as at a, in figure 12 and 13;) and the tongue, if of wood, fhould be armed with a fmall piece of foft lea- ther juft under the ftaple, to prevent noife. It muft be left to future experiment to determine the moft proper of all fubftances of which the tongue fliould be made; different fubftances drawing diff"erent tones from the ftring. After many effays to thin purpofe, I have con- cluded to furnifli my harpfichord in the following manner. The tongues of the firft unifon are of DenJ'olc-lcather. Thofe of the fecond are of a foft leather faced with Mo- rocco, fuch as is frequently ufed in harpfichords, though applied in a different way, and the tongues of the odave are of wood, fuch as pear tree, laurel, or any wood of au even grain and not too hard in fubftance. But all mount- ed on Iprings, as above defcribed, and their faces well po- lifhed with black lead where they come in contact with the ftrincs. My reafons are. The fole-leather produces a full, fweeC and vigorous tone from the firft unifon. The fecond uni- lon, which is the piano of the inftrument when the pedal is prefled, is furniflied with Morocco leather, which draws a full but more foft and fmothered tone from the ftrincr. And the oGave is ftruck with wooden tongues for the fake of vivacity or brilliancy, which is the genius of that ftop ; yet I am n:-t fure but that the o£lave alfo had' better be- ilruck with fole-leather, like the firft unifon*. A harpfichord thus furniihed, will produce a body or" quantity of found, and a purity of tone, that will aftoniih at * Becaufe, after the (Iroke has been given, tlie wooden tongue rcpafling the flrjng, yet in-i vibration, makes a jingle, which the leather tongues do not.. 194 IMPROVEMENT in the HARPSICHORD. at the firft hearing, much refembling the diapafon ftop of an organ. And it is manifeft that if the touch be well regulated at firft, it will not afterwards be fubjedt to alte- ration for a long courfe of time. The touch is in part re- gulated by the ftrength of the ferpendne fpring and the number of its zig zag evolutions ; and in part by the man- ner of rounding off the tip of the tongue ; for the tip of the tongue muft not be cut off fquare, (in which cafe, the firing would leave the tongue too abruptly and caufe a dif- agreeable twang,) but fhould be flanted off from under- neath, and its extreme point rounded and well polifhcd by rubbing it very hard with a piece of black lead. As to the ftrength of the fpring, four fizes of wire, viz. from n°- 4 to n°- S, will be fufficient for the whole inftrument; but the touch is more immediately regulated by rounding off the tips of the tongues by the preffure and polifh of the black lead, more or lefs, as occafion fliall require. When the tongues are of wood, a ftroke or two of a fine file will be neceflary to take off the fquare edge left by the knife, previous to the polifhing it with the black lead. After all, a harpfichord juft furniflied in this way, will not be fo pleafant to the touch or to the ear as it will be after a few weeks ufe ; when the ftrings will, by repeated fridlion, have rounded off and polifhed the tips of the tongues, and have made for themfelves a broad bearing or contaft, which cannot perhaps be fo accurately produced by any care of the workman. Laftly, it is fcarce neceffary to obfervc that the ferpen- tine fpring and the root of the tongue muft be comprifed within the thicknefs of the jack ; otherwife they will be apt to interfere with the firing behind, when the ftop is puftied back. F. HOPKINSON. Obfervations [ 195 ] N° XX. Ohfervations on a Comet lately difconjered; commiin'icated /y David Ritten house, Efquire. Read Mar. d^'\^ tlic 2 1 ft of January laft, John Lukens, 19. 17 A- \^^ Efquire, informed me that he had diicover- ed a comet the preceding evening, and on the evening of "the fame day, afhfted by Mr. Lukens and Mr. Prior, I obferved the apparent place of the comet to be in the 15th degree of Pifces, with 16° 6' fouth latitude. By fubfe- quent obfcrvations I found its motion to be north eafterly, with refped to the ecliptic, and that its neareft approach to us had preceded our firlt obiervation. It pafled the ecliptic on the 31ft in the 25° of Pifces, and February the 17th it was in Pifces 29'^ with 13° 10' north latitude. This was the laft time I faw it, clouds and moonlight having fince prevented. The light of this comet was fo very faint that it was impoflible to obferve it with accuracy, at leaft without bet- ter inftruments than I am pofleffed of, efpecially as the comet was always involved in day light, moonlight or the thick atmofphere of the horizon. No pains or attention however were wanting, and from the beft ohfervations I could make, I find it paifed its perihelion about the 20th of January, its diftance from the fun being about _\- of the fun's diftance from us. The place of its afcending node is in the 25th deg. of Taurus, and the inclination of its orbit 53''. Its motion is retrograde, that is, contrary to the or- der of the figns. I have ftill hopes of feeing it in the morning, though its diftance is now fo very great that it can fcarcely be vifible to the naked eye. Extra^' I 196 1 N° XXI. ExtraEi of a Letter from the Rev. Jeremy Belknap, co7itaining Obfervations on the Aurora Borealis. Dover, New-Hampfliire, March 31ft, 1783. Read May n | ^ ID you cvcr, in obferving the Aurora Bo- £ p realis, perceive a found? I own I once looked on the idea as frivolous and chimerical, having heard it at firft from perfons whofe credulity, I fuppofed, exceeded their judgment ; but, upon hearing it repeated- ly, and from fome others whom I thought judicious and curious, I began to entertain an opinion in favour of it. I was ftrengthened in this opinion about two years ago, by liflening with attention to the flafhing of a luminous arch which appeared in a calm frofty night, when I thought I heard a faint ruftling noife like the brufliing of filk. Laft Saturday evening I had full auricular demonftration of the reality of this phenomenon. About ten o'clock the hemi- fphere was all in a glow ; the vapours aicended from all points, and met in a central one in the zenith : All the difference between the fouth and north part of the heavens was, that the vapour did not begin to afcend fo near the horizon in the fouth as in the north. There had been a fmall fhower with a few thunder claps, and a bright rain- bow in the afternoon ; and there was a gentle weftern breeze in the evening which came in flaw-s, with intervals of two or three minutes ; in thefe intervals 1 could plain- ly perceive the ruflling noife, which was eafily diftinguifh- able from the found of the wind, and could not be heard till the flaw had fubfided. The flafhing of the vapour was extremely quick j whether accelerated by the wind I cannot EXPERIMENTS on the SWEET SPRINGS. 197 cannot fay ; but from that quarter where the greatefl: quan- tity of the vapour feemed to be in motion, the found v. as plaineft; and this, during my obfervation, was the eaftern. The fcene lafted about half an hour, though the whole night was as light as when the moon is in the quarters." N° XXII. A Letter from J. Madison, E/q. to D. Rittenhouse, E/q. containing Experunents and Ohfer'vations upon ivhat are commonly called the Siveet Springs, THESE waters rife on the north fide of a large moun- tain at the foot of it, called the Sweet Spring Moun- tain, in the county of Botetourt. The fouth fide is co- hered with ftones of an ocrous appearance. In many places iron ore may be found; but on the north the moun- tain is fertile, covered with a rich mould, at leaft near the fpring. The remarkable efficacy of thefe waters in many diforders, efpecially, it is faid, in confumptive complaints, firft induced me to attempt their analyfis. Such experi- ments as I had time and opportunity to make, I fhall faith- fully relate, and leave it to others, better qualified than myfelf, to judge of their merits. Experiment i. Having plunged a very fenfible mer- curial thermometer in the fpring, it flood at 73°- The temperature of air was about 69. 2. A good hydrometer funk one-twentieth of an inch deeper in common mountain water, than in the fpring. 3. Nut-galls mixed with the water in a wine glafs ftruck a palifli brown, which fhewed that there was little or no iron in it. 4. Violets mixed with the water in a wine glafs, turn- C c ed 198 EXPERIMENTS on the SWEET SPRINGS. ed it in a fliort time of a redclifh colour. This was a proof that the waters contained fome kind of acid. 5. Having made a folution of filver in the nitrous acid, and mixed a little of it with the \Aater, it immediately be- came milky, and a white pulvurent precipitate enfucd. This experiment fhewed by the whitenefs of the precipi- tate, that the waters contained nothing fulphureous, and by the pulvurency of the precipitate that the acid contain- ed in the waters was vitriolic. 6. A folution of lead in the nitrous acid being mixed with the water, it became fomewhat milky, and a white precipitate was obferved. This experiment alfo fliews that the waters contain an acid, moft probably the vitriolic, and alfo that they contain calcareous earth. Soap is not readily mifcible wuth them. 7. A folution of faccharum faturni in the nitrous acid being made, and lines marked upon paper with it, and placed over the water, the lines retained their former co- lour. This experiment alfo {hews that the water contains nothing fulphureous. 8. Having poured a little of the fpirit of fait into the water, after fome time a coloured precipitate was obferved, but as the waters did not flrike a green or blue colour, it iliewed that there was no copper in them. 9. A folution of vitriol of copper mixed with the water produced a thick, green, curdly appearance, but did not become bluer. This experiment fliewed that there was no vol. alkali contained in them. 10. The vitriolic acid mixed with the water fuddenly effervefced, and produced a heat which raifed the ther- mometer from 75 to 83, by applying the bulb to the outiide of the glafs. 11. As the fpring is continually difcharging large bub- bles of air, which rifmg from the bottom break upon the furface of the water, I was defirous of making fome experiments upon the air, in order to determine whether the EXPERIMENTS on the SWEET SPRINGS, i 99 the acidity of the water might not he owing to it ; and alfo to determine the nature of the air, whether fixed or not. Having therefore caught a quantity of the air in a decanter, I communicated a part of it to an equal bulk of pure mountain water, and after agitating them for fome time, gave it to feveral to tafte ; who agreed that it had the tafte of the fpring water. Upon a fecond trial this ex- periment did not fucceed. I had not an opportunity of trying the nature of the air by means of chalk-water, and was prevented from profecuting any farther enquiries into the nature of thefe celebrated waters by a fudden alarm, to which the frontiers were then continually expofed. Thefe waters have been falfely called Jhi'ect-, for their tafte is evidently acidulous. The experiments alfo ihew that they contain an acid. Their tafte refembles exactly that of waters artificially impregnated with fixed air, ex- tricated from chalk, by means of the vitriolic acid, and I conceive muft be nearly the fame with the true Pyrmont water. They have little or no fmell, do not form an in- cruftation, nor do they leave a depofit upon ftanding many hours. Upon bathing in the morning, the flcin has a foapy kind of feel. This was not obferved in the evening. There is near this fpring another, a very ftrong cha- lybeate. I am, with great regard, yours, J. MADISON. N° XXIII. A Letter from the Rev. J K R E m Y B e l K N a p, on the prefernj'mg of Parfnips by drying, Dover, New-Hampfliire, March 5, 1784. SIR, Read Apr. A M O N G thenumbcr of efculent roots, the ,16, i7»4- j-^ pmfiiip has two fingular good qualities. C c 2 One 200 On preserving PARSNIPS. One is that it will endure the fevereft froft and may be taken out of the ground in the Ipring, as frelh and fweet as in autura; the other is that it may be preferved by drying to any defired length of time. The firfl: of thefe advantages has been known for many years paft; the people in the moft northerly parts of New-England where winter reigns with great feverity, and the ground is often frozen to the depth of two or three feet tor tour months, leave their parfnips in the ground till it thaws in the fpring, and think them much better preferv- ed than in cellars. The other advantage never occurred to me till this winter, when one of my neighbours put into my hands a fubilance which had the appearance of a piece of buck's horn. This was part of a parfnip which had been drawn out of the ground laft April and had lain neglected in a dry clofet for ten months. It was fo hard as to require confiderable ftrength to force a knife through it crofs-wife; but being foaked in warm water, for about an hour, became lender, and was as fweet to the tafte as if it had been frelh drawn from the grounds As many ufeful difcoveries owe their origin to accident, this may fuggeft a method of preferving fo pleafant and wholefome a vegetable for the ufe of feamen in long voyages, to prevent the fcurvey and other diforders inci-, dent to a fea-faring life, which is often rendered tedious and diftrefling for want of vegetable food; fince I am per- fuaded that parfnips dried to fuch a degree, as above relat- ed, and packed in tight catks, may be tranfported round the globe, without any lofs of their flavour or diminution of their nutritive quality. I am fir, your humble fervant, JEREMY BELKNAP. Jn [ 20I J N° XXIV. An Optical Problem^ propo/ed by Mr. Hopkinson, andfolved by Mr. Rittenhousi;. Philadelphia, March l6ih, 1785. DEAR SIR, Read Feb. T T A K E thc liberty of requefting your attentl- ''' ''^ ' X on to the following problem in optics. It is I believe entirely new, and the folution will afford amufe- ment to you and inftruftion to me. Setting at my door one evening lafl fummer, I took a filk handkerchief out of my pocket, and ftretching a por- tion of it tight between my two hands, I held it up be- fore my face and viewed, through the handkerchief, one of the flreet lamps which was about one hundred yards diftant; expecting to fee the threads of the handkerchief much magnified. Agreeably to my expedtation I obferv- ed the filk threads magnified to the fize of very coarfe .wires; but was much furprifed to find that, although I moved the handkerchief to the right and left before my eyes, the dark bars did not feem to move at all, but re- mained permanent before the eye. If the dark bars were occafioned by the interpofition of the magnified threads between the eye and the flame of the lamp, I fliould have fuppofed that they would move and fucceed each other, as the threads were made to move and pafs in fucceffion be- fore the eye; but the fail was otherwife. To account for this phenomenon exceeds my fkill in.' optics. You will be fo good as to try the experiment, and if you find the cafe truly ftated, as I doubt not you' will, I fliall be much obliged by a folution on philofophi— cal principles. I am fir, with great fincerity. Your moft cfi^edionatc friend, And very humble fervant, F. HOPKINSON.. 202 A PROBLEM in OPTICS. ^ The Anfwer-, by Mr. Ri'ttenhouse. DEAR SIR, H E experiment you mention, with a filk handker- chief and the diftant flame of a lamp, is much more curious than one would at hrft imagine. For the objed we fee is not the web of the handkerchief magnified, but fomething very different, as appears from the following confiderations. iff. A diflinil image of any objc£t, placed clofe to the eye, cannot be formed by parallel rays, or fuch as iffue from a diftant luminous point : for all fuch rays, paffmg through the pupil, will be colleded at the bottom of the eye, and there form an image of the lumi- nous point. The threads of the handkerchief would only intercept part of the rays, and render the image lefs bril- liant. 2dly. If the crofs bars we fee were images of the filk threads, they muft pafs over the retina, whilft the threads are made to pafs over the pupil ; but this, as you obferve, does not happen ; for they continue ftationary. 3dly. If the image on the retina was a picture of the ob- jed before the eye, it muft be fine or coarfe, according to the texture of the handkerchief. But it does not chanee with changing the filk, nor does it change on removing it farther from the eye. And the number of apparent threads remains the fame, whether lo, 20, or 30 of the filk threads pafs acrofs the pupil at the fame time. The image we fee muft therefore be formed in fome different manner ; and this can be no other than by means of the vifleclion of light in paffmg near the furfaces of bodies, as defer ibed by Newton. It is well known in optics that different images of the different points of objeds without the eye are formed on the retina by pencils of rays, which, before they fall on the eye, are inclined to each other in fenfible angles. And the great ufe of telefcopes is to encreafe thefe angles, re- gularly, in a certain ratio ; fuffering fuch rays as were parallel A PROBLEM IN OPTICS. 20^ parallel before they enter the telefcope to proceed on, pa- rallel, after paffing through it. The extended image which we fee in this experiment muft therefore be formed by pencils of rays, which before they entered the eye, had very confiderable degrees of inclination with refpeft to each other. But coming from a fmall diftant flame of a lamp, they were nearly parallel before they palled through the lilk handkerchief. It was therefore the threads of lilk which gave them fuch different dire£tions. Before the filk is placed to the eye, parallel rays of light will form a fingle lucid fpot, as at A, Plate III. Figure 16. And this fpot will ftill be formed afterwards by fuch rays as pafs through the little mefhes uninfluenced by the threads. But fuppofe the perpendicular threads by their aclion on the rays, to bend a part of them one degree to the right and left, another part two degrees ; there will now be four new images formed, two on each fideof the original one at A. By a funilar action of the horizontal threads, this line of five lucid points will be divided into five other lines, two above and two below, making a fquare of twenty-five bright fpots, feparated by four perpendicular dark lines and four horizontal ones ; and thefe lucid fpots and dark lines will not change their places on moving the web of filk over the eye parallel to any of its threads. For the point of the retina on which the image fliall fall is determined by the incidence of the rays, witli refpedt to the axis of the eye, be- fore they enter, and not by the part of the pupil through which they pafs. In order to make my experiments with more accuracy, I made a fquare of parallel hairs about half an inch each way. And to have them nearly parallel and equidiftant, I got a watchmaker to cut a very fine fcrew on two pieces of fmall brafs wire. In the threads of thcfe fcrews, 106 of which made one inch, the hairs were laid 50 or 60 in number. Looking through thefe hairs at a fmall opening in the window fhuttcr of a dark room, -j\- of aii inch wide and. 204 A PROBLEM in OPTICS. and three inches long, holding the hairs parallel to the flit, and looking toward the fky, I faw three parallel lines, almoft equal in brightnels, and on each fide four or five others much fainter and growing more faint, coloured and indiftind, the farther they were from the middle line, which I knew to be formed by fuch rays as pafs between the hairs uninfluenced by them. Thinking my apparatus not fo perfed as it might be, I took out the hairs and put in others, fomething thicker, of thefe 190 made one inch, and therefore the fpaces between them were about the -4^ part of an inch. The three middle lines of light were now not fo bright as they had been before, but the others were rtronger and more diftindt, and I could count fix on each fide of the middle line, feeming to be equally diftant from each other, eftimating the diftance from the centre of one to the centre of the next. The middle line was ftill well defined and colourlefs, the next two were likewife pretty well defined, but fomething broader, having their inner edges tinged with blue and their outer edges with red. The others were more indiftindl, and confifted each of the prifmatic colours, in the fame order, which by fpreading more and more, feemed to touch each other at the fifth or fixth line, but thofe neareft the middle were feparated from each other by very dark lines, much broader than the bright lines. Finding the beam of light which came through the win- dow fhutter divided into fo many diftindt pencils, I was defirous of knowing the angles which they made with each other. For this purpofe I made ufe of a fmall prif- matic telefcope and micrometer, with which I was favour- ed by Dr. Franklin. I faftened the frame of parallel hairs before the objed: glafs, fo as to cover its aperture entirely. Then looking through the telefcope, I meafured the fpace between the two firft fide lines, and found the angular diftance between their inner edges to be 13', 15"; from the middle of one to the middle of the other 15' , 30", and from A PROBLEM IN OPTICS. 205 -from tlie outer edge of one, to the outer edge of the other 17', 45". In the firft cafe I had a fine blue ftreak in the middle of the objed, and in the laft a red ftreak. The other lines were too faint, when feen through the telefcope, to meafure the angles they fubtended with accuracy, biit from fuch trials as I made I am fatisfied that from the fe- cond line on one fide to the fecond on the other fide, and fo on, they w^ere double, triple, quadruple, &c. of the firll angles. It appears then that a very confiderable portion of the beam of light paifcd between the hairs, without being at all bent out of its firft courfe ; that another fmallcr porti- on was bent at a medium about 7', 45" each way ; the red rays a little more, and the blue rays a little lefs ; an- other ftill fmaller portion 15', 30" ; another 23', 15", and fo on. But that no light, or next to none, was bent in any angle lefs than 6', nor any light of any particular colour, in any intermediate angle between thofe which arife from doubling, tripling, &c. of the angle iu which it is bent in the firft fide lines. I was furprized to find that the red rays are more bent out of their firft diredlion, and the blue rays lefs; as if the hairs adted with more force on the red than on the blue rays, contrary to what happens by refradlion, when light pafies obliquely through the common furface of two dif- ferent mediums. It is, however, confonant to what Sir Ifaac Newton obferves with refpe(fl to the fringes that border the fhadows of hairs and other bodies ; his words are, " And therefore the hair in caufing thefe frin ;es, " aited alike upon the red light or leaft refrangible rays *' at a greater diftance, and upon the violet or moft re- " frangible rays at a lefs diftance, and by thofe adions " difpofed the red light into larger fringes, and the violet *' into fmaller frinc-es." By purfuing thefe experiments it is probable that new and interefting difcoveries may be made, refpecting the D d properties 2o6 ENQUIRY into the CAUSE of properties of this wonderful fubftance, light, which ani- mates all nature in the eyes of man, and perhaps above all things difpofes him to acknowledge the Creator's boun- ty. But want of leifure obliges me to quit the fubjed: for the prefent. I am, dear fir, your affedionate friend, And very humble fervant, DAVID RITTENHOUSE. N° XXV. An Ejiquirj into the Caiife of the Increafe of Bilious and Intermitting Fevers in Pennfyl'vania^ nvith Hints for frequenting them. By Benjamin Rush, M. D. Pro- feffor of Chemiflry in the Univerfity of Pennfylvania. Read December -H-T ^35 bceu remarked, that Pennfylvania for fonie years part has become more fickly than 16, 1785. . I . formerly. Fevers which a few years ago appeared chiefly on the banks of creeks and rivers, and in the neighbour- hood of mill-ponds, now appear in parts remote from them all, and in the higheft fituations. This change with rciped to the healthinefs of our country, may be traced to the three following caufes. 1. The eftablifliment and increafe of mill-ponds. There are whole counties in Pennfylvania in which intermittents were unknown, until the waters in them were dammed, for the purpofe of eredling mill-ponds. 2. The cutting down of wood, under certain circum- ftances, tends to render a country fickly. It has been re- marked that Intermittents on the fliores of the Sufquehan- nah have kept an exaft pace with the paflages which have been opened for the propagation of marfh effluvia, by cutting BILIOUS AND INTERMITTING FEVERS. 207 cutting down the wood which formerly grew in its neigh- bourhood. I remcmljer the time, when inlermittents were known only within half a mile, in fome places, of that river. They are now to be met with ten miles from it in the fame parts of the ftate. I beg a difti notion to be made here between clearing and culli-vatiiig a country. While clearing a country makes it fickly in the manner that has been mentioned, cultivat- ing a country, that is, draining fwamps, dellroying weeds, burning brufh, and exhaling the unwhoHbme or fuperflu- ous moifturc of the earth, by means of frequent crops of grain, graifes, and vegetables of all kinds, render it heal- thy. I could mention, in fupport of thefe fa£ts, feveral countries in the United States, which have palled through each of the ftages that have been defcribed. The hrft fet- tlers received thefe countries from the hands of nature pure and healthy*. Fevers foon followed their improvements, nor were they finally banilhed, until the higher degrees of cultivation that have been named took place. I confine myfelf to thofe countries only where the ialutary effects of cultivation were not rendered abortive by the neighbour- hood ot mill-ponds. A 3d caufe of the late increafe of bilious and intermit- ting fevers, muft be fought for in the difl"erent and une- qual quantities of rain which have fallen within thci'e laft feven years. While our creeks and rivers, from the uni- formity of our feafons, were confined to fteady bounds, there was little or no exhalation of febrile miafmata frona their fhores. But the dry fummers of 1780, 1781, and 1782, by reducing our creeks and rivers far below their ancient marks ; while the wet fprings of 1784 and 1785, by fwelling them both beyond their natural heights, have, when they have fallen, as in the former cafe, left a large D d 2 and * A phyfician who travelled throuf^h part of Bedford count)-, in Pcnnfylvania, in the year 1782, informed me that he was witnefs of fomc country people liaving travelled twenty miles, to fee wlutliei- it was poflible for a German girl who laboured under an intermittent, to be'' UOT and cuLU at the fame time. 2o8 ENQUIRY into the CAUSE of and extcnfive furface of niolfl ground expofed to the ac- tion of the fun, and of courfe to the generation and exha- lation of febrile miafmata. The hiftory of epidemics irr foreign countries, favours this opinion of the caule of their increafe in Pennfylvania. The inhabitants of Egypt are always healthy during the overflowing of the Nile. Their fevers appear only after the recefs of the river. It is re- markable that a wet feafon is often healthy in low, while it is fickly in hilly countries. The real'on is obvious. In the former the rains entirely cover all the moift grounds, while in the latter, they fall only in a fufficient quantity to produce thofe degrees of moifture which favour febrile exhalations. The rains which fall in the fummer are ren- dered harmlefs only by covering the xvhole furface of marfhy ground. The rains which fall in our ftate after the middle of September, are fo far from producing fevers, that they generally prevent them. The extraordinary healthlnefs of the laft autumn, 1 believe was occafioned' by nothing but the extraordinary quantity of rain that fell during the autumnal months. The rain probably afts at this feafon by diluting, and thus deftroying, the febrile miafmata that were produced by the heat and moifture of the preceding fummer. In fupport of the truth of this third caufe of the increafe of fevers in Pennfylvania, I have' only to add a fa£t lately communicated to me by Dr. Franklin. He informed me that in his journey from Pafly to Havre de Grace, laft fummer, he found the country through which he travelled, unufually fickly with fevers. Thefe fevers it was generally fuppofed, were produced by the extraordinary dry weather, of which the public papers- have given us fuch melancholy and frequent accounts. I come now to fuggeft a few hints for obviating and preventing fevers, and for rendering our country again healthy. For this purpofe I beg leave to recommend in the firft place, the planting of trees around all our mill- ponds, (befides cleaning them occafionally) in order to prevent BILIOUS AND INTERMITTING FEVERS. 209- prevent the difeafes that have juftly been afcrlbed to them. Let the trees be planted in the greateft number, and clofeft' together, to leeward of the ordhiary current of the fum- mer and autumnal winds. I have known feveral inftances of families being preferved from fevers by an accidental copfe of w^ood ftanding between a mill-pond and a dwell- ing houfe, and that in cafes too where the houfe derived no advantage from an high fituation. The trees aronnd or near a mill-pond, a£t perhaps in a fmall degree mecha- nicnlly. By fheltering the pond from the adion of the fun, they leiTen exhalation, as well as obllruft the palfage of the vapors that are railed to the adjacent parts. But they aft likewife chemically. It has been demonflrated that trees abforb unhealthy air, and difcharge it in a high- ly purified ftate in the form of what is now called " de- " flogifticated" air. The vpillow tree, according to Mr. Ingenhaufz, has been found to purify air the moft rapidly of any tree that he fubjedted to his experiments. The ra- pidity of its growth, its early verdure, and the late fall of its leaf, all feem to mark it likewife as a tree highly pro- per for this purpofe. A fecond method of preventing fevers, is to let the cul- tivation always keep pace with the clearing of our lands. Nature has in this inftance conne(£led our duty, intereft and health together. Let every fpot covered with moifture from which the wood has been cut, be carefully drained, and afterwards ploughed and fowed with grafs feed; let weeds of all kinds be deftroyed, and let the waters be fo directed as to prevent their ftagnating in any part of their courfe. Thefe are the two principal means of extirpating inter- mitting and bilious fevers from our country, but as thefe means are flow in their operation, I fhall fubjoin a few" diredions for preventing fevers till the above remedies. can take effed. i;.. Whetherr 2IO ENQJJIRY INTO THE CAUSE of 1. Whether the matter which produces fevers be of an organic, or inorganic nature, I do not pretend to deter- mine, but it is certain, that fire or the fmoke or beaty which ilTue from it, deftroy the effects of marlb miafmata vipon the human body; hence we find cities more heahhy than country places, and the centre of cities more heal- thy than their fuburbs in the fickly months. To derive the utmoft pofTible benefit from this method of prevent- ing ficknefs, I would advife large fires to be made every evening of brufli between the Ipots from whence the ex- halations are derived, and the dwelling houle, and as near to the latter as is fafe, and not difagreeable. This practice fhould be continued till the appearance of two or three frofts, for frofts as well as heavy rains in the au- tumnal months never fail to put a flop to the progrefs of intermittents. During the fickly feafon, fires fliould be likewife kept in every room in the dwelling houfe, even in thofe cafes where the heat of the weather makes it necefl'ary to keep the doors and windows open. 2. Let me advife my countrymen in fickly fituations, to prefer woolen and cotton to linen clothes in the fum- nier and autumnal months. The mofi: fickly parts of the ifland of jamacia have been rendered more healthy, fince the inhabitants have adopted the ufe of woolen and cotton garments inftead of linen. During the late war, I knew many officers both in the Britifh and American armies who efcaped fevers in the mofi: fickly places, by wearing woolen fliirts, or waift- coats conftantly next to their fkins. I have heard the pre- fent diminution of the human body in ftrength and fize, compared with its ancient vigor and form, afcribed in part to the introdu£tion of linen garments. I am not dlfpofed to controvert this opinion, but I am fure of the efficacy of woolen clothes in wet and cold climates in pre- venting fevers of all kinds. The parliament of Great Britain BILIOUS AND INTERMITTING FEVERS. 211 Britain compels every body that dies within the ifland to be buried in a woolen fliirt or winding fheet. The law would be much wifer if it compelled every body to wear w^oolen garments next to their fkins during life, and linen after death. 3. The diet in the fickly months Ihould be generous. Wine and beer fhould be the drinks of this feafon inftead of fpirits and water. I do not think that fruit and vege- tables of any kind produce fevers, but as the feafon of the year produces languor and weaknefs, a larger quantity of animal food than ufual is befl: calculated to oppofe them. Salted meat for this reafon is preferable to frefh meat. Food of all kinds eaten daring the fickly months fhould be well fcafoned. 4. The evening air fliould be avoided as much as pof- fible. There are at prcfent few places in Pennfylvania where it is fafe to fleep, or even to fet, after the going dovi^n of the fun, in the fickly months, with the windows open. The morning air before the fun rifes, fliould not be breathed, until the body has been fortified with a little folid aliment, or a dnmght of bitters. Thefe bitters fliould be made of centaury, wormwood, camomile, or the bark of the willow or dogwood trees, infufed in tvater. Bitters m.ade with fpirits, or even wine, cannot be taken in a fuflicient quan- tity to do fervice, without producing intoxication, or the deadly habit of loving and drinking fpirituous liquors. 5. Too much cannot be laid in favour of cleanlinefs, as a means of preventing fevers. The body Ihould be bathed or waflied frequently. It has been proved that in the highlands of Jamaica adding fait to water, renders it more powerful in preventing difeafes when applied to the body. Equal pains fliould be taken to promote cleanli- nefs in every fpecies of apparel. OfFal matters, efpecially thofe which are of a vegetable nature, iliould be removed from the neighbourhood of a dwelling houfe. The dung of domeflic animals during its progrefs tov;ards manure 212 ENQUIRY INTO THE CAUSE of may be excepted from this diredlion. Nature, •which made man and thefe animals, equally neceffary to each other's fubfiftence, has kindly prevented any inconveni- ence from their living together. On the contrary, to re- pay the hufbandman for affording a fhelter to thefe ufe- ful and helplefs animals, nature has done more. She has endowed their dung with a power of deftroying the effedls of marlli exhalations, and of preventing fevers. The miferable cottagers in Europe who live under the fame roof, and in fome inftances in the fame room with their cattle, are always healthy. In Philadelphia, fevers are lefs known in the neighbourhood of livery ftables, than in any other part of the city. I could mention a family that has lived near thirty years near a livery liable in a fickly part of the city, that has never known a fever but from the meafles or fmall-pox. N° XXVI. Jn Account of the late Dr. Hugh Martin'j Cancer Poivder, ivith brief Ohfervations on Cancers. By Ben- jamin Rush, M. D. ^'c. (^'c. ReadFebniary A Fgw years ago a Certain Dr. Hugh Mar- _^j^ tin, a furgeon of one of the Pennfylvania regiments ftationed at fort Pitt, during the latter part of the late war, came to this city, and advertifed to cure can- cers with a medicine which he faid he had difcovered in the woods, in the neighbourhood of the garrifon. As Dr. Martin had once been a pupil of mine, I took the li- berty of waiting upon him, and afked him fome queftions refpe£ling his difcovery. His anfvvers were calculated to make me believe, that his medicine was of a vegetable nature, and that it was originally an Indian remedy. He fliewed On Dr. MARTIN's CANCER POWDER. 213 fhewed me fome of the medicine, which appeared to be the powder of a well dried root of fome kind. Anxious to fee the fuccefs of this medicine in cancerous fores, I prevailed upon the dottor to admit me to fee him apply it in two or three cafes. I obferved in fome inftances, he applied a powder to the parts affedted, and in others only touched them with a feather dipped in a liquid which had a white fediment, and which he made me believe was the vegetable root diffufed in water. It gave me great plea- fure to witnefs the efficacy of the dotftor's applications. In feveral cancerous ulcer;'., the cures he performed were complete. Where the cancers were much conneded with the lymphatic fyftem, or accompanied with a fcrophulous habit of body, his medicine always failed, and in fome inftances did evident mifchief. Anxious to difcover a medicine that promifed relief in even a few cafes of cancers, and fuppofmg that all the cauftic vegetables were nearly alike, I applied the Phyto- lacca or poke root, the ftramonium, the arum, and one or two others, to foul ulcers, in hopes of feeing the fame effedls from them which I had feen from Dr. Martin's powder, but in thefe I was difappointed. They gave fome pain, but performed no cures. At length I was furnifh- ed by a gentleman from fort Pitt with a powder which I had no doubt, from a variety of circumftances, was of the fame kind as that ufed by Dr. Martin. I applied it to a fungous ulcer, but without producing the degrees of pain, inflammation, or difcharge, which I had been accuftomed to fee from the application of Dr. Martin's powder. After this, I fliould have fufpedted that the powder was not a fimple root, had not the doctor continued upon all occafi- ons to affure me that it was wholly a vegetable preparation. In the beginning of the year 1784 the dodtor died, and it was generally believed that his medicine had died with him. A few weeks after his death, I procured from Mr. Thomas Lieper, one of his adminiftrators, a few ounces of E e the 214 On Dr. MARTIN's CANCER POWDER. the do£lor's powder, partly with a view of applying it to a cancerous fore which then offered, and partly with a view of examining it more minutely than I had been able to do during the doctor's life. Upon throwing the pow- der, which was of a brown colour, upon a piece of white paper, I perceived diftindlly a number of white particles Scattered through it. 1 fufpeded at firft that they were corrofive fublimate, but the ufual tefts of that metallic fait foon convinced me that I was miftaken. Recolledting that arfenic was the bafis of moft of the celebrated cancer powders that have been ufed in the world, I had recourfe to the tefts for detecting it. Upon fprinkling a fmall quantity of the powder upon fome coals of fire, it emitted the garlic fmell fo perceptibly as to be known by feveral perfons whom I called into the room where I made the experiment, and who knew nothing of the objed of my enquiries. After this with fome difficulty I picked out about three or four grains of the white powder, and bound them between two pieces of copper, which I threw into the fire. After the copper pieces became red hot, I took them out of the fire, and when they had cooled, difcovered an evi- dent whitenefs imparted to both of them. One of the pieces afterwards looked like dull filver. Thefe two tefts have generally been thought fufficient to diftinguifti the prefence of arfenic in any bodies, but I made ufe of a third, which has lately been communicated to the world by Mr. Bergman, and which is fuppofed to be in all cafes infal- lible. I infufed a fmall quantity of the powder in a folution of a vegetable alkali in water for a fe^v hours, and then poured it upon a folution of blue vitriol in water. The colour of the vitriol was immediately changed to a beautiful green, and afterwards precipitated. I iTiall clofe this paper with a few remarks upon this powder, and upon the cure of cancers and foul ulcers of all kinds. The On Dr. MARTIN's CANCER POWDER. 215 I. The ufc of cauftics in cancers and foul ulcers Is very ancient, and univerfal. But I believe arjhiic to be the mofl; efficacious of any that has ever been ufed. It is the bafis of Plunkett's and probably of Guy's well known cancer powders. The great art of applying it fuccefs- fully, is to dilute and mix it in fuch a manner as to mi- tigate the violence of its aftion. Dr. Martin's compofiti- on was happily calculated for this purpofe. It gave lefs pain than the common or lunar cauftic. It excited a mode- rate inflammation, which feparated the morbid from the found parts, and promoted a plentiful afflux of humours to the fore during its application. Itfeldom produced an efcar; hence it infmuated itfelf into the deepeft receffes of the cancers, and frequently feparated thefe fibres in an un- broken ftate which are generally called the roots of the cancer. Upon this account, I think, in an ulcerated can- cer it is to be preferred to the knife. It has no adion up- on the found (kin. This Dr. Hall proved by confining a fmall quantity of it upon his arm for many hours. In thofe cafes where Dr. Martin ufed it to extrad: cance- rous or fchirrous tumors that were not ulcerated, I have reafon to believe that he always broke the fkin with Spa- nifh flies. 2. The arfenic ufed by the dodlor was the pure white arfenic. I fhould fuppofe from the examination I made of the powder with the eye, that the proportion of arfenic to the vegetable powder, could not be more than -^^ part of the whole compound. I have reafon to think that the dodtor employed different vegetable fubfl:ances at diff'erent times. The vegetable matter with which the arfenic was combined in the powder which 1 ufed in my expe- riments, was probably nothing more than the powder of the root and berries of the folanum lethale, or deadly nightfhade. As the principal, and perhaps the only de- fign of the vegetable addition was to blunt the acti- vity of the arfenic, I fliould fuppofe that the fame propor- E e a tion 2i6 On Dr. MARTIN 's CANCER POWDER. tlon of common wheat flour as the dodtor ufed of his cauflic vegetables, would anfwer nearly the fame purpofe. In thofe cafes where the dodlor applied a feather dipped in a liquid to the fore of his patient, I have no doubt but his phial contained nothing but a weak folution of arfenic in water. This is no new method of applying arfenic to foul ulcers. Dr. Way of Wilmington, has fpoken in the higheft terms to me of a wafh for foulnefl'es on the fkin, as well as old ulcers, prepared by boiling an ounce of white arfenic in two quarts of water to three pints, and apply- ing it once or twice a day. 3. I mentioned formerly that Dr. Martin was often unfuccefsful in the application of his powder. This was occafioned by his ufing it indifcriminately in all cafes. In fchirrous and cancerous tumours, the knife {hould always be preferred to the cauftic. In cancerous ulcers attended with a fcrophulous or a bad habit of body, fuch particularly as have their feat in the neck, in the breafts of females, and in the axillary glands, it can only protradl the pati- ent's mifery. Moft of the cancerous fores cured by Dr. Martin were feated on the nofe, or cheeks, or upon the fur- face or extremities of the body. It remains yet to difcover a ciu"e for cancers that taint the fluids, or infedt the whole lymphatic fyftem. This cure I apprehend muft be fought for in diet, or in the long ufe of fome internal medicine. To pronounce a difeafe incurable, is often to render it fo. The intermitting fever, if left to itfelf, would proba- bly prove frequently, and perhaps more fpeedily fatal than cancers. And as cancerous tumours and fores are often negledted, or treated improperly by injudicious people, from an apprehenfion that they are incurable, (to which the frequent advice of phyficians " to let them alone," has no- doubt contributed) perhaps the introduction of arfenic into regular praftice as a remedy for cancers, may invite to a more early applicationto phyficians, and thereby pre- vent On Dr. MARTIN's CANCER POWDER. 217 vent the deplorable cafes that have been mentioned, which are often rendered fo by delay or iinflcilful management. 4. It is not in cancerous fores only that Dr. Martin's powder has been found to do fervice. In fores of all kinds, and from a variety of caufes, where they have been attend- ed with fungous flefh or callous edges, i have ufed the dodlor's powder with advantage. I flatter myfelf that I fhall be excufed in giving this detail of a quack medicine, when the fociety retiedl that it was from the inventions and temerity of quacks, that phy- ficians have derived fome of their mofl active and ufeful medicines. N° XXVII. llluftrlflimx ac celeberrlmre Societati Scientiarum quoe eft Philadelphia:. S. P. D. Christianus Mayer Ser"" Eledoris Palatini Aftronomus. CRIBENDI occafionem a CI. D. Ferdinando Far- mer oblatam eo minus negligendam putavi quod hac ratione aliquantum refpondeam honori, quo me illuftrifTima focietas afFecit, cum me in album fuorum fociorum ad fcripfit. Ex libro Philadelphia: imprelfo & ad me tribus circiter abhinc annis tranfmilTo intellexi non line magno animi mei fenfu, etiam Philadelphia; excoli aftronomiam. Libro illo fcriptifque meis aftronomicis infelici incendio abhinc biennio conlumtis, de novis mels quibufdam in coelo inventis ad focietatem illuftriflimam allquid fcribendum efle, duxi. Speculam novam ad omnes ufus accommoda- tam^ ^i8 MAYERI OBSERVATIONES ASTRONOMIC^. tarn Manhemii inhabito ; nee defunt pretiofiffima Londi- nenfia inftrumenta, in quibus prsecipue eminet quadrans muralis aeneus 8 pedum in rhadio a eel. artlfici Bird anno 1 775 confeftus & plane infigni tubo achromatico inftrue- tus, folidiffimeque muro affixus ad plagam coeli meridio- nalem, quo inftrumento, quoties coelum favet, utor quo- tidie. Adverti autem ftatim abhine biennio in ftellis fixis plane multis a primo gradu magnitudnis ad fextum ufque, diftingui alias ftellulas parvulas comites, quarum alice ob lucem tranquillam & obtufam planetarumfpeciemreferunt, alix telefeopicam parvitatem non excedunt. Quod maxime mirabar, illud eft, quod has ftellulas comites, pauciflimis duntaxat exeeptis, nullo noto eatalogo contineri viderem, cum tamen earum ufum ad determinandum motum pro- prium fixarum efle plane infignem evidenter colligerem. Cum enim ibi, ubi paucorum plerumqe fecundorum repe- ritur diff^erentiaafcenfionis redtjE&declinationis inter fixam lucidiorem, ejufque comitem, lapfus temporis baud aliam variationem ftellge fixse, quam ejus eomiti inducere poftit, unde demum eunque ifta mutatio oriatur, five a prxceffi- one cequinoftiorum, five a variatione obliquitatis eclipticse, five a deviatione inftrumenti, feu ab aberratione luminis aut nutationis, five ab alia quaeunque caufa, quae pendeat a mutabili ftatu atmofpherae aut locorum latitudine, con- tingit fane, ut omnis mutatio vifa inter fixam, ejufque comitem, motusproprii argumentum praebeat certiftimum, five is fixam five ejus comitem afficiat. Noveram Halleum eel. Angliae aftronomum primum fuifle, qui anno 1 719 ex inftituta comparatione obfervationum Flamfteadii cum illis Ptolomcci in paucis quibufdam fixis, Syrio, Ar£luro & Aldebaran deprehendit has ftellas moveri motu fingulari proprio. Sed fimul noveram in Hiftoria Coelefti Brittan- nica Flamfteadii jam anno 1690 ufurpatam fuifle a Flam- fteadio vocem comitis fixarum, cum vir fummus nee dum de motu proprio fixarum eogitaflet. Aftronomi reliqui Halleo pofteriores quotquot in motum proprium fixarum inquifiverunt, MAYERI OBSERVATTONES ASTRONOMICi^. 219. inquifiverunt, Hallei methodum fecuti funt, comparando obi'ervatlones fuas cum obfervationlbus antiquorum : me- thodus hscc prolixos requirit calculorum labores, multlfque dubitationibus manet obnoxia ob incertitudintm, lubricam- que conditionem inftrumentorum, & obfervationum anti- quarum ; non item methodus mea nova, qua ex variatione inter comitem & fixam illuftriorera obfervata, ftatim con- fequitur dari motum proprium, vel utriufque vel allerutrius fideris. Itaque ducentos fere diverfarum fixarum comites a biennio obfervavi, eundem fere paralellum ftatim ante vel poft fixam dccurrentes, & obfervationes hujufmodi plures cum. eel. Angliae aftronomo Nevil Maflcelyne com- municavi, qui eas fibi gratiffimas accidifle refpondet. Ex multis, obfervationes paucas ad illuftriflimam focietatem fpeciminis loco tranfmitto, quarum refpondentes in Hifto- ria Ccelefti Britannica Flamfteadii invenio, unde fimul patet, quam obfervationes hujufmodi pra^clare ferviant motui proprio detegendo. Prima et fecunda columna finiftlma tabula: fequentis ex titulo facillime intelligitur. Tertia columna differentiam A. R, in tempore medio in- dicat Inter ftellam ejufque comitem : cornes prscedens fixam, primo loco in tabula fcribitur, comes fequens poft fixam ponitur. Quarta columna differentiam declinationis inter fixam ejufque comitem notat, qaalem ego Manhemii obfervavi. Litera A fignificat comitem elfe auftraliorem, litera B magls borealem. Sequentes columns, obfervationes ejufdem ftellce fadas a Flamfteadio, continent. 2 20 MAYERI OBSERVATIONES ASTRONOMICiE. JV1av.:r, Manhdim. FLAMb rAtu, Orcenwicu. j Nomina Fixarum. Diff. A. R. in tempore. Differ. Declina. Diff. A. R. Differ. Declina. 1777 Die 28 Feb. j) Leonis Comes 7ae. five 8va;. 2'. 15". 38'.58".6.A 2'. 18". 38'. 50". A 1690 Die 25 Mar. 1777 28 Feb. item 23 Feb. Com. V Leonis 6ts. V Leonis 4tK 5". 2I'.57".2.A 2". 22'. S"- 1691 6 Aprilis. 1777 4 Aprilia. Comes ■J" Leonis I'. 5". 8'. 0". 15. B 56. 8'. 30". B 1690 25 Martii. 1777 11 Martii. Propus Comes jtx J'. 36". 7'. 30." 5'- 3S". 7'. 0". 1690 7 Feb. 1777 8 Martii. Procyon Comes 11. 8v« I'- 4C/'- 5- 3'. 6". 2. A I'. 34". 4'. 40". A 169I 4 Oifto. 1777 13 Nov. Com. 7mje I Pifcium 51". 2'. 5 7". I. B 47"- 2'. 30". B 1700 Nov. 13. 1777 Aprilis 6. Comes n Cancri 2'. 49"- I'. 40". B 2'. 44". I'. 12". B 1690 Feb. 1 8. 1777 Aprilis 8. Com. yx /3 Leonis 30". i8'.27".i.A 33"! 1692 Aprilis 24. 1776 'Arfturus Mai. 18. Comes. 0. 0. 6". °- »3- 37- 3 Com. 0. 5". Ar(iluru5. 0. 26. 30. 1690 Febru. 14. 1777 Mart. II. 1776 Mai. 18. 1777 Aprilis I. Procyon Comes 7s. Arflurus Comes. Cancri fcg. n Cancri 6. 39"- 0. 0. 6. 14'. 56". 3'. 8". 1. A 0- i3- 37-4 -,2. 29. 6. B 35". 1692 22 Janu. Maskelvne. A. R. 1 0.0.4. o.23'.58".8. ij. I. 32. 25. B 1765 20 Mai. 1691 10 Mnrtii. Apparet ex omnibus Ardlurum omnium celerrime ferri motu proprio in occafum, fequidem idem comes, qui tempore Flamfteadii 1690, die 14 Februarii Ardurum prsecedebat 5" in tempore nunc 6" poft Ardturum meridi- anum ingreditur : ex imminuta quoque differentia decll- nationis inter Ardlurum ejufque comitem, patet, Ardturum motu proprio quotannis fere 2" in circulo moveri verfus auftrum. Id ex eo perfpicuum eft, quod declinatio a me obfervata comitis redudla ad parallelum grenovicenfem eandem producat altitudinem poli grenovicenfis, qualis ex obfervatione Flamfteadii eruitur, non item declinatio hodie obfervata Ardturi etiam aberratione & nutatione corredta. Similis indagatio fieri poteft in reliquis fixis, earumque comitibus, atque ex inftituta comparatione cum aliis fixis deprehendi MAYERI OBSERVATIONES ASTRONOMICiE. 221 deprehendi poteft, num fixae an comiti vel utrique motus proprius tribuendis fit. Obfervationes omnes in piano meridiani quadrante mu- rali fadtae funt Manhemii in nova fpecula a me xdificata S. Ele£loris Palatini : ejus longitudo ad ortum Grenovicii eft fere 34' 6" in tempore, latitudo fere 49° 27' 50" Gaudebo maxime fi has meas obfervationes illuftriflimx focietati baud ingratas accidifle intellexero, cujus benevo- lentise me demififfime commendo. Illuftriflimx ac celeberrimse Societati, Cuetor et fervus perpetuus, CHRISTIANUS MAYER, Sereniffimi Eledtoris Palatini et Ducis Bavarise Aftronomus. Manhemii in Germania,') die 24 Aprilis 1778. 5 (Translation.) To the illuftrious and celebrated Society of Sciences at Philadelphia, Christian Mayer, Aftronomer to his Serene High- nefs the Eledlor Palatine, Wifheth Profperity. I THOUGHT it my duty to embrace the opportunity which my good friend the Rev. Mr. Ferdinand Farmer has procured me of writing to your illuftrious fociety, that I may make fome return to the honour which you have done me by electing and enrolling me among your mem- bers. It gave me a very fenfible pleafure to find, by the printed volume of tranfadions, which you fent me about three years ago, that the fcience of aftronomy was culti- vated even at Philadelphia. That volume of yours, to- F f gether 222 ASTRONOMICAL OBSERVATIONS. gether with my own aftronomical papers, having been unhappily deftroyed by fire about two years ago, I have refolved to give your illuftrious focicty fome fhort account of certain new celeftial difcoveries which I had made. My refidence is now at Manheim, in a new obfervatory, fitted for every aflronomical purpofe ; and Vv'ell furnifhed with the moft precious and accurate inftruments made at London ; amongft which the chief is a brafs mural qua- drant of eight feet radius, the workmanfhip of that cele- brated artift Mr. Bird, finifhed in the year 1775, fitted with an achromatic telefcope, and fixed to a folid wall to- wards the meridian. With this inftrument I make daily oblervations of the heavens, when the weather will per- mit, and two years ago I diftinftly difcovered, among many of \hzjixedjiars (from the firjl to 'Cas.fixth magni- tude) other concomitant or attendant little Jiars ; fome of which, from their mild, faint (or unfparkling) light, have the appearance of planets, while others. of them have the appearance of telefcopic ftars, in refpedl to their fmallnefs. But what furprifed me moft was, that none of thefe attendant little ftars, a few perhaps excepted, have ever been noted in any catalogue which I have fecn ; although I could clearly colledt the fingular ul'e which may be made of them for afcertaining and determining the proper mo- tion of the fixed ftars, as it is called. When the difference of right afcenfion and declination between two ftars is at moft but a few feconds, any variation arifing from the preceflion of the equinoxes, the variation of the obliquity of the ecliptic, the deviation of the inftrument, the aber- ration of light or the nutation, or from any other caufe depending on the mutable ftate of the air or latitude of places, muft aff"e£t them both equally. Therefore when after any length of time a greater variation of right afcen- fion or declination is found in one of fuch ftars than in the other, it aff"ords a certain argument of the proper motion of one or the other, whether that change affe(Ss the fixed flar or its attendant. I know ASTRONOMICAL OBSERVATIONS. 223 I know that the celebrated Englifh aftronomer Halley, was the firft who, about the year i 719, by a careful com- parifon of the obfervations of Flamitead with thofe of Ptolemy, refpedling a few fixed ftars, viz. Sirius, Ardturus and Aldebaran, difcovered that thefe ftars had a proper motion of their own. But I likewifc know, that in Flam- Head's Britifli celeftial hiftory the word concomitant or at- tendant of fixed Jlars is made ufe of, when that great man had not even thought of a proper motion of the fixed ftars. The other aftronomers, pofterior to Halley, as far as they inveftigated the proper motion of \.\\e fixed fiars., fol- lowed the Italian method of comparing their own obfer- vations with thofe of the ancients. This method requires the labour of prolix calculation, and remains liable to doubts and uncertainty, on account of the inaccuracy of ancient inftruments and obfervations. My new method is not liable to fuch objections, becaufe from the obferved variation of the attendant ftar and the brighter fixed ftar, it immediately follows that there is a proper motion giv- en, either of the one or the other. I have, therefore, in the fpace of two years, obferved almoft two hundred attendants of diff'erent fixed ftars, running almoft the fame parallel, immediately before or after the fixed ftar ; and have communicated many of fuch obfervations to the celebrated Englifli aftronomer Nevil Maflcelyne, who has exprefled his high fatisfadlion therewith. Out of many obfervations, I fend your illuftrious foci- ety a few by way of fpecimen, being fuch whereof I find correfpondent obfervations in the Flamfteadian celeftial hiftory ; whence it appears at once how excellently ob- fervations of this kind ferve for difcovering the proper mo- tion of fuch ftars. The firft and fecond column of the following table next to the left hand is eafily underftood from its title. The third column fhews the difference of A. R. in mean time F f 2 between 2 24 ASTRONOMICAL OBSERVATIONS, between the attendant and^^r. The attendant which pre- cedes the fixed ilar occupies the firll place in the table. The fubfequent attendant is placed after the fixed ftar. The fourth column fhews the difference of declination be- tween the fixed ftar and attendant. The letter A, fignifies that the attendant is more fouth, B, that it is more north than the ftar. The fubfequent columns contain Flam- ftead's obfervations of the fame fixed ftars. The table. Ky Maver, at Manheim. By Flamstead, at Cireeuvvich. | rime of Ob- fervation. Names of Star. Diff. A. R. in time. Differ. ofDecUna. Diff. A. R. in time. Differ, of Declina. Time of Ob- fervation. 1777 Februar. 28. f Leonis attendant 7m. 2'. 15"- 38'.58".6.A 2'. 18". 38'. 50". A 1690 March 25. 1777 Feb. 25, 28. Attend. 6m. y Leonis 4m. J". 2l'.57".2.A a". 22'. S". 1691 6 April. 1777 April 4. Attendant, T Leonis I'. 5". 8'. 0". 15. B 56. 8'. 30". B 1690 25 March. 1777 March 11. Propus attendant jm. 5'. 36". 7'. 30." 5'- 38"- 7'. 0". 1690 7 Feb. 1777 March 8. Procyon attendant 8m. I'. 40". 5- 3'. 6". 2. A I'. 34". 4'. 40". A 1691 4oao. 1777 13 Nov. Attendant 7m. i Pifcium 51"- 2'.J7". I.B 47". 2'. 30". B 1700 Nov. 13. 1777 April 6. Attendant, n Cancri a'. 49". I'. 40". B 2'. 44". I'. 12". B 1690 Feb. 18. I7'^7 April 8. Attendant 7m. /S Leonis 30". l8'.27".l.A Zf\ l6yi April 24. 1776 Arifturus May 18. Attendant, 0. 0. 6". 0. 23. 37. 3 .Com. 0. 5". Arifturus. 0. 26. 30. 1690 Febru. 14. 1777 Procyon March II. Attendant 7m. 39"- 0. 0. 6. 14'. 56". 3'. 8". I. A 0. 23. 37. 4 ;,2. 29. 6. B 3.5". 1692 22 Janu. 1776 May 18. 1777 April I. AriSlurus Attendant, Cancri n Cancri 6m. Maskelvne. A. R. 0.0.4. o.23'.58".8. 15. I. 32. 2J. B 1765 ;o May. 1691 in March. It appears from every obfervation, that of all the ftars, Ardturus, by his proper motion, is carried with the great- eft celerity weftward ; fince the fame attendant, which in Elamftead's \ ASTRONOMICAL OBSERVATIONS. 2-2.f Flamftead's time, 1690, February 14, preceded Ar£lurus 5" in time, now comes to the meridian 6" after him. Likewife from the very fmall difference of declination be- tween Ar£lurus and his attendant, it appears that Ardiu- rus by his proper motion moves almoft 2" foutherly every year in a circle. N° XXVIII. Obfefuations on the Caiife and Cure of the Tetanust by Benjamin Rush, M. D. Profejfor of Chemiftry in the Univerftty of Pennfyl'uania. ReadMar. g ^ U R I N G my attcndancc upon the military 17. 1786. ^^ hofpitals of the United States, in the courfe of the late war, I met with feveral cafes of the Tetanus. I had frequently met with this diforder in private pradlice, and am forry to fay that I never fucceeded with the ordinary re- medy of opium in any one cafe that came under my care. I found it equally ineffectual in the army. Baffled in my ex- pe(5tations from a remedy that had been fo much celebrated, I began to inveftigate more particularly the nature of the diforder. I found it to be a diforder of warm climates, and warm feafons. This led me to afcribe it to relaxation. I refolved to attempt the cure of it by a fet of medicines in fome meafure the oppofites of moft of the medicines that had been employed in that diforder. Soon after I adopt- ed this refolution, I was called to vifit Col. John Stone, ■who was wounded through the foot at the battle of Ger- mantown on the 4th of Odtober 1777. -^^ ^'^^ '" ^^ third day of a Tetanus, His fpafms were violent and his pains fo exquifite that his cries were heard near a hun- dred yards from his quarters. His head was thrown a little backwards, and his jaw had become fliff and contradled.. He 226 OBSERVATIONS on the TETANUS. He was under the care of a fkilful regimental furgeon who was pouring down opium in large quantities with- out effedt. Duty and friendftiip both led me to do my utmoft to fave the life of this valuable officer. I immediately difmifled the opium, and gave him large quantities of wine and bark, to the amount of two or three ounces of the latter, and from a bottle to three pints of the former in the day. In a few hours I was delighted with their effedls. His fpafms and pains were lefs frequent and violent, and he flept for feveral hours, which he had not done for feveral days and nights before. With the fame indication in view, I applied a blifter be- tween his fhoulders, and rubbed in two or three ounces of mercurial ointment upon theoutfide of his throat. He continued to mend gradually under the operation of thefe medicines, fo that in ten days he was out of danger, al- though the fpafm continued in his wounded foot for feve- ral weeks afterwards. In the fummer of the year 1782 I was called to vifit a fervant girl of Mr. Alexander Todd, merchant of this city, who had brought on a Teta- nus by fleeping in the evening on a damp brick pave- ment, after a day in which the mercury in Farenheit's thermometer had flood at near 90°. The cafe was near- ly as violent and alarming as the one I have defcribed. I treated her in the fame manner, and with the fame fuc- cefs. To the above named medicines, 1 added only the oil of amber which fhe took in large dofes, after I fuf- pedl:ed the tonic powers of the bark and wine began to loofe their effedls. The good effedts of the oil were very obvious. She recovered gradually and has continued ever fmce in good health. In the fummer of the fame year I was called to Alexander Leflie, a joiner, who had run a nail in his foot. I found him the day afterv/ards in ex- treme pain, with fmall convulfions and now and then a twinge in his jaw. The wound in his foot was without fwelling OBSERVATIONS on the TETANUS. 227 fwclling or inflammation. I dilated the wound and filled it with lint moiftcned with fpirit of turpentine. This in a little while produced a good deal of pain and a great inflam- mation in his foot. While I was preparing to treat him in the manner I had treated the two former cafes, the pains and fpafms in his body fuddenly left him, and in twenty- four hours after I faw him, he complained of nothing but of the pain and fwelling in his foot, which continued for feveral weeks and did not leave him till it ended in a fup- puration. From the hifl:ory of thefe three cafes, I beg leave to make the following remarks. 1. That the prcdifpofition to the Tetanus depends upon relaxation. This relaxation is generally produced by heat; but exceflive labour, watchings, marches, or fatigue from any caufe, all produce it llkewife, and hence we find it more frequent from wounds received in battles, than from fimi- lar wounds received in any other way. Thefe wounds more certainly produce the Tetanus, if they have been preceded for fome time with warm weather. Dr. Shoepft, the phyfician general of the Anfpach troops that ferved at the fiege of York in the year 1 78 1, informed me of a fin- gular fail upon this fubjecS. Upon converfing with the French lurgeons after the capitulation, he was informed by them that the troops who arrived juft before the fiege from the Weft-Indies with Count de Graife, were the only troops belonging to their nation that fuff'ered from the Tetanus. There was not a fingle inftance of that difor- der among the troops who had fpent a winter in Rhode- Ifland. 2. As the Tetanus feems to be occafioned by relaxati- on, th"? medicines indicated to cure it are fuch only as are calculated to remove this relaxation and to reftore a tone to the fyftem. The bark and wine appear to adl in this way. The operation of the blifters is of a more complicated na- ture. That they are fedative and antifpafmodic in fevers is univerfally acknowledged, but in the peculiar ftate of irritability 228 OBSERVATIONS on the TETANUS. irritability which occurs in the Tetanus, perhaps their ef- fe£ls are more fimply ftimulating. But I will go one flep further. In order to cure this diforder, it is neceflary not only to produce an ordinary tone in the fyflem, but fomething like the inflammatory diathefis. The abfence of this diathefis is taken notice of by all authors, particularly by Dr. Cullen*. Mercury appears to adl only by promoting this diathefis. Hence it never does any fervice unlefs it be given time enough to produce a falivation. The irritation and in- flammation produced in the mouth and throat, feldom fail to produce the inflammatory diathefis, as blood drawn in a ialivation has repeatedly fhewn. I apprehend that the oil of amber adis as a fl;imulant chiefly in this diforder. I have heard of a Tetanus being cured in the ifland of Grenada by large dofes of muftard. Dr. Wright, lately of the ifland of Jamaica, relates in the 6th volume of the London Medical Eflays, feveral remark- able cafes of the Tetanus being cured by the cold bath. Both thefe remedies certainly a£t as ftimulants and tonics. By reafoning a priori, I conceive that electricity would be found to be an equally powerful remedy in this diforder. As a general inflammatory diathefis difpofes to topical inflammation, fo topical inflammation difpofes to general inflammatory diathefis. Wounds upon this account are lefs apt to inflame in fummer than in winter. In the Te- tanus I have uniformly obferved an abfence of all inflam- mation in the wounds or injuries that produced it. A fplinter under the nail produces no convulfions, if pain, inflammation and fuppuration follow the accident. It is by exciting pain and inflammation I apprehend that the fpirit of turpentine ads in all wounds and punctures of nervous and tendinous parts. I have never known a fingle inftance of a Tetanus from a wound, where this remedy had been applied in time. It was to excite an inflamma- tion in the foot of Mr. Leflie, that I dilated the wound and * Firft Lines, Vol. IIL OBSERVATIONS on the TETANUS. 229 and filled it with the fpirit of turpentine. I was not fur- priled at its good effeds in this cafe, for I was prepared to expcdl them. I find a remarkable cafe related in Dr. W. Monroe's Thefis, publilhed in Edinburgh in the year 1783, of a black girl who had a Tetanus from running a nail in her foot, being perfeftly cured by deep andextenfive incifions being made in the wounded part by Dr. John Bell, of the ifland of Grenada. It is by producing inflammation in a particular part, and tone in the whole fyftem, I apprehend that the am- putation of a wounded limb fometimes cures a Tetanus ; and it is becaufe the degrees of both are too inconfiderable to oppofe the violence of the fpafins in the advanced ftages of the Tetanus, that amputation often fails of fuccefs. I have been informed by a phyfician who refided fome time at St. Croix, that the negroes on that ifland always apply a plaifter made of equal parts of fait and tallow to their "freih wounds, in order to prevent a locked jaw. The fait always produces fome degree of inflammation. If the fails that have been ftated are true, and the in- ferences that have been drawn from them are jufl:, how fliall we account for the adion of opium in curing this diforder ? I do not deny its good eftedts in many cafes, but I believe it has failed in four cafes out of five in the hands of moft practitioners. It is remarkable that it fucceeds only where it is given in very large dofes. In thefe cafes I would fuppofe that its fedative powers are loft in its fli- mulating. It is upon a footing, therefore, in one refpedl, with the ftimulating medicines that have been mentioned; but from its being combined with a fedative quality, it is probably inferior to moft of them. I am the more inclin- ed to adopt this opinion, from an account I once received from Dr. Robert, of the ifland of Dominique, who in- formed me that after having cured a negro man of a Te- tanus with large dofes of opium, he was afterwards feized G g with ^3,o OBSERVATIONS on the TETANUS. with a diforder in his flomach, of which he died in a few days. Upon opening him, he found his ftomach inflam- ed and mortified. I do not forhid the ufe of opium alto- gether in this diforder. I think fmall dofes of it may be given to eafe pain, as in other fpafmodic diforders ; but as its qualities are complicated, and its efficacy doubtful, I think it ought to yield to more fimple and more powerful remedies. To the cafes that have been mentioned, I could add many others, in which I have reafon to believe that the excitement of a topical inflammation by artificial means, has eff"e£lually prevented a Tetanus. To this account of the Tetanus, I beg leave to fubjoin a few words upon a diforder commonly called the jaw-fall in infants, or the Trifmus Nafcentium of Dr. CuUen, which is nothing but a fpecies of Tetanus. I have met with three cafes of it in this city, all of which proved fatal. The ftage of the diforder in which I was confulted, and the age and weaknefs of the infants, forbad me to attempt any thing for their relief. I have introduced the fubje£l of this diforder in children, only for the fake of mentioning a fadl communicated to me by the late Dr. Cadwalader Evans of this city. This gentle- man praQiifed phylic for feveral years in Jamaica, where he had frequent opportunities of feeing the Tetanus in the black children. He found it in every cafe to be in- curable. He fuppofed it to be occafioned by the retention of the meconium in the bowels. This led him mvaria- bly to purge every child that was born upon the eftates committed to his care. After he adopted this practice, he never met with a fingle inflance of the Tetanus among children. Perhaps it may tend to enlarge our ideas of the Teta- nus, and to promote a fpirit of enquiry and experiment, to add, that this diforder is not confined to the human fpecies. I have known feveral inftances of it in horfes from nails running OBSERVATIONS on the TETANUS. 231 running in their feet, and other accidents. It is attended with a rigidity of the mufcles of the neck, a ftiffnefs ia the limbs, and fuch a contradion of the jaw as to pre- vent their eating. It is generally fatal. In two cafes I had the pleafure of feeing the difcafe perfedly cured by applying a potential cauftic to the neck under the mane, by large dofes of oil of amber, and by plunging one of them into the river, and throwing buckets of cold water upon the other. How far the reafonings contained in this paper may apply to the hydrophobia, I cannot determine, having had no opportunity of feeing the difeafe fince I adopted thefe principles ; but from the fpafmodic nature of the diforder, from the feafon of the year in which it generally occurs, and above all, from the cafe related by Dr. Fothergill, of a young woman having efcaped the effedls of the bite of a mad cat by means of the wound being kept open, (which from its feverity was probably connected with fome degrees of inflammation) is it not probable that the fame remedies, which have been ufed with fuccefs in the Tetanus, may be ufed with advantage in the hydrophobia? — In a difeafe lo deplorable, and hitherto fo unfuccefsfuUy treated, even a conjediure may lead to ufeful experiments and enquiries. N° XXIX. To His Excellency Benjamin Franklin, Efq. L. L. D. ■ Prejident of the State of Pennfyl'uania^ and of the Ame~ rican Phtlofophical Society ■, <^'c, S I R, Philadelphia, January 12, 1786. ^Tf ^86* nPHE fubjed of fmoky chimneys, of which J_ I had the honor of converfing with you at your own houfe laft evening, is of fo much importance to G g a every 232 LETTER CONCERNING every individual, as well as to every private family, that too much light cannot be thrown upon il. A fmoky houfe and a fcolding wife, Are (faid to be) two of the greateft ills in life. And however difficult it may be to remedy one of thofe ills, yet any advances we may be able to make towards removing the inconvenicncies arifmgfrom the other, can- not fail to be favourably received by the public. As they are fhortly to be favoured with your fentiments on that fiibjeft, poffibly the following obfervations, which were in fa£l occaiioned by neceffity, and are the refult of my 'own experience, may not be altogether undeferving of notice. When I left London and went to live in Devonfhire in the latter end of the year 1777, it happened to be my lot to dwell in an old manfion which had been recently mo- dernifed, and had undergone a thorough repair. But as in moft of the old houles in England, the chimneys, which were perhaps originally built for the purpofe of burning wood, though they had been contraded in front, fmce coal fires came into general ufe, to the modern fize, yet they were ftill, above, out of fight, extravagantly large. This method of building chimneys may perhaps have anfwered well enough while it was the cuftom to fit with the doors and windows open; but when the cuftoms and manners of the people began to be more polifl\ed and refined, when building and archite£lure were improved, and they began to conceive the idea of making their chambers clofe, warm, and comfortable, thefe chimneys were found to fmoke abominably, for want of a fufficient fupply of air. This was exactly the cafe with the houfe in which I firfi: lived, near Exeter, and I was under the neceffity of trying every expedient I could think of to make it habitable. The firft thing 1 tried, was that method of contracting the chimneys by means of earthen pots, much in uie in England, J. CHIMNEYS. . 23J England, which are made on purpofe, and which are put upon the tops of them ; but this method by no means an- fwered. I then thought of contrading them below, but as the method of contradting them in front to the fize of a fmall coal-fire grate has an unfightly appearance, as it makes a difagreeable blowing like a furnace, and as it is the occafion of confuming a great deal of unneceffary fuel, the heat of which is immediately hurried up the chimney, I rejecSted this method, and determined to con- trad: them above, a little out of fight. For this purpofe I threw an arch acrofs, and alfo drew them in at the fides. This had fome effedl, but as this contratftion w^as made rather fuddenly, and the fmoke, by flriking againft the corners that were thereby occafioned, was apt to recoil, by v,hich means fome part of it was thrown out into the room ; I determined to make the contraction more gra- dually, and therefore run it up at the back, where the depth of the chimney would admit of it, and alfo {helving or Hoping in a conical kind of direQion at the fides, as high as a man, Handing upright, could conveniently reach, and by this means brought the cavity within the ipace of about twelve by fourteen or fixteen inches, which I found fufficiently large to adm.it a boy to go up and down to fweep the chimnies. This me:hod I found to fucceed per- feflly well, as to curing the chimneys of fmoking, and it had this good efTedl of making the rooms confiderably warmer ; and as this experiment fucceeded fo well, fince the only ufe of a chimney is to convey away the fmoke, I determined to carry it ftill farther, in order to afcertain with precifion, how much fpace is abfolutely neceffary for that purpofe, becaufe all the reft that is fliut up, muft be fo much gained in warmth. Accordingly I laid a piece , of flatc acrofs the remaining aperture, removable at plea— fare, fo as to contract the fpace above two thirds, leaving about three inches by twelve remaining open ; but this fpace, except when the fire burnt remarkably clear, was fcarcely 234 LETTER concerning fcarcely fufEcient to carry away the fmoke. I therefore enlarged it to half the Ipace, that is, to about fix by feven or eight inches, which I found fully fufficient to carry away the fmoke from the largeft fires. When I removed into the Bedford Circus in Exeter, though the houfe was modern, and almoft perfedly new, yet the chimneys were large ; in confequence of which al- moft every room of it fmoked. My predeceflbr, who was the firft inhabitant, had been at great expence in patent ftoves, &c. but without effed: ; but by adopting the me- thod I have juft now defcribed, I not only cured every chimney of finoking, but my houfe was remarked for be- ing one of the warmeft and moft comfortable to live in of any in that large and opulent city. The houfe 1 now live in, in Philadelphia, I am told, has always had the character of being both cold and fmoky ; and I was convinced, as foon as I faw the rooms and examined the chimneys, that it deferved that charac- ter ; for though the rooms were clofe, the chimneys were large : And we fhall ever find, that if our chimneys are large, our rooms will be cold even though they fhould be tolerably clofe and tight ; becaufe the conftant rufhing in of the cold air at the cracks and crevices, and alio at €very opening of the door will be fufficient to chill the air, as taft as it is heated, or to force the heated air up the chimney; but by contracting the chimneys I have cured it of both thefe defedts. There was one remarkable cir- cumftance attending the contradion of the chimney in the front parlour, which deferves to be attended to ; ■which was, that before I applied the caft iron plate, which I made ufe of inftead of flate, to diminifh the fpace requi- fite for a chimney fweeper's boy to go up and down, the fudion or draught of air was fo great, that it was with difficulty I could fhut the door of the room, infomuch that I at firft thought it was owing to a tightnefs of the hinges, which 1 imagined muft be remedied, but upon applying the CHIMNEYS. ^35 the iron plate, by which the fpace was diminifhed one half, the door ihut to with the greateft eafe. This ex- traordinary prefTure of the air upon the door of the room, or fudtion of the chimney, I take to be owing in fome meafure to the unufual height of the houfe. Upon the whole, therefore, this fa£l feems clearly af- certained, viz. That the flue or fize of the chimney, ought always to be proportioned to the tightnefs and clofe- nefs of the room, fome air is undoubtedly neceflary to be admitted into the room in order to carry up the fmoke, otherwife as you juftly obferved we might as well expert I'moke to arife out of an exhaufted receiver; but if the flue is very large, and the room is tight, either the fmoke will not afcend, in confequence of which will be, that the air of your room will be fo frequently and fo conftantly changed that as faft as it is heated, it will be hurried away, with the fmoke, up the chimney, and of courfe your room will be conftantly cold. One great advantage attending this method of curing fmoky chimneys is, that, in the firft place, it makes no aukvvard or unfightly appearance, nothing being to be feen but what is ufual to chimneys in common; and in the fecond place that it is attended with very little ex- pence, a few bricks and mortar with a plate or covering to the aperture, and a little labour, being all that is requi- fite. But in this new country where crops of houfes may be expected to rife almoft as quick as fields of corn, when the principles upon which chimneys ought to be thorough- ly underftood, it is to be hoped, that not only this ex- pence, fmall as it is, but that all the other inconveniencies we have been fpeaking of, will be avoided, by conftrucf^- ing the flues of the chimneys fufliciently fmall. From your humble fervant,. TFIOMAS RUSTON.. I ^3(^ ] N° XXX. Obfervations on the annual Pajfage of Herrings^ by Mr. John Gilpin. AS this very ufeful part of the finny race has nevef been found in the frefh rivers, or waters of Eu- rope, it remains a query amongft the naturahfts, where they go to fpawn and perpetuate their fpecies. I appre- hend this query may be anfwered to the fatisfaftion of the curious by an account of their annual progrefs, from which it will appear they are a fifh of paffage, and ob- ferve one regular annual rout in the fea, fhifting their climate with the fun, and that it is the fame fcoole which is found at different times about Britain and in America. This opinion is founded on obfervations made on feeing them caught at Whitehaven and in this country, from which I have not obferved that there is any vifible differ- ence in the fifh in the different -places, except that thofe at Whitehaven are fatter and rounder than thofe in America ; but this difference is not fo great as that be- tween the fpring and fall mackarel, and which I conceive might be accounted for from the time of the year, and manner in which they appear on each coafl. For they are found on the other fide the Atlantic, or rather in the North fea, in the favourable month of June about the iflands of Shetland, from whence they proceed down to the Ork- neys, and then dividing, they furround the iflands of Great-Britain and Ireland, and unite again off the Land's End in the Britifh channel in September, from whence this grand united fcoole fleers fouth-wefl, and is not found any more on that fide or in the Atlantic, until the fame time the enfiiing year, but appear next on the American coafls. Of herrings. '■^7 coafts. They arrive in Georgia and Carolina the latter end of January, and in Virginia in February ; and coaft- ing from thence eaflward to New-England, they divide and go into all the bays, rivers, creeks and even fmall flreams of water in amazing quantities, and continue fpawning in the frefh water until the latter end of April, ■when the old fifh return into the fea, where they change their latitudes by a northward diredion and arrive at New- foundland in May; after which we neither hear or fee any thing more of them in America, until their return amongft us the enfuing fpring, and bring with them a providential bleffing to the poor. Their coming fooneror later up our rivers depends on the warmth orcoolnefsof the feafon: And it is further obferved that if a few warm days invite them up, and cool weather fucceeds, it totally checks their paflage until more warm weather returns. From all which cir- cumftances it appears probable there is a certain degree of warmth particularly agreeable to them, which they en- deavour to enjoy by changing their latitude according to the diftances of the fun. Thus they are found in the Bri- tifh channel in September, but leave it when the fun is at too great a diftance from them in the fouthern hemifphere, and pufli for a more agreeable climate; and when the weather in America becomes too warm in May, (after having depofited their eggs in fhallow water and fecured their young fry from the fifh of prey,) fteer the courfe which leads to the cooler northern feas, and by that pru- dent change of place perpetually enjoy the temperature of climate heft adapted to their nature; which from the table hereto annexed, fhewing the places and times of their vi- fitation, and the calculation of the dirtance of the fun at thofe times from them, is that degree of warmth which is produced by the mean diftance between 37 to 43 de- grees ; except whilft they are fpawning ; during which they bear a greater degree of heat from the necefTity of remaining in it a fhort time to fpawn ; and alfo on the other extreme, when detained at too great a diftance by the iiland of Great-Britain and its dependencies. H h Here 23S On tre annual PASSAGE Here another query occurs, what becomes of the young*- fry, the prockice of the fpawn they left in the frefh waters of America ? We know they do not follow the old ones- the firft feafon, becaufe they are found in great fcooles in all the American bays during the fummer, and difappear in the fall, from whence it may rationally be fuppofed that from their natural propenfity to keep at a certain diftance from the fun, the feafon leads them to a different courfe from the old ones, by which they meet their parentage about the latitude 23° N. and 70° W. longitude, and there tack about and follow the older ones ; which, being larger and fironger than the younger, come firft into our harbours, but are fewer in number than the lefler, probably from, having fuffered great lofs and pillage in their long rout from the fifh of prey, and their greater enemies the fifh- ermen in the different parts of the world. A Table Jheiving nearly about the place of the grand fcoole of herrings^ and their mean dijlance from the fun. * Place and Time. Latitude. Longitude. .Sun's Ue- clinatjon. i he Mean Diftance. I. January, 23 70 20 s. 43 II. February, 32 79 12 44 III. March, 36 IS 36 IV. April, 39 72 loN. 29 V. May, 49 50 19 30 VI. June, 65 15 23 42 VII. July' 58 21 Zl VIII. Auguft, 52 14 38 IX. September, 48 6 48 X. Odober, ZS 22 9 44 XL November, 22 40 18 40 XII. December, 18 52 23 41 • Sec Map B, in Plate V. OF HERRINGS. 239 Sonic Obfervations and Reafons given for the courfe of the Herring;?, and the variatiou iu their Mean Dillance from the Sun in different months of the year. [See Map B, Plate V.] January. In this month the herrings are fuppofed to be returning from too warm a cli- mate and the approaching fun, from which they retreat fall. Februart. The time of fpawning now drawing nigh, the herrings, in this month pafs through the gulph ftream, and fall on the coaft of America, in order to depofit their fpawn ini'relh Ihoal water. March. Now being the beginning of the time of fpawning, the largefl: and flrongcfl fifli, which perhaps are the oldeft, rufh up into the bays, inlets and frefh water ftreams, April. In this month the leffer, weaker, and perhaps younger filh, ruJh up even to the heads of fmal! ftreams, as far as it is poflihle for them to get, and lay their fpawn. Thefe arc twice as numerous as the other. May. Having been detained by the fpawning feafon, they are overtaken by the fun, and nearer to it now than at any other time; they therefore haften out of the rivers in this month, and make great way towards the North fea. June. Now having by a rapid progrefs pufhed Into a cnid climate, on a chilly, icy coaft, and the fun beginning to draw towards the fouth, they whirl round eaftward. July. The coldnefs of this fea, and the fun's declination towards the fouth, now inclines them that way, in which they fall on the Orkneys, and the fcoole divides. August. The grand fcoole being divided, now furround the whole ifland of Great-Bri- tain and Ireland, and are caught on every fide. September. Having been detained the laft month by their obfl:ru(51ion amongft the illands, and being harrafied by the filhermen, their mean dirtance is now tiie greateft ; they colled; into one body and haften to the foutJiward. October. Being now under great way, they lefTen their mcandiftance, and by the courfe which they fteer, which perhaps is incUned more weftward by the current of the trade wind, they pafs the Atlantic. November. Being now more in the trade, and having approached a warmer climate, their motion is fuppofed to incline more weftward. December. The fun now beginning to return, they are fuppofed to incline more north- >vard, to the place where we began ; where they are fuppofed to meet their young fry. N° XXXI, Obfervations on a Solar and a Lunar EcUpfet communicated to the Society by M. M. De Grauchain, Major Ge- neral of the French Squadron. ( Tranflated from the French.) GENTLEMEN, Newport, 5th December, 1720. TH E ftudy of aftronomy having often occupied my leifure during the peace, I could not retufe myfelf even in the midft of the preparations for war, an oppor- H h 2 tunity 24P On eclipses. tunity which prefented of making two important obrerva- tions, which 1 have the honour of fending you. Eclipfes form the bafis of chronology ; this may one day ferve to fix the epocha of the independence of Ame- rica, one of the moft interefting in the hiftory of man- kind. This is a motive to dedicate thefe obfervalions to you ; and I pay this refpedt with the greateft pleafure to an illuftrious fociety, whofe members know how at the fame time to enlighten their country by their knowledge in mathematics and philofophy, and to ferve them fuccefs- fully in their councils and armies. I am, &c. De GRAUCHAIN, Major General of the French Squadron. MESSIEURS, L' ETUDE de raftronomie ayant fouvcnt occiipe mon loifir pendant la paix, je n'ai pa mc refulcr, memc an milieu de I'appareil de !a guerre, a I'occafion qui fut prefentee de faire deux obfcrvations importnntes et j"ai Thonneur de vous les adrcfler. lies eclipfes forment la hafe de la chronologie, et celles cy pourront un jourfervir a fixirTepoque de Tindependance de rAmerique I'une des plus interreffantes de Thil^oire du genre humain. Cell un motif pour vous en dedier les obfervations, meflieurs, et je rends cet hommage avec le plus grand plaifir a une focicte illuftre dont les menibres fcavant en meme temps eclaires Icur patrie par leur connoifances dans les mathematiqucs et dans la phifique, et la fervir utUement dans let confeilb et dans les armees. Je fuls avec refpetft, Meffieurs, Votre trcs humble et tres obeiflant ferviteur, DE GRAUCHAIN, Major general de I'efcadre Francoife. A Newp°" 1' S Novembre, 1780. An OBSERVATION of an ECLIPSE. 241 An Obfervation of an Eclipfe of the Sun on the 27th of Odober, 1780, at Newport in the State of Rhode-Ifland. Time by Clock the True 'I ime. h. / It h. ' • ' ^'hc time that the eclipfe was perceived to begin, 9 24 3i II 12" The preceding limb of the fun at the vertical. II 21 39 57 27 The upper edge of the fun at the horizontal, ir 54 57 42 The upper horn of the moon at tiic horizontal. 1^ 3 57 51 The edge of the moon at the vertical. iz 45 58 33 The tipper horn at the vertical, - - - 23 7 58 SS The lower horn at the vertical, - . . 23 2S S9 23t 20 The lower horn at the horizontal, ... 29 31 I J The lower limb of the fun at the horizontal, 31 J 6 51* The preceding limb of the fun at the vertical, II 37 12 I 13 1 The upper limb ditto at the horizontal. 37 59 13 48 The upper horn ]) at the horizontal, 38 52 14 21 I'he limb ditto at the vertical, - - not obfervetl. The uppef horn ditto at the vertical. 38 57 14 16 The lower horn ditto at the vertical, - - - 39 19 15 8 The lower horn ditto at the horizontal. 4) 38 19 g The lower limb of the fun at the horizontal. AS 27 21 17 The preceding limb Q at the vertical. II 47 8 I 22 58 The upper edge of ditto at the horizontal, 48 17 24 7 The limb of the J at the vertical, - . - 49 24 50 The upper horn at the vertical, - - . 49 5 24 SS The upper horn at the horizontal. 47 7 24 57 The lower limb of Q at the horizontal. 55 30 52 The end of the Eclipfe, . . . - The rate of the clock. II 4 50 r 40 41 At Noon. 1 Oaobcr :i. 10 is 12,8 2i4, 10 29 42,0 2"^, 10 27 52>3 -7, 10 24 IT, 8 * When the fun was perceived to be indented, it was about l' 2o" after the eclipfe began therefore the true time of beginning was at loh. 58' 52". f Uncertain. \ The fupcrior limb is called the inferior, &c. as the glafs of the quadrant Inverted the objeiSs. The latitude of the place of obfervation on Goat- Ifland, 41° 30' 20" N. An 242 OBSERVATIONS on TWO ECLIPSES, An Obfervation of the Ecllpfe of the Moon on the nth of Nov. 1780, at Newport in the State of Rhodc-Ifland. Time by the ( Clock True Time. h. ' t! h. / // The beginning of the Ecllpfe, - - • - 7 40 5 10 24 39 ImmcrCon of Grimaldi begins, ... 7 48 JO 10 33 25 Ditto, - . - ends, ... 7 51 25 10 36 10 Immerfion of Tycho begins, . . - 8 36 10 45 i» Ditto, . - ends, .... not obferved. The fliadow to Gallileo, .... 8 3 42 10 48 18 Immerfion of Copernicus begins, ... 8 ^^ 54 II 12 31 Ditto, ... ends, - . - 8 3^ 3S II 17 12 The ihadow in the middle of Dionyfius, 8 46 55 II 31 33 The Ihadow of the Pointed Promontary, 8 SS 4» II 40 21 Copernicus begins to appear, .... 9 17 54 12 » 34 Grimaldi . . ditto, .... 9 az 2 12 6 41 Copernicus wholly appears, - - - - 9 23 35 12 8 15 Grimaldi - ditto, .... 9 26 45 12 II 26 The Pointed Promontary appears, ... 9 51 12 12 35 55 Tycho wholly appears, ... 10 10 6 12 54 51 The end of the Eclipfe, .... The rate of the Clock, 10 32 10 13 16 57 At Noon. November ir. 9 i5 15,7 12, 9 14 30,7 Remarks iipon the Ohfer'vation of the Ecllpfe of the Sun. THE clock by which the time was obferved, is a pen- dulum one with a verge of compenfation, made by Mr. Parthond, a celebrated clock maker at Paris. It was re- gulated many days before and after the obfervation by correfponding altitudes taken with a quadrant of Ramfden, having a radius of one Englifh foot; it is a very good one and well graduated. The fame quadrant ferved to obferve the time when the horns and limbs of the moon and fun arrived at the hori- Eclairciflements fur I'obfervation de I'eclipfe de Soleil. LA pendule dont on s'eft fervi pour obtenir I'heure eft une pendule a verge de compenfati- on falte par M. Earthond celebre horloger de Paris, clle a etc reglee plufieuri jours avaiit et apres I'obfervation par dcs hauteurs correfpondantes pnfcs avec un quart de circle de Ramfden d'un pied angiois de rayon tres bon, et tres bien divife. Le fnemc quart de cercle a fervi pour les obfervationsdes paflages des comes et des bords du foleil et de la lunc au fil horlfontal, et au fil vertical de la lunette qui y eft adaptee. L'ohfervateur qui en embarquant des Inftnmients d'aftrononiic n'avoit eu pour objet que de reglcr dcs montres marines, n'etoit pas auffi bien pourvu de lunettes que de pendules et de quart de OBSERVATIONS on TWO ECLIPSES. 243 horizontal and vertical threads of the glafs which is fitted to the quadrant. The obferver who provided and fhipped the inftruments, had no other objedl m view but to rectify the clock be- longing to the fliip, which was the caufe that he was not lb well provided with telefcopes as with clocks and qua- drants, he was therefore obliged to make ufe of a fimple achromatic fea-glafs of four feet focus, to obferve the be- ginning and end of the eclipie. Yet he believes he can anfwer for the end of the eclipfe within about four or five feconds. The inftant of time which it began is much more uncertain. The fun was already indented when it was firft perceived, but in order that he might eftimate grofsly the true time of its begin- ning, he has eftimated pretty nearly the diftance of the horns, the moment when the lun's limb was firft perceiv- ed to be indented. By comparing the time elapfed after the end of the eclipfe to the inftant when the diftance of the horns of the moon were fenfibly the fame, hence he judged that it fliould have been about i' 20" from the true time in which the eclipfe began until the obferved time.. At' de cerclc, et 11 a etc oblige de fe fervlr pour Ics obfervatlons du commencement et dc la fin de recliple d'une iimple lunette achromatic de mer de quutre picds dc foyer. Cepcndant on croit pouvoir repondre de la fin de reclipie a quatre ou cinq fecondes pres ; • I'inflant du commcn:ement eft beaucoup plus incertain ; le folLil etolt deja coniiderablenient cntanic, lors qu'on s'cn eft appercu : pour conclure au moins gronierement i'inftant vrai du- commencement dc reclipfe, on a eftime a peu pres quelle etoit la diilance dcs cornts au mo- ment ou on s'eft appercu que le difque du loleil ttoit entamc, et vers la fin de TecHpfe on a examine combien il s'eft ecoule dc tenis depuis I'inftant ou la diftance des cornes a eie lenfible- ment la memc jufqu'a la fin de reclipfe. C'eft dc cette maniere que Tun a juge qu'il devoit s'etre ecoulc environ l' 2<^' depuis I'inftant vrai du commencement de Teclipfe, jufqua celui ou on s'eft appercu, quelle etoit commencee. On a dabord cru inutile de cbcrcher a obferver la grandeur de I'eclipfe avec le quart de cer- cle, a caufe de la lenteur du movement des deux aftres duns le fens vertical, cepcnd.mt a Ja re- flexion on a penfj que les paffages des cornes et des bords du foleil et de la lune au fil vertical fdulen.ent fuiiirolent pour donner les differences de hauteur ct d'azimuth des centres des deux aftres, et par confequent leur diiference de latitude et de longitude. On les a done obferves vers la fin de I'lclipfe, et en meme terns on a obferve les paffages au fil horifontal, mais fans cfpcrer qulls puftcnt etre d'un grand fecours pour calculer la diftance des centres. Dans la premiere obfervation le paflage de la corne fupcrieure au fil vertical eft un pen dou- teux. On penfe done qu'il eft a propos d'cmployer de preference dans le calcul de cette obfer- - Tutlon les paffages du bord de la lune, et de la corne inferieure au meme fil vertical. De cette maniere on connoitra immediatement les lignes NB et C O dont la premiere combinee avec les deux diametres L N et S T donnera L E ; difference d'azimuth des centres des deux aftres. On obtieiidra aulli facilcmcnt la difiVrence appareute de hauteur iS E des memes centres en cai- cubnt - 244 OBSERVATIONS on TWO ECLIPSES. At firft it was thought ufelefs to endeavour to obferve the magnitude of the eclipfe with the quadrant, becaufe of the flow movement of the two planets vertically, yet upon reflection he thought that the paflage of the horns and limb of the fun and moon to the vertical thread only, would be fufficient to give the difi^erencies of the altitude and azimuth of the centers of the fun and moon, and of courfe their difference of latitude and longitude. He then obferved them towards the end of the eclipfe, and at the fame time obferved the time of their arrival at the ho- rizontal thread, but without any expedation of their be- ing of great fervice to calculate the diftance of the cen- ters from. In the firft obfervation the paflage of the upper horn to the vertical thread, is a little doubtful ; at the time it was thought proper to give the preference to the paffages of the limb and lower horn of the moon to the fam.e vertical thread, in making the calculations from this ob- r'"re"i'8 Nervation ; by this means we may find the lines NB and CO, the firft of which combined with the two diameters LN and ST will give LE, the difference of azimuths and of the centers of the two planets; the apparent difference of the altitude from the lame centers may be eafily obtained, by calculating SF and CM, fides of the right-angled triangles CSF and CLM, in which are known the other two fides. In eiilant S F et C M cotes des triangles reflangles C S F et CLM dans les quels on connoit deja les deux autres cotes. Dans la feconde obfervation on a obmis par dillraftion, I'inftant du paflage du bord de la lune all fil vertical, on fe fcrvira done pour la calculcr des paffages des comes au meme fii les quels donneront immediatcment C A et C O d'ou fouftrayant S T, on aura CD et C F con- noiffant ces deux lignes et le demi-diametre du fokil on calculcra les angles C S D, CSF fouftrayant leur fonime de ioo°, on aura Tangle C S L partageant cet angle par la moitie on aura Tangle C S L du triangle C L. S, on connoitra done aiiement S L cote de cetriangle et du triangle S L. E calculant enfin ce dernier Jriangle S L E dans le quel on connoit deux angles ct un cote on obtiendraL E; difference d'azumuth et 3 E ; difference apparente de hauteur des centres des deux aftres. La derniere obfervation etant plus complette on pourra la calculer indifTerement de Tune ou Tautre maniere. On pourra meme faire ufage du paffage au fil horifontal pour conclure la dif- ference de hauteur attendu que le movement des deux allres dans le fens vertical commcncoit a dcvenir moins lent lorfque cette obferv'ation a ete faite. Si OBSERVATIONS on TWO ECLIPSES. 245 In the fecond obfervation we obtain the Inftant of the arrival of the Hmb of the moon to the vertical thread, which may be made ufe of to calculate the paflage of the horns by the fame thread, by which C A and C O are obtained : By fubtrailing S T from thcfe, the remain- der will be C D and C F, having thefe two lines and the femi-diameter of the fun, the angles C S D, CSF, may be had, and fubtrailing their fum from 180° the remain- der will be the angle CSC, the half of which is the angle CSL; from the triangle CSL you may readily obtain SL, a fide of this triangle, and of the triangle SLE ; from thefe at length this lall triangle SLE, may be calculated, in which are had two angles and one fide, from which may be obtained LE the difference of azimuth, and SE the apparent difference of altitude of the centers of the fun and moon. My laft obfervation being more complete, might be calculated either from the one or the other method, and the palfage to the horizontal thread might even be ufed to determine the difference of the altitude of the centers, as the motion of thefe planets with refpeft to the vertical, began to be quicker when this obfervation was made. If we are defirous to afcertain the time of the paffage of the upper horn of the moon to the vertical thread in the firft obfervation, or to know in the fecond obfervation the time of the paffage of the limb of the moon by the fame thread, they may eafily be calculated by the help of the quantities already found. Perhaps it might be ufeful to make this calculation, to determine the variation which ought to have place in the pofition of the two points obferved, I i relatively Si I'on vouloit dans la premiere obfen'ation verifiier Tinftant du palTao^c de la cornc fupc-. ricure au fil vertical, ou connoitre dans la feconje ohfervaiion riiiitant dii pafra9;e du bord de la lune au nicme fil on pourroit aifemcnt les calculer avec le focours des tjuantites deja connues. U fera peutetre meme utile de faire ce calcul pour fc mettre en etat de determiner la variation qui a du avoir lieu dans la pofition des deux points obferver relativement I'un a I'iJtre, pendant I'efpace de terns ecoule cntrc leiu's pafl'ages au mcmc fil. Obferration 246 TRANSIT or VENUS relatively to each other during the time elapfed between: their paffage to the fame thread. Obfervation de I'eclipfe de Lune. ON a fait ufnge dans cette ohfervation de la meme quart de cercle, et de la meme lunette, qui avoient fervi pour I'obfervation de I'eclipfe de foleil. La marche de la pendiUe etoit ce- pcndant unpeu ditl'erente parte qu'on y avojt touche.. N° XXXIL An Accoufit of the Tr unfit of Venus over the Sun, June 31^, 1769, as obferved at Neivhury-, in Maffachufett s ; by the Rev. Samuel Williams, A. M.. THE tranfit of Venus over the fun, being one of the mofl: uncommon and ufeful phenomena in aftrono- my, I determined to make as careful an obfervation of it as I could. Early in May I received an invitation from Tr'ijlram Dalton, Efq. a gentleman of Newbury-Port, to obferve it with him. He had a feat at Newbury, in a high elevated fituation, very convenient for this purpofe, at which we agreed to make the obfervation. The wea- ther for feveral days had been dull and rainy, but clear- ing up on Tuefday evening 1 went early on Wednefday to put every thing in readinefs. The regulation of our clock being an aiticle of great importance, I was very careful to have it thoroughly examined, and well fitted up. To adjuft it to apparent time we took correfponding altitudes of the fun, both before and on the day of the tranfit. In thefe obfervations, it was eafy to arrive to a pretty great exa£tnefs; and as they were very numerous, the going of the clock was well afcertained by them, and found to be fteady and regular. The telefcope we had prepared was a refledlor made by Ndirne, magnifying about ^^ times; a good inllrument, but not fitted with a micrometer, OVER THE SUN. 247 micrometer, or with vertical and horizontal hairs, as we could have wiflied. The third of June proved favourable to our wifhes. The air was uncommonly clear, and the fky ferene. About twenty minutes before the tranfit, I began to keep mv eye fteadily fixed on that part of the fun's limb, on which the planet by calculation was to enter; an afliftant counting the clock in the mean time, while another Hood by to write down the obfervations. Thus prepared, we waited with a kind of agreeable anxiety for the high fa- tisfadtion of feeing Venus on the fun; a fatisfaiflion I had once before enjoyed in viewing the tranfit of 1761*, and which I knew muft end with that of 1769 ! The firft im- preffion of Venus on the fun, I expeiled would not ap- pear like a diftind: well defined black fpot coming on as it were in an inftant, but rather like an ill defined mix- ture of limbs. The event was agreeable to the conjec- ture, for at 2^ 30' 14", apparent time, I imagined I faw afniall dijitirbance on the fun's limb; but the impreffion was then fo fmall, irregular and ill defined, that it was not till after feveral feconds that I was certain the tranfit was begun. But the impreffion increafing and growing more diftindl, I fixed on the time mentioned above as the time of the external contaEl. To obfervers with tele- fcopes and eyes equally good, and fixed on that part of the fun on which the planet entered, I conceive this firfl: im- preffion might have been obferved to an agreement of 5 or 6 feconds. Though perhaps it might be the contad: of the atmofphere, rather than of the body of Venus with the fun. In about ten minutes after the external^ I began to look for the internal contad. From the form in which Venus appeared, being furrounded with a glimmering light, not very diftin£tly defined, I concluded it would be difficult if not impoffible to fix upon the precife moment when her I i 2 limb * At St. Johni, ill NeivfoundlmJ. ^rR*--^ 24S TRANSIT OF VENUS limb would be exadlly coincident with that of the fun; and therefore determined to wait till there fliould appear a fmall thread of light between them. As the contadt draw- near, the thread of light began to form, and feemed to dart on each fide of the planet for feveral feconds without being fixed or fettled. At 2^ 48' 44", with a feeming uncertainty of not more than 7" it became clofed and fix- ed ; Venus then appeared wholly within the fim, feparat- ed from its limb by a fine ftream of light flowing gently round it. T his T fixed upon as the internal contact-, though this might alfo be the contad: not of Venus but of her atmofphere with the fun. Not having a micrometer or hairs fixed in the refledtor, inftead of making any further obfervations, we could only enjoy the pleafure of viewing this curious phenomenon, and fhowing it to a number of gentlemen that had affembled on the occafion. To determine the latitude of the place, we took the meridian altitude of the fun on the day of the tranfit, by tranfmitting his rays from a ftyle 10 feet high, upoh a large horizontal platform. Prom this obfervation our la- titude came out 43° 2' north. Sufped:ing the obfervation was not fufficiently accurate, I have fince carefully exa- mined the matter, and from feveral obfervations which nearly agree, I find it to be but 42° 57'. With regard to our longitude, the mean of fix or feven obfervations of the eclipfes of Jupiter's firft fktellite, gives it about 4'' 42' 30" weft from Greenivich. In the above account of the confabs, the duration of the ingrefs, or palfage of Venus over the fun's limb, is 18' 30"; near a minute longer than in moft of the Ame- rican obfervations. By theory it fhould be 18' 56", but as this muft have been contrafted at the place of obferva- tion, 15", by parallax, the apparent duration of the in- grefs, would be but 18' 41"; that is, 11" longer than it was made by oblervation. I much doubt whether it was poffible to difceru the planet fo foon as 11" after the firft OVER THE SUN. 249 firft contad, when not a fecond of its dianieter had enter- ed upon the lun. It is raoft probable that the internal contacl was paft before the thread of Hght appeared to me to be compleated. It feems as though fomething of the fame kind, mufi; alfo have been the cafe in moft of the European obfervations; as they make the ingrefs near a minute longer, than it was feen by moft of the American obfervers, when by theory it muft rather have been Ihort- er. But the different appearances of Venus, different ideas of the contacts, with the unavoidable difference of eyes, telefcopes, the ftate ot the atmofphere and the like, might eaiVly occafion fuch differences in the obfervations. Though in the lame circumftances, it can hardly be thought but that the European and the A7ncrican obferva- tions would have more nearly agreed. An Account of the Tranfit of Mercury over the Sun, No- i^evihcr C)th, 1 769, as ohferi'ed at Salem., in Majfachu- fetts ; by the Rev. Samuel Williams, A. M. THE tranfits of Mercury, though they are not of equal ufe in allronomy with thofe of Venus, are yet of great ad- vantage to perfeifl the elements of his theory, and to de- termine the longitude of places on the earth. I had an opportunity to obferve one of thefe tranfits, November 9, 1769, in company vv^ith Anclreiv Ohver, Efq. at Salem. Mr. Oliver had a good refleiStor, magnifying about fixty times. But his clock not being in fo good order as was to be wilhed, and not having any inftrument to take al- titudes, I was obliged to have recourfe to the following method to determine the time. The day before the tran- fit I drew a meridian line, with \> hlch I examined the going of the town clock on the day ot the tranfit, and on the day after, and found it had kept time very well. Compariiig my watch with the clock, the time was point- ed out to minutes pretty exactly. Taking the minutes from. sjo TRANSIT OF MERCURY. from the watch, I endeavoured to count the feconds, which by a perfon ufed to it may be done pretty near the truth. This method of determining the time, though fuch as an aftronomer would by no means chufe, was the only one that I could make ufe of; and from the pains I took to be exadt, I believe it might be depended upon to eight or ten feconds. At xhcfrjl contaB I expected Mercury would have ap- peared as Venus had done, fomething irregular, uneven, and not very diftindly defined. But at a* 54' 40" appa- rent time, I was agreeably difappointed by feeing the pla- net come on as it were in an inftant, in the form of a clear, regular, well defined black fpot. The internal con" /^(f? was equally inftantaneous; at 2'' ^G' o" the thread of light clofed to appearance i%a moment, without a Teem- ing uncertainty of a fecond. The fky being perfectly clear and ferene, nothing could be better defined than the limbs of Mercury and the fian. There was no appearance of any thing like an atmofphere round the planet, but all the time the fijn was vifible, Mercury appeared like a fteady diftindl black fpot, much lefs than fome that were then upon the fun. Not having a micrometer, it was not in our power to make any further obfervations, either on the diameter of the fun or Mercury, or of the leaft diftance of their limbs. An Obfer'vat'ion of an EcVipfe of the Sun, November 6thy 1 77 1, at Bradford, in Majfachufetts ; by the Rev. Samuel Williams, A. M. FROM the beginning of the year 1769 till the end of 1 77 1, there were but two eclipfes that could be obferved at Bradford. One of thefe was a total eclipfe of the moon, June 19th, 1769 ; of this I had no obfervation, being prevented by an indifpofition. The other was an eclipfe of the fun, November 6th, 1771. The weather for feve- ral ECLIPSE Of THE SUN. 251 ral days before, was fo cloudy that I attempted in vain tO' regulate my clock, though I watched every favourable opportunity. On the day of the eclipfe I got it pretty well adjufted by feveral correfponding altitudes of the fun. About i"" p. M. the clouds gathered fo much round the fun, that I was apprehenfive they would prevent any ob- fervation. But being pretty much fcattered, at i'' t^G 42" apparent time, I could very plainly perceive that the eclipfe was juft begun. This I judged was very near the beginning, if not exadtly fo, though it was attended with fome uncertainty. In a few minutes the fun was wholly covered with the clouds, and remained thus till 34-'', when they began again to fcatter, and left that part of the hea- vens in which the fun appeared, perfedlly clear. The weather continued thus till the end of the eclipfe, which by a good obfervation was at j*" 47' 2". Thefe obfervati- ons were made with a refledtor made by Nairne^ magni- fying as near as I could judge about fixty times ; but as to the quantity of the eclipfe, no obfervation could be made, the fun being obfcured by the clouds the biggcft part of the time. N° XXXIII. An eajy and accurate Method of finding a true Meridian Line-, and thence the Variation of the Compajs. By Robert Patterson. Read Apr. ^'^ F the various methods which aftronomers 7, 17 • \^^ employ for finding a true meridian line, none feems fo well adapted, as could be wiihed, to the common ufe of furveyors, in finding the variation of the Compafs. To find the azimuth of the fun by a fingle obfervation of his altitude, befides a quadrant which is neceffary fo thi. 252 An easy method of finding the this purpofe, requires the previous knowledge either of the latitude of the place, or hour of the day, at the time of obfervation; neither of which can, by the common ap- paratus of a furveyor, be found with fufficient accuracy. The fun's azimuth may, it is true, be found without knowing either the latitude of the place or hour of the day, by taking equal altitudes before and after noon; but this requires time, attention and inftruments, which fur- veyors can but feldom command. That method, which is perhaps the moft exail, viz. meafuring the time between the pafTage of two ftars which differ confiderably, in declination and but little in right afcenfion, over the fame vertical circle, is ftill farther out of the reach of comnion furveyors. The following table of the pole ftar will, it is prefum- ed, furnifh a more eafy, and yet fufliciently accurate me- thod of determining this problem; free from all the above inconveniencies, and requiting no difficult calcula- tion, nor any other inftrument than the common theodo- lite, or circumferentor. For though the latitude of the place {hould not be known within a whole degree, nor the hour of the night within 2 or 3 minutes, this table, by a fingle obfervation of the magnetic azimuth or bearing of the pole ftar, will generally give the variation of the needle true to a fingle minute of a degree. Nay if the ob- fervation be made (as it may be every night) when the ftar is near its greateft elongation, an error of 10, or even 20 minutes in time will, as is plain from the table, produce lit- tle or no fenfible error in the azimuth. And as thefe obfer- vations may be repeated at pleafure during the night, and a mean of all taken, the variation may, by this means, be found to any degree of accuracy that can be defired. Be- fides, the needle is not at this time aifciSed with any di- v;rnal variation; which in the day-time is very uncertain, and frequently amounts to more than one quarter of a degree. The VARIATION OF THE COMPASS. 253 The beft inftrnment for obferving the flar's magnetic azimuth is a theodolite, furnifhed with fpirit-lcvels, and a fmall telelcope with a perpendicular wire. A common circumferentor may, however, anfwer the purpofe. When this inftrument is ufed, a fine thread or hair mud be ftretched along from the top of one fight to that of the other, directly over the center of the compafs ; and the obferver muft be very careful to place the figlits perpen- dicular to the horizon when he makes the obfervation ; for this purpofe a fmall pocket fpirit-level, in the form of a carpenter's fquare, would be very convenient. By the common circumferentor we cannot, indeed, take the bearing of an objedt with very minute accuracy ; for though the eye can very well judge of the coincidence of two lines, or of the point of the needle with any whole degree on the compafs, yet the parts of a degree cannot readily be obferved to greater exadlnefs than one third or one fourth of the whole. This inconvenience may, how- ever, be eafily remedied, and at a very trilling expence, in the following manner. Let one of the fights, by means of a fcrew, be made movable at right angles to the index ; and on the end of the index, clofe to the movable fight, fet off, on each fide of the central line, the tangent of three degrees to a radius equal to the whole length of the index, or diftance between the two fights. Let each of thcfe degrees be divided into fix equal parts ; then will a nonius divifion on the fight, where ten equal parts mufl; correfpond with eleven on the index, fubdivide thefe parts into minutes of a degree. It will be unnecelfary to make the fight move in the arch of a circle, the difference between this and the tan- gent, in fo fmall an arch, being quite imperceptible. With this finiple improvement the common circumferentor will take the bearing of an objedt true to a minute, thus : Let the end of the needle be made exadly to coincide with the K k nearefl £54 A^ EASY METHOD of finding thi nearefi: whole degree, then move the fcrew till the obje£t appears in the diredlion of the fights, and the nonius on the movable fight will point out the odd minutes. Explanation and Ufe of the Table. The left hand double column of the table contains the time before the ftar's pafTage over the meridian above the pole, for every twenty minutes of its whole diurnal circuit. The firft column, under each particular latitude, fhews the azimuth of the ftar at thefe times, refpe£tively, in de- grees, minutes and tenths of a minute. The fecond co- lumn fhews the difference of azimuth in every twenty minutes of intermediate time, in minutes and tenths. To find the true azimuth of the ftar in any latitude, at any given time. From the ftar's right afcenfion, viz. o*" 49", increafed by 24'' if neceflary, fubtra£t the right afcenfion of the fun computed to the time of the ftar's paftage over the meri- dian, above the pole, nearly, the remainder will be the time of faid paftage, reckoned from noon. From which, increafed by 24'' if neceffary, fubtradl the time of the ob- fervation, reckoned alfo from noon, the remainder will Ihew the time before the ftar comes to the faid meridian. Look for this time in the left hand column of the table, oppofite to which in the column of azimuth, under the proper latitude, you will have the true azimuth of the ftar at that time. If the time before the ftar comes to the meridian be lefs than 12 hours, its azimuth will be eafterly ; but if more than 12 hours, its azimuth will be wefterly. If the magnetic azimuth, and the true azimuth at the time of the obfervation, be both eafterly or both wefterly, their difference will be the variation of the needle. But if one be eafterly and the other wefterly, their fum will be VARIATION OF THE COMPASS. 255 he the variation. And if the magnetic be to the weftward of the true azimuth, the variation will be wefterly ; but if to the eaftward, the variation will be eafterly. If the time before the ftar's paffage over the meridian be fome intermediate minute, or the latitude of the place fome intermediate degree, not found in the table, a pro- portional intermediate azimuth, by means of the differ- ences, muft be taken. The right afcenfion of the pole ftar annually increafes 10 feconds of time, and its polar diftance decreafes 20 fe- conds of a degree, therefore to its prefent right afcenfion (in 1785,) viz. o"" 49", muft be added one minute every year; and from its prefent polar diftance (i ° 50'. 5) one minute muft be fubtraited, and a proportional part from all the numbers in the columns of azimuth, every three years. The eff^ed; of aberration and nutation may be fafely neglected; as the error arifing from thefe caufes can never amount to more than half a minute of a degree in azimuth. In computing the fun's right afcenfion to the time of the ftar's paftage over the meridian nearly, the following little table will be ufeful,- Kk2 TABLE. 256 An easy method of finding the TABLE. Time, Star paffes Meridian nearly at April 2 Noon 19 II A. M. May 5 10 20 9 June 4 8 18 7 July 3 6 17 5 Auguft 2 4 17 3 September 3 2 19 I Oaober 6 Midnight 22 II P. M. November 6 10 21 9 December 5 8 19 7 January i 6 ^ii 5 29 4 February i 3 3 March I 2 17 1 Ex A MPLE I. Suppofe on the 12th of September 17S5, at 8 o'clock in the evening, in the latitude of 40° N. the magnetic azimuth of the pole-ftar had been obferved to be 0° 38' eafterly ; required the variation of the needle at the time and place of obfervation. Star's VARIATION OF THE COMPASS. '^Sl II 25 13 8 24 H. M. Star's R. A. increafed by 24 hours, - 24 49 Sun's R. A. computed to i'' A. m. (taken from the nautical almanac, or any other table of the fun's R. A.) fubtrad True time of ftar's paflage over meridian, reckoned from noon, Hour of the night fubtradt. Time before ftar's paflage, - - 5 24 Which correfponds to true azimuth, 2° 23' E. Magnetic azimuth, - - o 38 E. Variation of the needle, - i 45 W. Example IT. In the latitude of about 32° north, on the 4th of July 1789, at 48 minutes after i d o'clock at night, iuppofe the magnetic azimuth of the pole flar, to be 2° 40' eaft; re- quired the variation of the needle. Star's R. A. + 24% - _ _ Sun's R. A.- - - - _ Time of ftar's pafling meridian. Time of obfervation, _ _ _ Time before ftar comes to meridian. Which correfponds to true azimuth, 2° 4' E. Magnetic azimuth, - - 2 40 E. Variation, - - o 38 E. Ex- H. M. 24 49 6 54 17 55 10 48 258 An easy method of finding tre Example III. Latitude of the place 42 ° north, tune of obfervation,, January 17th 1785, at 2" 40™ A. M. Magnetic azi- muth, I ° 5' eafterly. Star's R. A. + 24* _ _ -_ Sun's R. A. - - - _ Time of ftar's paffing the meridian, Time of obfervation reckoned from noon, Time before ftar comes to meridian, - 14 8 Correfponding to true azimuth, 1° 16' W. Magnetic azimuth, - - i 5 E. Variation, „ - - H. M. 24 49 20 I 4 48 24 28 48 H 40 2 21 E. A Table VARIATION OF THE COMPASS. 259 A Table of the Azimuth of the Pole-ftar for every 20 Minutes of its diurnal Motion round the Pole. ■ Latitude 30' :Latitude35^ Latitude 40° Latitude 45° Latitude 30^ Latitude.sj i iTinic before thi 1 ilar comes to 1 the meridian a- 1 bove the pole. i5 it; 5 0^ 3 m 3 2 £ Q 5 'i-5 5 H. M. c 20 40 H. M. 24 c 23 4C 2C 0.0 "•3 22.6 1 "■3 "■3 ri.i 10.7 10.4 lo.o 9-5 3.9 8.2 7.6 6.7 5-<) 5.0 41 3-1 2.2 1-3 / 0.0 1 I2.0 1 24.0 1 12.C 12.0 11.; II..'; II.O 10.6 lO.O 9.4 8.8 7.8 7-1 6-3 5-2 4-3 3-3 2.', 1.4 3 / 3 0.0 12.9 25-7 12.9 12.8 12.6 12-3 II.9 "■3 10.9 lO.O 9-3 8.J 7-5 6.7 S-S 4-5 3-6' 2.4 1-3 / 0.0 14. 1 28.0 t 14.1 13-9 13-7 13-4 12.9 12.3 II. 8 10.9 10. 1 9.1 8.2 7.2 6.0 4-9 3-7 2.. I..- 3 0.0 15.6 31.0 15.6 15-4 1 0.0 17.6 35-0 17.6 17-4 17.2 16.7 16.0 15-4 14-5 ^3-S 12-5 ri.2 lO.O 8.7 7-3 6.6 3-6 3-0 •1-4 I 20 40 C 22 4C 2C 33-7 44.4 54-8 35-7 47-2 58.2 38.3 50.6 I 2-5 41-7 J.T-i I 8.0 46.2 I I.O 15-3 IV. 14.8 14-3 X3.6 12.9 12.0 II. a lO.O 9.0 7-7 6.6 5-4 4.0 2.6 1.4 52.2 I 8.9 24.9 i 20 40 C 21 4C 20 r 4.8 14-3 23.2 I 8.8 18.8 28.2 13-8 24.7 34-7 20.3 32.1 43-0 28.9 41.8 53-» i 40-3 1 J4.8 2 8.3 3 ao 40 G 10 4C 2C 31-4 3y-o 45-7 37-0 44-8 51.9 44.0 2 0.0 J3-I 2 2.2 10.4 2 5-0 i.?.o 24.0 31-7 38.3 43-7 20.8 32.0 42.0 4 20 40 C 19 40 2C 51.6 56.6 2 0.7 58.2 1 3-4 , '-7 6.7 12.2 16.: 17.6 23.6 28..C 50.7 58.0 3 4-6 S 20 40 18 40 ic to 7.3 j 11. 13-3 1 14-7 20. .3 22.7 24.C 32.2 34-- 36-1 47-7 50.3 iI-7 8.2 II. 2 12.6 6 2C 4C 17 40 20 7.6 6.9 5-2 •7 1-7 2-5 3-5 4-J 5-1 6.2 6.8 7-5 8.2 8.8 9-3 9-7 10.2 10.5 10.7 10.8 10.9 j 14.8 1 14-2 i 12.3 .6 1.9 2.8 3.8 4.6. 5-6 6.4 7.3 7-9 8.7 9.2 9.8 TO.,-i 10.7 II.C II..- ri.i 1 1-5 24.2 21.3 •9 2.0 3-0 4.1: J.O: 6.0* 6.9' 7.6 9.4 9.9 10.4 II.O II. 4 II. 7 12.0 12.2 12.2 36.^ 33-^ l.C 2,3 3-3 4-.'; 5-i (,.;. 7-5 8.5 9.2 9-9! 0.8; :i.3 ti.8' ^i-3 '3-7 12.9 I3-I 13.2, 31.8 50.7 48.2 I.I 2-5 3-9 4.9 6.2 7-1 8.4 9.2 10.2 II.O 11.7 12.4 12.9 13-4 1 14-0 14-2 14-3 14.4 1 12.5 ' II.O '-S 8.i| ^-9 7 2C 4C r6 40 2C 2-7 I 59-J 54-7 9-5 5-7 i.i 18.3 14-2 9.2 29.7 23.2 19-7 44-3 39-4 3.3-2 .3-8 2 58.2 iI-2 4- J 5-6 7.0 8.2 9-3 10.4 II-5 12. 1 13-2 13.8 14-5 14.9 15.6 15-7 15-9 16.1 8 c 20 4C c 15 40 2C 49.6 43-1 36.^ I 55-5 49.1 41.8 3-2 I 5<>-i 48.7 13-2 5-7 I 57-2 26.1 17-7 8.5 43-0 33-7 23-3 9 f 2C 40 14 40 2C 29.1 20. (; 12. 1 33-9 25.2 16.0 40.2 3c. 8 20.9 48.C 38.1 i7-.- = 58.3 47-3 3.?.6 1 1.8 I 59-7 46. .V 10 < 2(_ 4C '3 4ci 2C' 2.' ^ .?3-'' 42. V 6.2 -> 55-9 45-2 34-2 22.9 "•5 0.0 10.5 5 59-5 48.1 16.. 4-; 51.9 23.2 10.3 36.9 32.7 18.2 3-3 11 c 2C 4r 12 C C 12 40 20'; 0| 32-i 21.; 10.9 0.0 36.4 24.4 12.2 0.0 39-^ 26.3 I3-i 0.0 42.9 28.7 14.4 0.0 47-7 32.0 16.I 0.0 [ 260 ] N° XXXIV. Agronomical Ohfervations, communicated hy Mr. R i t- TENHOUSE. By Mr. 'James Six., of Canterbury. Geocentric place of the New Planet. April ift, 1782, 29° 5' 30" in n lat. 13' N. October 15th, 7 21 18 gs nearly ftationary. December 26th, 5 2 30 in oppofition. March loth, 1783, 3 15 o ftationary. Odlober 15th, 11 ^^ 10 ftationary. December 30th, 9 47 25 in oppofition. March 14th, 1784, 7 46 o ftationary. Lat. 23 N. By D. Rittenhoufe^ at Philadelphia. Tranfit of Mercury over the fun's difts, Nov. 12th, 17S2. Firft external contadl, 9" 34' 50" morn. ^ Internal, uncertain, 40 o \ Second internal, 10 51 30 j^McanTimc. Laft contact, 57 35 -^ Greateft diftance of 5 center from fun's limb, 31". 1784, On Meridian. Jan. 2yth. v Gemino 9" 49' 20" ' Gem. 9 54 45 New Planet 10 i 48 ^ Gem. 10 15 19 Feb. 1 2th. y Gem. 8" 54^" New Planet, 9 4 54 I, Gem. 9 20 18 ASTRONOMICAL OBSERVATIONS. 261 • 7?;. On Meridian. January 26th. ^ Gemino I oh H' 14' New Planet 10 3' 22 i Gem. ^ Gem. ID 40 7 February 4th. 9 48 48 New Planet 9 54 32 S Gem. 10 4 41 r^ Gemino 19° 5' 7' Feb. 1 2th. Obfe rved zenith difta: nee, < New Planet 16 40 45 OGcm. 17 35 33 Febr. i7tli. t Gem. 8h 57' 42" New Planet 9 I 46 zenith diftance, 16° 40' 42'' S-Gem. 9 13 35 ditto, 17 3S 40 Febr. 27th. ?Gem. 8 18 34 New Planet S 2 I 32 Gem. 8 34 27 March 1 2th. CGem. 7 ^7 H New Planet 7 29 414 J Gem. 7 43 6i March 15 th. Sirius t 6 59 51 ^ Gemino 7 >S 30 New Planet 7 17 54 2- Gem. 7 31 23 M.irch 17th. Sirius 6 51 58 ^ Gem. 7 7 37 New Planet 7 y 59 March 2 2d. Sirius 6 3* 18 ^Gem. 6 47 56 New Planet 6 50 19 March 27th. Sirius 6 12 38 ^Gem. 6 28 16 New Planet 6 30 45 aSth. ^Gem. 6 24 19 New Planet 6 26 Soi W [icrometer mea- Difference I'li 178'^. fure of Z. D. miii. &. feco. January 25th. ?■ Gemino loh 45' 1" New Planet 10 5\wwfoit le meme hom- nie que ce Martin Behin^rc mentionne par Garcilaflb; mais cette conjeflure vague axira tous jet caracleres de rcviJence par les details fuivans. I.'hifloirc DISCOVERY OF AMERICA. 267 The literary hiftory of Germany gives an account of a Martin Behem, Beheim, or Behin, who was born at Nur- enburgh, an imperial city of the circle of Franconia, of a noble family, iome branches of which are yet extant. He was much addidled to the ftudy of geography, agro- nomy and navigation, from his infancy. At a more ma- ture age he often thought on the poflibility of the exi- ftance of the Antipodes and of a weftern continent. Fil- led with this great idea, he paid a vifit in 1459 to IfabelJa daughter of John the I. king of Portugal and regent of the duchy of Burgundy and Flanders. Having informed her of his defigns, he procured a veffel, in which he made the difcovery of the iiland of Fayal in 1460. He there eftablifhed a colony of Flemings, whofe defcendants yet exift in the Azores; which were, for fome time called the Flemifh iflands. This circumftance is proved, not only by the writings of cotemporary authors, but alfo by the manufcripts preferved in the records of Nurenburg, from which the following is copied. " Martin Behem tender- " ed his fervices to the daughter of John king of Lufita- *' nia, who reigned after the death of Philip of Burgun- " dy iirnamed the Good, and from her procured a fhip, *' by means of which, having failed beyond all the then " known limits of the weftern ocean, he was the firft vi^ho, " in the memory of man, difcovered the iiland of Fayal, " abound- - L'hifloirc litteraire de I'AUemagne nous apjircnd que ATtirlhi Brhem, Beheim ou SJjin eft ne a Nurenhcrg, ville imperiale du ccrcle dc Franconie, d'unc faniille noble dont quclqi-ts branches exiftent encore aujourdhui. Des fa plus tendre jcunefTc il fe livra a I'etude de la geographic, de I'ailronomie et de la navigation. Parvenu a un age mur il rcflechit beaucoup" fur la pof- fibilite d' Tcxiftence des Antipodes et d'un continent occidental. Rempli de cette grande idc'e, i'l fut trcuver en 1459 'fabelle fille de Jean 1. roi de Portugal et regentc du duche de Bour- gognc et de Flandre. Apres lui avoir fait part de fes projet5, il en obtint un vaifleau avee lequel il fit, en 1460, la decouverte de I'ifie de Fayal. II y etablit une colonic Flamande, dont Ics de- fcendanse-xiftent encore .lujour-.ihui aux Azores, qu'on a appellees pendant quelque terns les ifles Flaniandes. Cette circouftance elt prouvee, non fculemcnt par les auteurs contemporains, mais par des manufrrits conferves dans les archives de Nurenberg, dnnt voici la copie : " Martinus " Behemus, Joannis laiDtania; regis filis, quK port obitum Philippi Burgundi cognomento " boni, reruni doniinabatur, operam fuam addixit, et ab ca navim impetravit, qua occidentalis *' oceani haelenus cognitos terminos et fines pr^tem'edlus /t/w/.-j poft hominum memoriani " Fayakm inXulam, Fago arbore, quam LuQtani Fa^jc vocant, ac unde ajipellatio ci ha:Ct abun- " danteni ^68 MEMOIR ON THE " abounding with beachtrees, which the people of Lufita- " nia call Faye; whence it derived its name. After this " he dilcovered the neighbouring iflauds, called by one " general name the Azores., from the multitude of hawks " which build their nefts there (for the Lufitanians ufe " this term for hawks, and the French too ufe the word " EJfos or Ejores in their purfuit of this game) and left " colonies of the Flemiih on them ; when they began to " be called Flemifh iflands, &c." Although this record is contrary to the generally received opinion, that the Azores were difcovered by Gonfalva Velho, a Portuguefe, yet its authenticity cannot be doubted ; it is confirmed by feveral cotemporary writers, and efpecially by Wagenceil, one of the moft learned men of the laft century ; who after hav- ing travelled into Africa, and throughout all Europe, was made do£lor of laws at Orleans and chofen fellow of the academy of Turin and Padua, although he was a Ger- man by birth. The particulars are to be found in his imiverfal hiftory and geography. I have moreover re- ceived, from the records of Nurenberg, a note written in German on parchment, which contains the following facfls. " Martin Behem, efquire, fon of Mr. Martin Behem of " Schroperin, lived in the reign of John II. king of Portu- " gal, in an illand which he difcovered, and called the ifland " of Fayal, one of the Azores, lying in the wellern ocean." After having obtained from the regent Ifabella a grant of Fayal, and refided there about twenty years, during which " dsntem reperit, nee minus poftea finitimas infulas, imo nomine ab acclpitrum ibi nidifican- *' tium multitiidine Ai^ores diclas (Lufitani cnim hoc vocabulo accipiiris elTi^runt, et Gaili quo- ** que in aucupiis verbum EJfos et EJfircs adhibcnt) detexit, ac liandrorum colonias in iis rc- " licjuit, undc et infulas illx Flandria; vocari caperunt, &c." Quoique ce monument foit con- traire a I'opinion gcneralement re^uc que les Acores ont ete decouvertes ptir un Portugais nomme Gonzalve Velho, on ne fnuioit Jouter de fon autlienticite ; il fe trouye confirme jiar plufieurs auteurs contemporains, et furtout par Wagenfeil, un des plus grands favaiis du dernier fiecle, qui apres avoir voyage par I'Afrique et par toute I'Europe, a etc fait dodteur en droit a Orleans, et academicien a Turin et a Padoue quoiqu'il fut ne Allemand. On en trouve des details dans fon hiftoirc univerfelle et dans fa geographic. On m'a d'ailleurs communique dans les archives de Nurenberg une note en AUemand ecrite fur parchemin, contenant les faits fuivans : " M. Martin Beiiam, ecuyer, fils de ]VI. Martin Eeham de Scopperin, a vecu fous le *' regne de Jean 11. roi de Portugal, dans une ille qu'il a trouvce lui meme, et qu'il a appellee " iile de Fayal; elle eft fituee aux Acores dans I'occan occidental." Apres avoir obtenu de la regeute Ifabelle la proprictc de fayal, et apres y avoir employe en- viron DISCOVERY OF AMERICA. 269 which time he was huficd in making frefh difcovcries in geography, by fmall excurfions, which need not be men- tioned, Behem appHed in 1484 (which was eight years before Cohnnbus's expedition) to John II. king of Portu- gal, to procure the means of undertaking a great expedi- tion towards the foulh-weft. This prince gave him fome fhips, with which he difcovered that part of America, which is now called Brazil ; and he even failed to the freights of Magellan, or to the country of fome favage tribes, whom he called Patagonians, from the extremities of their bodies being covered with a fkin more like a bear's paws than human hands and feet. This fail is proved by authentic records, preferved in the archives of Nurenberg. One of which in particular deferves attention " Martin " Behem, traverfing the Atlantic ocean tor feveral years, " examined the American iflands, and difcovered the " ftrait which bears the name of Magellan, before either *' Chriftopher Columbus or Magellan failed thofe feas; *' and even mathematically delineated on a geographical *' chart for the king of Lufitania, the fituation of the *' coaft, around every part of that famous and renowned *' ftrait." This afTertion is fupported by Behem's own letters, written in German and preferved in the archives of Nurenberg, in a book which contains the birth and il- luftrious adtions of the nobility of that city. Thefe let- M m ters tiron 20 annees a faire des recherches ulterlcures fur la geographic, dans de petites excurfions rla alium ** orbem JmBmui m'o'u itiai^rM-un: ^nt multisannis a nuUis quam a 'Jar.:i£rf:bus licet ft ufira tentatum; " perafta autem hujurniodi navigatione viciffiaio fexto meufe reverii funt ia Portugalliam, •' plurjbiis ob acris impatientiam mortuis." Cequi DTSCOVEP.Y OF AMERICA. 271 This paflage becomes more interefting, from being quoted in a book on the ftate of Europe during the reign of the emperor Frederick III. by the learned hiftorian iEneas Sylvius, afterwards pope Pius II. This hiftorian died before the difcoveries of Behem v.'ere made, but the publilhers of his works, thougl.t the paflage in Hartman Schedl fo important, that they inferted it in the hiftory. We alfo find the following particulars, in the remarks made by Petrus Mataius, on the canon law, two years be- fore the expedition of Columbus: " The firft chriftiaii " voyages to the newly difcovercd illands became fre- *' quent, under the reign of Henry fon of John king of *' Lufitania. After his death, Alphonfus the fifth profecut- *' ed the defign, and lohn who fiicceeded him followed " the plan of Alphonfus by the aififtance of Martin Bochm, - *' a very experienced navigator, fo that, in a fliort time, *' the name of Lufitania become famous over the whole *' world." Cellarius, one of the moft learned men of his age, fays exprefsly : " Bcehm did not think it enough to *' furvey the ifland of Fayal, which he firft difcovered, or " the other adjacent iflands which the Lufitanians call *' Azores, and lue after the exa7nple of BxhnC^ companions^ *' call Flemiflj iflands; but advanced ftill farther and far- *' ther fouth, until he arrived at the remoteft ftrait, be- *' yond which, Ferdinand Magellan, following his tradt, *' afterwards failed and called it after his own name." M m 2 All Ce qui rend ce pafTage plus interelTant encore, c'eft qu'il efl: cite dans I'ouvrage du favant hif- torien JEneas Sylvius^ dcpuis pape fous le noni de Pie II. fur I'cut de I'Europe du terns dc I'empereur Frederic III. Cct hirtorien eft niort avant les decouvertes de Bchcm, ma?s I.rr, copiftes de I'ouvrage d'yEntas Sylvius ont trouvc le paffage dc Hartman Schedl li intcrtflant tju'ils Tont infcrc dans le cori)5dc cette hiftoirc. Nous trnuvons d'aillcurs dans Ic-s note que Petrus Mata;i a faitcs fur le droit canon, deux ans avant I'expedition dc Colomb, les details Tuivans : " Prima; navinationes chriflianae ad novas infulas eluccfcerc csperunt fub Henrico ** Johannis Lufitanis re^is filio, &:c. illo mortuo Alphonfus V. crepta profccutus eft ; Al- ** phonfum Johannes Imitatus opera Alartin: Bo/jirf/.-:^ hominis in curfu navium pcritilnmi, ut ** brevi tempore nihil celebrius per totum orbem audiretur ipfo Lufitania nomine." Cel- larius, un des plus grands lavans de ion fiecle, dit expreficnicnt : " Behaimius non modo '* Fagalem infulam, quam primus iiivenit, aut alias circumjec^las quas Azores Lufitani, nos *' Flatidriczs a Behaimi comitibus^ nominant, perluftrandas libi cenfuit, verum etiam in auftrum *' maejis ft magis progreflus ufque ad ultimum fretum, quod Fcrdinandus Magellanus huius ■*' du(5ium fecutus, pertranfiit e; de luo id nomine appcUavit." Toutc» 272 M E M O I R ON THE All ihefe quotations, which cannot be thought tedious, fmce they ferve to prove a faie de prcfomption. Mais, dira-tou, pourquoi enlcver a Chriftophe Colomb une gloire que toute I'Europe !ui a accordee jufqu'ici ? Pourquoi chercher dans les archives d'une viUe imperiale les caufes d'un evencment qui a eu lieu a rextrcmitc la plus occidentale de I'Europe ? Pourquoi les ennemis' de Chriltophe Colomb, qui etoient en grand nombrc, n'ont 'ils pas tire parti des pretendues decouvertes du Chevalier Behem pour diminuer ion importance a la cour d'Efpao-ne ? Pour- quoi le Portugal, jaloux de la decouvertc du nouveau nioude, n'at'il pas protefte centre Ics aflertions des Efpagnols ? Pourquoi Behem qui n'cft mort qu'en 1506, n'at'il pas laifte lui meme a la pofterite un ecrit pour s'attribuer une decouverte aufti importante ? Pour repondi'e a toutes ces tjueftions je foumettrai au leiili;ur impartial les remarqucs fuivantes : I. Avant 28o M E M O I R ON THE 1. Before Columbus, the great merit of a navigator confifled rather in conceiving the poffibiHty of the exift- ence of a new continent, than in fearching for lands in a region where he was fure to find them. If it is then cer- tain that Behem had conceived this bold idea before Co- lumbus, the fame of the latter muft be confiderably di- miniihed, 2. The hiftorical proofs, which we have given above> leaving us no doubt of the fa£l, we have only to explain the moral caufes of the filence of the Spanifh and Portu- guefe authors, of the enemies of Columbus, and of Behem himfelf. 3. It is well known, that previous to the reign of Charles V. there was little communication between the learned men of different nations. Writers were fcarce, excepting fome monks who have related, well or ill, the events which came to their knowledge, in chronicles which are no longer read; or they had but little idea of w^hat pafled in foreign countries. Gazettes and journals were unknown, and the learned obliged to travel to in- form themfelves of the progrefs of their neighbours. Ita- ly was the center of the arts and what are called fcience at that time. The frequent journies of the German em- perors to Rome gave them an opportunity of knowing perfons of merit, and of placing them in the different uni- verfitles of the empire, it is to this circumftance that we ought 1. Avant Colomb le grand mcrite d'un navigateur confidoit plutot a con5evoir la poiTibilite de I'exiP^t'nce d'un nouvcau continent, qu'a chcrcher dcs terres dans une region ou il etoit fur d'en trouver. S'il eft done certain que Behcni a eu cette idee hardie avant Colomb, la gloire de ce dernier en efl; fmgulierement diminucc. 2. Toutes les preuves hiftoriqucs que nous avous donnc's ci deffus ne nous laiffant aucun doute fur le fait, il s'agit feulement d'expliquer les caufes morales du filence des auteurs Efpagr.oU et Portugais, des ennemis de Colomb, et de Beliem lui-meme. ■;. On fait qu'^vant Charles quint il y avoit tres peu de communication cnlre les favans des diflerentes nations. Les ecrivains etoient fort rarcs, a I'exception de quelques mcines qui ont rapportc bien ou mal les evenemens qui etoient a Icur portce dans des chroniqiies qu'on ne lit plus, ou n'avoit que peu de notions iiir ce qui fe paffoit en pays etranger ; les gazettes, les journaux etoint inconnus, et les favans etoient obliges de voyager pour voir de leurs pro- pres yeux les progres de leurs voifms. L'ltalie etoit le centre des arts et de ce qu'on apptlloit fcience dans ce tems-la. Les frequens voyages dcs empercurs d'Allemagne a Rome Icur don- na la Lvilite de connoitre des gens de mcrite, et de les placer dans les differentes univerCtcs de DISCOVERY OF AMERICA. 281 ought to attribute the great progrefs which the Germans made, particularly in mathematics, from the fourteenth to the lixteenth century; during which time they had the bed geographers, the beft hiPtorians, and the moft en- lightened politicians. They were particularly attentive to what paifed in Europe, and the multiplied connexions of different princes with foreign powers, affifted them great- ly in colledting in their archives the original pieces of the moft important events of Europe. It is to this fpirit of criticilm and enquiry, that we are indebted for the refor- mation of Luther, and we cannot deny, that particularly m the fifteenth century, there was more hiftorical and political knovv'ledge in Germ.any than in all the reft of Europe, Italy excepted. It is not then aftoniftiing, that we fhould find, in the archives of one of the moft ancient imperial cities, the particulars of an expedition, planned upon the banks of the Tagus by a German, a man of great repute in his own country, and whofe every aftlon became very interefting. 4. It was different in Portugal, where the whole nati- on, except the king, was plunged in the moft profound ignorance. Every body was either fhopkeeper, failor or foldier; and if this nation has made the moft important difcoveries, we muft afcribe them rather to avarice than to a defire of knowledge. They were fatisfied with fcrap- ing de Tempire. C'efl: a ccttc circonllance que Ton dolt attribuer les grands progres que les Al- Icir.ans ont faits furtout dans Ics mathematiqnes, dcpuis ie XIV. juiqu'au XV!. fiecle; ils avoient les meilleurs geographcs, les meilleurs hiftoriens et les politiques les plus cclaires, lis etoicnt attentifs fur tout ce qui fc paffoit en Europe, et les liaifons muUipliees des diffe- rens princes nvec les puIfTances ctrangercs, leur donnoient unc grande facilite de raflembler, , dans leurs archives, les pieces originales de'^ evcnemens les plus importans de TEuropc. C'efl a.cet cfprit dc critique et de recherclie qu'eft due en grande partie la reformation de I.uther, et on ne pent fe dUlimuler, que, furtout dsnsle XV. fieclc, il n'y.^it eu plus de connoifTances hi.n;oriqucs et politiques en Allemagne que dans tout le refte de TEurope, a I'exception de ritalie. II n'efl: done pas ctonnant que nous trouvions dans les archives d'une des plus anci- ennes villes imperiales des details fur une expedition, projettt fur les bords du Tage par uii AUcmand. par un homme tres confiderc dans fon pays, et dont parcr.nfcquent toutes les de- marches deviiioient interclTantes. 4. II n'en etoit p;is de meme du Portugal, oil toutc la nation a. I'exception du fouvcrain, ctoit plongc-c dans la plus prcfonde ignorance. Tout Ic monde y etoit ou marchand, ou nia- telot, ou foldat; et fi cc peuplc a fait les decouvertes les plus impnrtantcs, il faut en cherchcr le motif dans fa cupidite, et non dans fon defir dc s'iiiflruirc. li fc contenta d'amaffer dc I'or 282 MEMOIR ON THE ing together gold in every quarter of the known world, whilft the German and the Italian took up the pen, to tranlmit to pofterity the remembrance of their riches and cruelties. The Spaniards were not much more informed before Charles V. introduced at Madrid the learned men of Flanders and Germany. It is then very poffible, that the chevr. Behem made very interefting diicoveries in geography, in 1485, without the public's being acquaint- ed with them. If he had brought back from his expedi- tion, gold or diamonds, the noil'e would have been fpread in a few weeks; but fimple geographical knowledge was not of a nature to intereft men of this turn of mind. 5. The long ftay which Chriftopher Columbus made at Madeira, makes his interview with Behem more than probable. It is impofTible that he fhould have negledted feeing a man fo intereiling, and who could give him every kind of information, for the execution of the plan which he had formed. The mariners who accompanied the chevr. Behem, might alfo have fpread reports at Madeira and the Azores, concerning the difcovery which they had been witnefl'es of. What ought to confirm us in this, is, that Mariana fays himfelf (book 26. chap. III.) that a cer~ tain vefld going to Africa, was thrown by a gale of wind upon certain unknown lands, and that the failors at their return to Madeira had communicated to Chriftopher Co- lumbus dans toutes les parties du monde connu, tDndifque rAllematid ct I'ltalien tcnoient la plume pour tranfmtttre a la pofterite le fouvcnir dc les richelTes et de fes cruautes. l^es Elpagnols u'ctolent par beaucoup plus inftruits, avant que Charlcsquint eut amenc a Madrid des lavans de Flandres et d'AUemagne. II eft done trcs poffible que le chevalier Behem ait fait en 1485, des decouvertes tres intereflantes pour la geographie, fans que le public en ait ete in- ftruit. S'il eut rapporte de fon expedition de Tor ou des diamans, le bruit s'en leroit repandu en peu de femaines, mais de fiinples notions geographiques n'ctoient pas de nature a interef- fer des hommes de cette trempe. 5. Le long fiiour qu'a fait Chriftophe Colomb a Madere, rend fon cntrcvue avec Behem plus que vraifeniblable. 11 eft impoQible qu'il ait neglige de voir un Iiomme aulTi intereftant, et qui pouvoit lui donner toutes fortes de confeils fur I'execution du plan qu'il avoit forme. Les marins qui ont acconipagne le chevalier Behem pouvoient d'ailleurs repandre a Madere', et aux Azores, des bruits concernant les decouvertes dont ils avoient etc temoins. Ce qui doit nous confirmer dans cette opinion, c'eft que Mariana dit lui-meme (livre 26. chap. .3.) qu'un ceitaht batiment allant en Afrique, avoit ete jette par un coup de vent fur de certaines terres inconnues ; et que les matelots apres leur retour a Madexc, avoient commiinique i Chriftophe DISCOVERY OF AMERICA. 28^ Fumbus the circumftances of their voyage. All authors agree that this learned man had ibme information refpedting the weftern fliores, but they fpeak in a very vague man- ner. The expedition of the chevr. Behem explains this, myftery. 6. This aftronomer could not be jealous of the difco- veries of Columbus, becaufe the laft had been farther north, and that in a time when they did not know the whole extent of the new world, and when geographical knowledge was extremely bounded, it might be believed, that the country difcovered by Columbus, had no connec- tion with that difcovered by Behem. It appears however, certain, that Behem difcovered this continent before Columbus, and that this queflion, which is only curious in Europe, becomes ioterefting to the American patriot. The Grecians have carefully preferv- ed the fabulous hiftory of their firft founders, and have raifed altars to them; why are not Behem, Chriftopher Columbus and Vefpucius, deferving of ftatues, in the public fquares of American cities ? Thefe precious monu- ments would tranfmit to pofterity the gratitude which the names of thefe benefadlors of mankind fliould infpire. Without knowing it, they have laid the foundation of the happlnefs of many millions of inhabitants; and Sefoftris, Phul, Cyrus, Thefeus and Romulus, the founders of the greateft'. Chriftophe Colonib les circonftances de leur navigation. Tous les auteurs s'accordent en. gijiicral, que ce favant avoit eu quelques renfcip;ncniens fur des tcrrcs occidentalos, niais ils Hc nous en parlent que d'uue maniere tres vague. L'expcdition du chevalier Beliem nous cxplique ce niyllere. 6. Cet aftronome ne pouvoit ctre jaloux des dccouvertes de Cotomb, puifque celui-ci a. ete beaucoup. plusnord ; et que dand un tenis oii i'on ne connoifloit par toute I'etendue du iTouveau nionde, et oil les comioifTances gcog;raphiques etoient extrememcnt bomees, ou pou- voit croire que le pays trouve par Colomb n'avoit aucun rapport avec celui de Behem. Quoiqu'il en foit, il paroit certain que Behem a decouvert ce continent avant Colonib et que cettc queftion qui n'eft que de pure curiofite en Europe, devient intereffante pour le pa- triote Amei-icain. Les Grccs ont conferve folgneufcnient riiilloirc fabuleufe de leurs pre- mieres foiidateurs, ils leur ont eleve des autcls ; pourquoi Behem, Chriftophe Colomb et Vefpuce ne meriteroicnt'-ils pas des ftatues fur les places publiques des viUcs Americaine? ? Oes monumens precieux tranfmettroient a la pofterite la reconnoilTance que doivent infpircr les noms de ccs bienfaiteurs du genre Kuniain. Sans le favoir ils ont jette les fondemcns du bonheur d= pluCcurs millions d''habit=ns ; et Sefofliis, Phul, Cyrus, Thefce, Romulus, Ks focdateurs ■ 284 Of vegetable ACID and greateft empires, will be forgotten, before the fervices ren- dered by thele illuftrious navigators can be effaced from the memory of man. fondateurs des plus grands empires, feront oublies, avant que les fervices rendus par ces na- viguteurs illuftres, puiffent s'effacer de la memuire des homir.es. N° XXXVI. The antlfeptic Virtues of Vegetable Acid and Marine Salt combined., in -various DiJ'orders accompanied ivith Pu- tridity ; communicated in a Letter to John Morgan, M. D. F. R. S. and Profejfor of the Theory and Pra^ice of Phyfic at Philadelphia, by William Wright, M. D. ofTrelaxvney in "Jamaica. HAVING experienced the virtues of vegetable acid and marine fait, when combined ; I beg leave to lay before you a few obfervations on the ufe of this iimple medicine in feveral difeafes. It is my fincere wifh, that it may prove as beneficial to mankind in general, as it has been to many of my patients in this part of the country. Take of lime-juice or lemon-juice three ounces, of ma- rine fait as much as the acid will diflblve ; of any fimple diftilled cordial water one pint ; and of loaf fugar a fuf- ficient quantity to fweeten it. The dofe of this mixture muft be proportioned to the age, fex, and violence of the difeafe. A wine glafs-ful may be given to adults every two, four or fix hours. By GeofTroy's table it appears, that the foffil alkali has a greater affinity with the marine, than with the vegeta- ble acid. However, marine fait diffolves readily in the lime-juice, throws up a white fcum to the furface, and on applying the ear near the veffel where the experiment is made, a fmall hiffing may be heard, fimilar to that when acids MARINE SALT. 285 ticids and alkalies are mixed. It would feem probable that part of the marine fait is hereby decompofed. That vegetable acids and marine fait are antifeptics, has long been known, but their etfefts when mixed I appre- hend to be but lately difcovered. Without farther preface, I fliall proceed to the particu- lar difeafes in which they have been adminiftered, pre- pared as above. Of the dysentery. The dyfentery is a very frequent diforder in this and other Weft-India iflands; and fometimes is epidemic, par- ticularly in the rainy feafons, or when provifions are fcarce. Amongft other cauies of dyfenteries, 1 have often known the eating of yams not arrived at maturity, as alio unripe alligator pears, produce a bloody flux. Dyfenteries commonly begin with frequent loofc ftools for a day or two, attended with gripings : by degrees, the gripes grow more Tevere, nothing is voided by ftool but a fmall quantity of mucus, mixed with blood ; a tenefmus comes on and is exceedingly troublefome. The appetite fails, the patients are low fpirited, and fuf- fer a great proftration of ftrength. The mouth and tongue are much furred and flimy, and the tafte is like that of rotten butchers meat. The defire of drink is fometimes excefTive, but for the moft part very moderate. The pulfe is very low, feeble and undulating; and rarely rifes fo high, as to indicate the ufe of a lancet. Such was the dyfentery in 177 1. It proved fatal to many people, both old and young, though treated according to the moft ap- proved methods of cure, and the lofs of feveral patients of mine, convinced me of the neceflity of ufing antifep- tics early in this difeafe. A vomit feemed neceflary to clear the ftomach, and fome gentle purge, to carry off part of the offending mar- O o ter 286 Of vegetable ACID and- ter by ftooL But the adion of thefe, however mild, often increafed the proftration of ftrength, and rendered the ftools fooner bloody. Nor was opium of any real ufe. A tea made of Simarouba and given to fome, had a very falutary efled:, whilft, if given to others, it would by no means lye on their ftomachs. From a confideration of the antlfeptic quality of both the fal: marin: and of the vegetable acid, I was induced to make trial of their effeds united in the manner above mention- ed. It a£ted like a charm, and I find that from the ufe of it, the frequency of ftools, gripes and tenefmus, have foon worn off; the ftools gradually become of a natural confiftenceand quantity; the fpirits, ftrength and appetite returned, and the patient has been reftored to perfedl health in a very few days. When the dyfentery was of long ftanding, ftarch cly- fters, with a fmall portion of opium, abated the tenefmus.. This medicine was equally ferviceable in diarrhoeas.. DIABETES. As I had fucceeded fo well in the cure of dyfenteries, I was determined to try its eftedls in the diabetes : fe- veral opportunities foon offered ; but as thefe cafes were accompanied with other complaints, efpecially with fevers of the remitting kind, it will be proper firft to Ipeak of The remittent FEVER. This by far the moft common fever within the tropics, is the leaft underftood, and conlequently for the moft part badly treated. Strangers, who walk much, or work hard in the heat of the fun, are more fubjedl to it than feafon- ed Europeans or natives of the country. Dr. Cleghorn's defcription of this fever is accurate and juft. His method of cure, funple and eafy. Every phy- fician MARINE SALT. 287 ficlan, who would wifh to pradllce with fuccefs, fliould be well acquainted with that valuable performance, as alio with what Dr. Lind has laid on the fubjeft. It is then fufficient here, to obferve that remittent fevers are often attended with diarrhoeas, the diabetes, and fome- times with a copious difcharge of faliva, as if mercury had been previoufly given. In fuch circumftances I ne- ver found the bark of fervice; a few glafl'es of the above mixture fully anfwered the intention, not only by re- moving thefe fymptoms, but the fever at the fame time. The Peruvian bark afterwards, taken out of fome of the fame mixture, effecStually fecured the patient from a re- turn of this dangerous malady. The mixture rarely adted as an aftringent in this or any other diforder. But when this effedl took place, the in- terpofition of fome lenient purge was deemed neceffary. BELLY-AC H. The belly-ach with inflammatory fymptoms has fre- quently occured in the courfe of my practice ; they yield- ed with difficulty to bleeding, fmall dofes of emetic tar- tar, a mercurial pill, repeated dofes of caftor oil, diluting drinks, with nitre, fomentations and glyfters. A copious difcharge of foetid excrement for the moil part gives im- mediate relief. I have obferved in many cafes, after mofl: excruciating belly-achs, that the ftools were liquid, white, fmall in quantity, and very foetid. The patients being worn out with pain, grew difpondent, did not care to fpeak, fell into cold clammy fweats and were very rel^lefs. They complained of an ill tafte in their mouths. Their tongues were much furred. Their breath offenfive, and they had a great propenfity to vomit. Formerly I attempted the relief of thofe threatening fymptoms with the bark, in various forms, as well as O o 2 claret. 288 Of vegetable ACID and claret, and often faved my patient ; fometimes however I failed of fuccefs. When fuch cafes fall now under my care, I have immediate recourfe to the antifeptic mixture j nor have I been hitherto difappointed : the ftools becom- ing lefs frequent on the ufe of it, and of a better confift- ence ; the cold fweats alfo dlfappear, and the fpirits foon return, together with an appetite for food. The putrid SORE THROAT. In June 1 770, the putrid fore throat made confiderable havock amoneit adults and children. It attacked thofe of a lax habit, who for a few days had flight head-achs, chillinefs and heats alternately, and an uneafinefs about their throats, but not fo much as to hinder their fwal- lowing. On examination, the mouth, tongue and gums were foul and flimy ; the tonfils and uvula covered with white fpecks or (loughs ; the breath was hot and offenfive ; the fkin felt hot and pungent to the touch; the pulfe low and quick ; a diarrhoea often attended, and the patients were in general much dejedted. Antimonial wine with cordials and nourlfhing diet fuc- ceeded beft, till the floughs or fpots were removed and feparated ; then the bark completed the cure. When a diarrhoea accompanied this diforder, I gave the mixture with fuccefs. In all diforders where a gargle is neceffary, I make ufe of the above mixture in preference to any other ; and I find It fpeedily cleanfes the tongue, gums and fauces, and fweetens the breath. Where lemons or limes cannot be had, vinegar or cremor tartar may be fubftituted In their room. From what has been fiid, it is evident, that the medi- cine is poflelTed of confiderable antifeptic powers, and its virtue MARINE SALT. 289^ •slrtue confifls in correding the peccant matter In the Ito- mach and inteftinal canal. All the dileafcs in which I have given it, had a putrid tendency. I ihall be happy to hear of its fuccefs in your weftern hemilphere. And am, with efteem, Si r. Your moft humble fervant, WILLIAM WRIGHT. N° XXXVIL Medical Hljlory of the Cortex Ruber, or Red Bark ; coni- iuunicated /«? John Morgan, M. D. Profeffhr of the Theory and Pra£lice of Phyfic at Philadelphia., and F. R. S. London, i^-c. ^^'^1^34' T HAVE lately received the following commu- J_ nications upon the Cortex Ruber, which I have found fo efficacious in the cure of obftinate remittent and bilious fevers, that I think it my duty to lay them before this fociety, in hopes of fo valuable a medicine being thereby better known, and introduced more generally in- to pradtice.. Extra^ of a Letter from Thomas S. Duche, dated Lon^ don, Augujl 9, 1783.. " I was lately at a ledlure delivered at Guy's hofpital, by Dr. Saunders, upon the cure of intermittent fevers, and obferving the doQor fpoke very much in favour of a new fpecies of bark which he had introduced into the praif^ice of phyfic, I procured a fpecimen of it for you, thinking 290 MEDICAL HISTORY of the thinking it might be agreeable to you to hear of any new improvements in the heaUng art. It is called Red Bark. According to his account it poffeffes fo much virtue, and is of fuch certain efficacy, that, compared with it, the com- mon bark is an inert mafs. It contains a much larger portion of refin, has a much ftronger aromatic tafte than the common bark, and does not require half the quantity for a dofe. Amongft other particulars, he mentioned the following proof of its fuperior virtue, namely, that of this medicine, when adminiftered in a fimple cold infufion, any given quantity is much ftronger and effectual to re- move the fever than a chemical extraft from the fame quantity of the other. I now fend you a fpecimen, by which you will be able to make a trial and form fome judgment of its virtues." ^ T. S. DUCHE. Soon after the receipt of the foregoing letter, I received the following valuable communication from Dr. George Davidfon of St. Lucia, which it affords me great pleafure to lay before this fociety. St. Lucia, Auguft 29, 1783. To Dodor John Morgan, at Philadelphia. Sir, IF the fubje£l upon which I have the honour to write you, fliould be found to merit attention, and prove in any reiped; ufeful and advantageous to mankind, I fliall eafily ftand excufed in addreffing you, perlbnally unacquainted as I am. I have by this opportunity fent a fmall fpecimen of the Cinchona of this iflaud, refembling the Peruvian bark in its botanical character, and from the trial made here fur- paffing it in medical virtues. It is now nearly four years lince the Caribaean bark was difcovered upon the heights adjoining CORTEX RUBER, or RED BARK. 291 adjoining Morne Fortune, and introduced into pradice by Dr. Young, phyrici4n to his Britannic majefty's troops. The freflinefs of the bark, the little attention beftowed in drying it, and the large doles in which it was exhibited, produced alarming fits of vomiting and purging, and de- terred us, at that time, from the further profecution of the fubjed, until the other day that a treatife upon the red bark, by Dr. Saunders of London, and a belief which we entertained that this was the fame bark which he delcribes, induced us again to make a trial of it. Having properly dried it, and given it in the cold infufion with greater caution and in lefs dofes than at the firft eflay, we are now happy in alluring the public, that in moft inftances it has not diilippointed us. Still, however, notwithftanding the utmoft care in drying it, in fome cafes it ftill feems to re- tain its emetic and purgative qualities, as the flomach and fu-ft paflages, in complaints here, are loaded with a quan- tity of putrid bile. Thefe are not its leaft valuable pro* perties. It will, however, be neceflary when thefe effefts are produced, to check them afterwards by opiates. With regard to its preparations: I have generally given it in the cold infufion either made with lime or cinnamon water. An extract made with fpirits and water fits eafi- ly on the ftomach and can be given in larger quantities. In fome late cafes of tertians, where I have been cal- led to the patient during the fecond fit ; without watch- ing for its going off, 1 have begun with this bark, which effedlually cleanfed the ftomach and bowels, and paved the way for its future adminiilration. In putrid dyfenteries, and in a remarkable fpecies of dyfentery, conjoined with an intermittent fever, which I have met with here, the bark has done more than all the remedies which I have feen employed. The purgative eftetfts which it produced enabled us to throw it in earli- er; the hardened fcybula, the fupport of the difeafe, were removed 292 MEDICAL HISTORY of the removed, the ftomach and bowels braced up, and, by the interpofition of opiates, the fpafms were removed. Having fent feveral fpecimens of the bark for a trial to different parts of the continent of America, and parti- cularly to my worthy friend Dodor Hall of Peterfburgh Virginia, I impatiently wait the refult of your trials, and will efteem myfelf particularly obliged by your commu- nication. If you chufe, I (hall fend you fome of the young trees planted in tubs, with fome of the feeds. Should it be found to anfwer my expe£lation, the plea- fure refulting from the thoughts of havirig communicat- ed fomething ufeful, will be to me ample enough recom- penfe. I have the honor to be. With the utmoft refpeft. Your moft obedient humble fervant, GEORGE DAVIDSON. P. S. Dr. Wright of Jamaica (in fifth vol. of medical commentaries,) defcribes a fpecies of Cinchona, with only one flower on a footftalk; the fame was likewife found at the Havanna. It differs in that particular from the old bark, which refembles the St. Lucia bark, in having feve- ral flowers on each footftalk. The folloiv'ing is a Defcription of the Cinchona Cari- BJEA SaNCTJE LuCI^. The tree is commonly found in ravines, near fprings, under the fliade of a larger tree. It delights in places well fliaded, and defended from the north-eart trade wind. The foil is commonly a ftiff red earth with a clayey fub- ftratum ; quantities of fmall beautiful chryllals, of a regu- lar angular form, are found intermixed. The tree is about the fize of the cherry tree ; feldom exceeding the thicknefs of the thigh, and twenty-five feet in height. The CORTEX RUBER, or RED BARIL 293 The flowers begin to appear at the commencement of the rainy feafon in beautiful tufts, upon pannicles branch- ed out in threes and fours. I have never feen that fpecies defcribed by Jacquin and found at the Havannah, pedun- culis uniflons. Before the corolla is fully expanded, and the ftamina make their appearance without the tube of the corolla, the flower is white, but it afterwards turns to a beautiful purple. Then dropping ofl-\ the germen enlarges to the llze of an hazle-nut, oblong and round. It gradually dries, burlls in two, and fcatters the feeds, which fall to the ground and again take root. The wood of the tree is light, fpongy, and fit for no ufeful purpofe. It has not the bitter tafte of the bark. The leaves are very bitter, and the flowers, feeds, &c. feem to poflefs the bitternefs and aftringency in a more eminent degree. An ounce of the bark in fine powder infufed in a quart of cold water for twenty-four hours, and the infufion af- terwards filtered, appears higher coloured than a decoction made with double the quantity of the old bark. The co- lour which it ftrikes with the tin^. Jlor. martial, and J'al fnartis, is likewife of a deeper black. The fpirituous tincture is of a deep red colour, and ftrikes a deep black by the addition of the preparations of iron. The tafte of the Cinchona Caribsea is manifeftly more aftringent than the tafte of the old bark ; an inference may therefore, ^ priori, be made, that its tonic powers are greater. The quantity of refin which it yields is much more confiderable, and an extradl made with both fpirits and ■water, feems to poflefs the whole virtues of the bark. Pp To [ 294 I N° XXXVIII. A Letter from Dr. Benjamin Franklin, to Mr. Al- PHONSUS le Roy, Member of fc'vernl Academies^ at Paris. Containing fiuidry Maritime Obfervations. At Sea, on board the London Packet, Capt. Truxton, Auguft 1785. SIR, Read nee. "'CT" O U R learned writings on the navigation of 2, 1785- Jl^ (.j^g antients, which contain a great deal of curious information; and your very ingenious contrivances for improving the modern fails [iioilure) of which I faw with great pleafure a fuccefsful trial on the river Seine, have induced me to fubmit to your confideration and judgment, fome thoughts I have had on the latter fubjedt. Thofe mathematicians who have endeavoured to im- prove the fwiftnefs of veffels, by calculating to find the form of lead refiftance, feem to have confidered a fhip as a body moving through one fluid only, the water; and to have given little attention to the circumftance of her movinrr through another fluid, the air. It is true that when a veflel fails right before the wind, this circumftance is of no importance, becaufe the wind goes with her; but in every deviation from that courfe, the refiftance of the air is fomething, and becomes greater in proportion as that deviation increafes. I wave at prefent the confidera- tion of thofe diff'erent degrees of refiftance given by the air to that part of the hull which is above water, and con- fine myfelf to that given to the fails; for their motion throuuh the air is refifted by the air, as the motion of the hull through the water is refifted by the water, though with lefs force as the air is a lighter fluid. And to fim- plify the difcuflion as much, as polfible, I would ftate one Situation only, to wit, that of the wind upon the beam, thefliip's courfe being diredly acrofs the wind; and I would fuppofe MARITIME OBSERVATIONS. 295 fuppofe the fail fet in an angle of 45 degrees with the keel, as in the following figure ; wherein AB reprefents the hody of the veffel, CD the pj:",'^!. pofition of the fail, EEE the diredtion of the " • wind, MM the line of motion. In obferving this figure it will appear, that fo much of the body of the veiiel as is immerfed in the water, mufl, to go forward, remove out of its way what water it meets with between the pricked lines FF. And the fail, to go forward, muft move out of its way all the air its whole dimenfion meets with between the pricked lines CO and DO. Thus both the fluids give refiftance to the motion, each in proportion to the quantity of matter contained in the dimenfion to be removed. And though the air is vaftly lighter than the water, and there- fore more eafily removed, yet the dimenfion being much greater its effedt is very confiderable. It is true that in the cafe llated, the refiftance given by the air between thofe lines to the motion of the fail is not apparent to the eye, becaufe the greater force of the wind which ftrikes it in the dired:ion EEE, overpowers its cfFe£t, and keeps the fail full in the curve a, a, a, a, a. But fuppofe the wind to ceafe, and the veffel in a calm to be impelled with the fame fwiftnefs by oars, the fail ^vouId then appear filled in the contrary curve b, b, b, b, b, when prudent men would immediately perceive that the air refilled its motion, and would order it to be taken in. Is there any pofTible means of diminlihing this refift- ance, while the fame quantity of fail is expofed to the ac- tion of the wind, and therefore the fame force obtained from it ? I think there is, and that it may be done by di- viding the fail into a number of parts, and placing thofe parts in a line one behind the other ; thus inftead of one fall extending from C to D, figure 2, if four fails containing together the lame quantity of canvas, were placed as in figure 3, each having one quarter of the di- P p 2 menfions 296 MARITIME OBSERVATIONS. menfions of the great fail, and expofing a quarter of its furface to the viiid, would give a quarter of the force; fo that the whole force obtained from the wind would be the fame, while the refiftance from the air would be nearly reduced to the fpace between the pricked lines aba.nd cd^ before the foremoft fail. It may perhaps be doubted whether the refiftance from the air would be fo diminiihed ; fince polfibly each of the following fmall fails having alfo air before it, which muft be removed, the refiftance on the whole would be the fame. This is then a matter to be determined by experiment. I will mention one that I many years fince made with fuccefs for another purpofe; and I will propofe another fmall one eafily made. If that too fucceeds, I fhould think it worth while to make a larger, though at fome expence, on a river boat ; and perhaps time and the im- provements experience will aff'ord, may make it applicable with advantage to larger velTels. Having near my kitchen chimney a round hole of eight inches diameter, through which was a conftant fteady current of air, increafing or diminiflilng only as the fire increafed or diminifhed, I contrived to place my jack fo as to receive that current; and taking off the flyers, I fix- ed in their ftead on the fame pivot a round tin plate of near the fame diameter with the hole ; and having cut it in radial lines almort to the centre, fo as to have fix equal A'anes, I gave to each of them the obliquity of forty-fiA'e degrees. They moved round, without the weight, by the impreflion only of the current of air, but too flowly for the purpofe of roafting. I fufpeded that the air ftruck by the back of each vane might pofFibly by its refiftance re- tard the motion; and to try this, I cut each of them into two, and I placed the twelve, each having the faine obli- quity, in a line behind each other, when I perceived a great augmentation in its velocity, which encouraged me to di- vide MARITIME OBSERVATIONS. 297 vide them once more, and, continuing the fame obliquity, I placed the twenty-four behind each other in a line, when the force of the wind being the fame, and the fur- face of vane the fame, they moved round with much great- er rapidity, and perfectly anfwered my purpofe. The fecond experiment that I propofe, is, to take two playing cards of the fame dimenfions, and cut one of them tranfverfely into eight equal pieces ; then with a needle firing them upon two threads one near each end, and place them fo upon the threads that, when hung up, they may be one exadlly over the other, at a diftance equal to their breadth, each in a horizontal pofition ; and let a fmall ■weight, fuch as a bird-fhot, be hung under them, to make them fall in a ftraight line when let loofe. Sufpend alfo the whole card by threads from its four corners, Snd hang to it an equal weight, fo as to draw it downwards when let fall, its whole breadth preffing againfl: the air. Let thofe two bodies be attached, one of them to one end ot a thread a yard long, the other to the other end. Extend a twine under the ceiling of a room, and put through it at thirty inches diftance two pins bent in the form of fifh- hooks. On thefe two hooks hang the two bodies, the thread that conneds them extending parallel to the twine, which thread being cut, they muft begin to fall at the fame inftant. If they take equal time in falling to the floor, it is a proof that the refiilance of the air is in both cafes equal. If the whole card requires a longer time, it fliows that the fum of the refinances to the pieces of the cut card is not equal to the refiilance of the whole one*. This principle fo far confirmed, 1 would proceed to make a larger experiment, with a fliallop, which I would rig in this manner. AB is * The motion of the vcfill made it inconvenient to try this (iiiiple experiment, atfea, wlien the propofnl of it was written. But it has been tritd liucs we came on (hore, and fucceeded as the other. 298 MARITIME OBSERVATIONS. Fi^lfril' A B is a long boom, from which are holfted fe- ven jibs, a, b, c, d, e, f, g, each a feventh part of the whole dimenfions, and as much more as will fill the ■whole fpace when fet in an angle of forty-five degrees, fo that they may lap when going before the wind, and hold more wind when going large. Thus rigged, when go- ing right before the wind, the boom fhould be brought at right angles with the keel, by means of the flieet ropes C D, and all the fails hauled flat to the boom. Thefe pofitions of boom and fails to be varied as the wind quarters. But when the wind is on the beam, or Avhen you would turn to windward, the boom is to be hauled right fore and aft, and the fails trimmed according as the wind is more or lefs againft your courfe. It feems to me that the management of a Ihallop fo rig- ged would be very eafy, the fails being run up and down feparately, fo that more or lefs fail may be made at plea- fure ; and I imagine, that there being full as much fail expofed to the force of the wind which impells the veifel in its courfe, as if the whole were in one piece, and the refiftance of the dead air againft the forefide of the fail be- ing diminiftied, the advantage of fwiftnefs would be very confiderable ; befides that the veflel would lie nearer the wind. Since we are on the fubje£t of improvements in navi- gation, permit me to detain you a little longer with a fmall relative obfervation. Being, in one of my voyages, with ten merchant-fhips under convoy of a frigate at anchor in Torbay, waiting for a wind to go to the weft ward ; it came fair, but brought in with it a confiderable fwcll. A fignal was given for weighing, and we put to fea all to- gether; but three of the fliips left their anchors, their ca- bles parting juft as the anchors came a-peak. Our cable held, and we got up our anchor ; but the fhocks the Ihip felt before the anchor got loofe from the ground, made me refled on what might poffibly have cauied the break- ing MARITIME OBSERVATIONS. 299 ing of the other cables ; and I imagined it might be the Ihort bending of the cable juft without the haufe-hole, from a horizontal to an almoft vertical pofition, and the fudden violent jerk it receives by the rifing of the head of the ihip on the fwell of a wave while in that pofition. For example, fuppofe a veflel hove up fo as to have her head nearly over her anchor, which ftill keeps Its hold, perhaps in a tough bottom; if it were calm, the cable flill out would form nearly a perpendicular line, meafuring the diftance between the haufe-hole and the anchor ; but If there is a fwell, her head in the trough of the fea will fall below the level, and when lifted on the wave will be as rnuch above it. In the firfi: cafe the cable will hang loofe and bend perhaps as in figure 5. In the fecond cafe figure 6, the cable will be drawn ftraight with a jerk, muft fuilain the whole force of the rlfing (liip, and muft either loofen the anchor, refift the riling force of the fhip, or break. But why does it break at the haufe-hole ? Let us fuppofe it a cable of three inches diameter, and reprefented by figure 7. If this cable is to be bent round the corner A, it is evident that either the part of the triangle contained between the letters a, b, c, muft ftretch confider- ably, and thofe moft that are neareft the furface ; or that the parts between d, e, f, muft be com prefixed ; or both, w'hich moft probably happens. In this cafe the lower half of the thicknefs aff'ords no ftrength againft the jerk, it not being ftrained, the upper half bears the whole, and the yarns near the upper furface belns; firft and moft ftrained, break firft, and the next yarns follow ; for in this bent fituation they cannot bear the ftrain all together, and each contribute its ftrength to the whole, as they do when the cable is ftrained in a ftraight line. To remedy this, methinks it would be well to have a kind of large pulley wheel, fixed in the haule-hole, fup- pofe of two feet diameter, over which the cable might pals ; and being there bent gradually to the round of the wheel,. 300 MARITIME OBSERVATIONS. wheel, would thereby be more equally ftrained, and better able to bear the jerk, which may fave the anchor, and by that means in the courfe of the voyage may happen to fave the fhip. One maritime obfervation more fhall finifti this letter. I have been a reader of news-papers now near leventy years, and I think few years pafs without an accoimt of fome vefl'el met with at fea, with no foul living on board, and fo many feet of water in her hold, which veffel has neverthelefs been faved and brought into port : and when not met with at fea, fuch forfaken vefTels have often come afhore on fome coaft. The crews who have taken to their boats and thus abandoned fuch veflels, are fometimes met with and taken up at fea by other fhips, fometimes reach a coaft, and are fometimes never heard of. Thofe that give an account of quitting their vefTels, generally fay, that flie fprung a leak, that they pumped for fome time, that the water continued to rife upon them, and that defpairing to fave her, they had quitted her left they ftiould go down with her. It feems by the event that this fear was not always well founded, and I have endeavoured to guefs at the reafon of the people's too hafty difcouragement. When a veflel fprings a leak near her bottom, the wa- ter enters with all the force given by the weight of the column of water, without, which force is in proportion to the difference of level between the water without and that within. It enters therefore with more force at firft, and in greater quantity, than it can afterwards when the water within is higher. The bottom of the veffel too is nar- rower, fo that the fame quantity of water coming into that narrow part, rifes fafter than when the fpace for it to flow in is larger. This helps to terrify. But as the quantity entering is lefs and lefs as the furfaces without and within become more nearly equal in height, the pumps that could not keep the v ater from rifing at firft, might af- terwards be able to prevent its rifing hi^^her, and the people might MARITIME OBSERVATIONS. 301 might have remained on board in fafety, without hazard- ing themfelves in an open boat on the wide ocean. (Fig. 8.) Befides the greater equahty in the height of the two furfaces, there may fometimes be other caules that retard the farther fmking of a leaky veflel. The rifing water within may arrive at quantities of light wooden work, empty cherts, and particularly empty water cafks, which if fixed fo as not to float themfelves may help to fuftain her. Many bodies which compofe a fhip's cargo may be fpecifically lighter than water, all thefe when out of wa- ter are an additional weight to that of the fhip, and fhe is in proportion prefl'ed deeper into the water; but as foon as thefe bodies are immerfed, they weigh no longer on the fliip, but on the contrary, if fixed, they help to fupport her, in proportion as they are fpecifically lighter than the water. And it fhould be remembered, that the largeit body of a fhip may be fo balanced in the water, that an ounce lefs or more of weight may leave her at the furface or fink her to the bottom. There are alfo certain heavy car- goes, that when the water gets at them are continually dirtblving, and thereby lightening the veUel, fuch as fait and fugar. And as to water cafks mentioned above, fince the quantity of them muft be great in fhips of war where the number of men confume a great deal of water every day, if it had been made a conftant rule to bung them up as fart as they were emptied, and to difpofe the empty cafks in proper fituations, I am perfuaded that many fhips which have been funk in engagements, or have gone down afterwards, might with the unhappy people have been faved ; as well as many of thofe which in the laft war foundered, and were never heard of. While on this to- pic of finking, one cannot help recolle£ling the well known pra£lice of the Chinefe, to divide the hold of a great fliip into a number of feparate chambers by partitions tight caulked, (of which you gave a model in your boat upon the Seine) fo that if a leak fliould fpring in one of them Q^q the 302 MARITIME OBSERVATIONS: the others are not affefted by it; and though that cham'-- ber fhould fill to a level with the fea, it would not be fuf- ficient to fink the veflc-l. We have not imitated this prac- tice. Some little difadvantage it might occaiion in the ftowage is perhaps one r^afon, though that I think might be more than compenfated by an abatement in the infu- rance that would be reafonable, and by a higher price taken of paffengers, who would rather prefer going in fuch a velTel. But our feafaring people are brave, defpife dan- ger, and rejed: fuch precautions of fafety, being cowards only in one fenfe, that oi fearing to be thought afraid. I promifed to finifh my letter with the laft obfervation, but the garrulity of the old man has got hold of me, and as I may never have another occafion of writing on this fubjedl, I think I may as well now, once for all, empty my nautical budget, and give you all the thoughts that have in my various long voyages occurred to me relating to navigation. I am fure that in you they will meet with a candid judge, who will excufe my miftakes on account of my good intention. There are fix accidents that may occafion the lofs of fhips at fea. We have confidered one of them, that of foundering by a leak. The other five are, i. Overfetting by fudden flaws of wind, or by carrying fail beyond the bearing. 2. Fire by accident or careleifnefs. 3. A heavy ftroke of lightning, making a breach in the Ihip, or firing the powder. 4. Meeting and ihocking with other fhips in the night. 5. Meeting in the night with iflands of ice. To that of overfetting, privateers- in their firft cruize have, as far as has fallen within my knowledge or infor- mation, been more fubjed than any other kind of vefl'els. The double defire of being able to overtake a weaker flying enemy, or toefcapewhenpurfued bya ftronger, has induced the owners to overmaft their cruizers, and to fpread too much canvas ; and the great number of men, many of them. MARITIME OBSERVATIONS. 303 'tliem not leamen, who being upon deck when a fliip heels fuddenly are huddled down to leeward, and increafe by their weight the cfFeitl of the wind. This therefore fliould be ■more attended to and guarded againft, efpecially as the advantage of lofty mails is problematical. For the upper fails have greater power to lay a veifel more on her fide, which is not the moft advantageous pofition for going ■fwiftly through the water. And hence it is that veflels which have loft their lofty marts, and been able to make little more lail afterwards than permitted the fliip to fail upon an even keel, have made fo much way, even under jury malls, as to lurprize the mariners themfclves. But there is befides, fomething in the modern form of our fliips that feems as if calculated exprefsly to allow their overfetting more eafily. The fides of a fliip inftead of fpreading out as they formerly did in the upper works, are of late years turned in, fo as to make the body nearly- round, and more refembling a cafk. I do not know what the advantages of this conltrudion are, except that fuch fhips are not fo eafily boarded. To me it feems a contri- vance to have lefs room in a fliip at nearly the fame ex- pence. For it is evident that the fame timber and plank confumed in railing the fides from a to b, and from d to c, would have raifed them from a to e, and from d to f, fig. n. In this form all the fpaces between e, a, b, and c, d, f, would have been gained, the deck would have been larger, the men would have had more room to a£t, and not have Ifood fo thick in the way of the enemy's fhot; and the velTel the more fhe was laid down on her fide, the more bearing flie would meet with, and more effedlual to fup- port her, as being farther from the center. Whereas in the prel'cnt form, her ballart makes the chief part of her bearing, without which Ihe would turn in the fea almofl as eafily as a barrel. More ballaft by this means becomes neceflary, and that finking a veffel deeper in the water occalioas more refiftance to her going through it. The Qjl 2 Bermudian 304 MARITIME OBSERVATIONS. Bermudlan floops ftill keep with advantage to the old' fpreading form. The iflanders in the great Pacific ocean, though they have no large fliips, are the moft expert boat- failors in the world, navigating that fea i'afely with their proas, which they prevent overfetting by various means. Their failing proas tor this purpofe have outrig2;ers gene- rally to windward, above the water, on which one or more men are placed to move occafionally further from or nearer to the veffel as the wind frefhens or flackens. But Tome have their outriggers to leeward, which refting on the water fupport the boat fo as to keep her upright when prelfed down by the wind. Their boats moved by oars or rather by paddles, are, for long voyages, fixed two together by crofs bars of wood that keep them at fome diftance from each other, and fo render their overfetting next to impoflible. How far this may be prafticable in larger veflels, we have not yet fufficient experience. I know of but one trial made in Europe, which was about one hundred years fince by, Sir William Petty. Rebuilt a double veffel, to ferve as a pacquet boat between England and Ireland. Her model ftill exifts in the mufeum of the Royal Society, where I have feen it. By the accounts we have of her, fhe anfwered well the purpofe of her con- flruftion, making feveral voyages; and though wrecked at laft by a ftorm, the misfortune did not appear owing to her particular conflrudion, fince many other veffels of the common form were wrecked at the fame time. The advantage of fuch a veffel is : That fhe needs no ballaff, therefore fwims either lighter or will carry more goods; and that paffengers are not fo much incommoded by her rolling: to which may be added, that if fhe is to defend herfelf by her cannon, they will probably have more ef- fect, being kept more generally in a horizontal pofition, than thofe in common veffels. I think however that it would be an improvement of that model, to make the fides which MARITIME OBSERVATIONS. 30-5 which are oppofed toeach other perfedly parallel, though the other Ikles are formed as in common thus, figure 10. The huilding of a double fhip would indeed be more expenfive in proportion to her burthen; and that perhaps is fufiicient to diicourage the method. The accident of fire is generally well guarded againft by the prudent captain's ftriti orders againft fmoking be- tween decks, or carrying a candle there out of a lanthorn. But there is one dangerous pracftice which frequent terrible accidents have not yet been fufficient to aboliili ; that of carrying ftore-fpirits to fea in cafks. Two large fhips, the Seraphis and the Duke of Athol, one an Eaft-Indiaman, the other a frigate, have been burnt within thefe two laft years, and many lives miferably deftroyed, by drawing fpirits out of a cafk near a candle. It is high time to make it a general rule, that all the fhip's ftore of fpirits fhould be carried in bottles. The misfortune by a ftroke of lightning I have in my former writings endeavoured to ihow a method of guard- ing againft, by a chain and pointed rod, extending, when run up, from above the top of the maft to the fea. Thefe inftruments are now made and fold at a reafonable prigs by Nairne and Co. in London, and there are feveral in- ftances of fuccefs attending the ufe of them. They are kept in a box, and may be run up and fixed in about five ininutes, on the apparent approach of a thunder guft. Of the meeting and fhocking with other fhips in the night, I have known two inftances in voyages between London and America. In one both fhips arrived though much damaged, each reporting their belief that the other muft have gone to the bottom. In the other, only one got to port ; the other was never afterwards heard of. Thefe inftances happened many years ago, when the com- merce between Europe and America was not a tenth part of what it is at prefent, fliips of courfe thinner fcattered, and the chance of meeting proportionably lefs. It has long been ^3o{S MARITIME OBSERVATIONS. been the practice to keep a look-out before in the channel, Init at fea it has been negledted. If it is not at prefent thought worth while to take that precaution, it will in time become of more confequence ; fince the number of fliips at fea is continually augmenting. A drum frequent- ly beat or a bell rung in a dark night, might help to pre- vent fuch accidents. Iflands of ice are frequently feen off the banks of New- foundland, by fliips going between North-America and Europe. In the day-time they are eafily avoided, unlefs in a very thick fog. I remember two inftances of fhips running againft them in the night. The firft loft her bowfprit, but received little other damage. The other ftruck where the warmth of the fea had wafted the ice next to it, and a part hung over above. This perhaps faved her, for flie was under great way ; but the upper part of the cliff taking her foretopmaft, broke the ftiock, though it carried away the maft. She difengaged herfelf with fome difficulty, and got fafe into port ; but the acci- dent fliows the polfibility of other fliips being wrecked and funk by ftriking thofe vaft maffes of ice, of which I have feen one that we judged to be feventy feet high above the water, confequently eight times as much under water; and it is another reafon for keeping a good look-out before, though far from any coaft that may threaten danger. It is remarkable that the people we confider as favages, have improved the art ot lailing- and rowing-boats in fe- veral points beyond what we can pretend to. We have no failing boats equal to the flying proas of the fouth feas, no rowing or paddling boat equal to that of the Green- landers for fwiftnefs and fafety. The birch canoes of the North-American Indians havealfo fome advantageous pro- perties. They are fo light that two men may carry one of them over land, which is capable of carrying a dozen upon the water ; and in heeling they are not fo fubjedl to take in water as our boats, the fides of which are. loweft MARITIME OBSERVATIONS. 307 Fowefl: in the middle where it is mofi: likely to enteiv this being highefl: in that part, as in figure i i. The Chinefe are an enlightened people, the moft anti- ently civilized of any exifting, and their arts are antient, a prefumption in their favour: their method of rowing their boats differs from ours, the oars being worked either f two a-ftern as we fcull, or on the fides with the fame kind of motion, being hung parallel to the keel on a rail and always ading in the water, not perpendicular to the fide as ours are, nor lifted out at every itroke, which is a lofs of time, and the boat in the interval lofes motion. They {cc our manner, and we theirs, but neither are difpofed to learn of or copy the other. To the feveral means of moving boats mentioned above, may be added the fingular one lately exhibited at Javelle, on the Seine below Paris, where a clumfy boat was mov- ed acrols that river in three minutes by rowing, not in the water, but in the air, that is, by whirling round a fet of windmill vanes fixed to a horizontal axis, parallel to the keel, and placed at the head of the boat. The axis was bent into an elbow at the end, by the help of which it was turned by one man at a time. I faw the operation at a diftance. The four vanes appeared to be about five feet long, and perhaps two and a half wide. The weather •was calm. The labour appeared to be great for one man, as the two feveral times relieved each other. But the ac- tion upon the air by the oblique furfaces of the vanes mull have been conlidcrable, as the motion of the boat aiipear- ed tolerably quick going and returning ; and fhe returned to the fame place from whence fhe firft fet out, notwith- ftanding the current. This machine is fince applied to the moving of air balloons : An inftrument fimilar may be contrived to move a boat by turning under water. Several mechanical projedors have at different times propofed to give motion to boats, and even to fliips, by means of circular rowing, or paddles placed on the circum- ference. 3o8 MARITIME OBSERVATIONS. ferencc of wheels to be turned conftantly on each fide of the veffel ; but this method, though frequently tried, has never been found fo effeftual as to encourage a continuance of the pradice. I do not know that the reafon has hither- to been given. Perhaps it may be this, that great part of the force employed contributes little to the motion. For inftance, (fig. 12.) of the four paddles a, b, c, d, all under water, and turning to move a boat from X to Y, c has the moft power, b nearly though not quite as much, their motion being nearly horizontal ; but the force employed in moving a, is confumed in prefTmg almoft downright upon the vv'ater till it comes to the place of b ; and the force employed in moving d is confumed in lifting the water till d arrives at the furface ; by which means much of the labour is loft. It is true, that by placing the wheels higher out of the water, this wafte labour will be diminiih- ed in a calm, but where a fea runs, the wheels muft un- avoidably be often dipt deep in the waves, and the turn- ing of them thereby rendered very laborious to little purpofe. Among the various means of giving motion to a boat, that of M. Bernoulli appears one of the moft fingular, which was to have fixed in the boat a tube in the form of an L, the upright part to have a funnel-kind of opening at top, convenient for filling the tube with water; which defcending and paffing through the lower horizontal part, and iffuing in the middle of the ftern, but under the fur- face of the river, fhould pufti the boat forward. There is no doubt that the force of the defcending water would have a confiderable effe£l, greater in proportion to the height from which it defcended ; but then it is to be confi- dered, that every bucket-full pumped or dipped up into the boat, from its fide or through its bottom, muft have its I'is inertice overcome fo as to receive the motion of the boat, before it can come to give motion by its defcent; and that will be a dedudlion from the moving power. To MARITIME OBSERVATIONS. 309 To remedy this, I would propofe the addition of another fuch L pipe, and that they fliould ftand back to back in the boat thus, figure 13. the forward one being worked as a pump, and lucking in the water at the head of the boat, would draw it forward while pufhed in the fame di- rection by the force at the ftern. And after all it fhould be calculated whether the labour of pumping would be lefs than that of rowing. A fire-engine might poflibly in fome cafes be applied in this operation with advantage. Perhaps this labour of raifing water might be fpared, and the whole force of a man applied to the moving of a boat by the ufe of air inftead of water ; fuppofe the boat conftrufted in this form, figure 14. A, a tube round or fquare of two feet diameter, in which a pifton may move tip and down. The pifton to have valves in it, opening inwards to admit air when the pifton rifes; and ftiutting, ■when it is forced down by means of the lever B turning on the center C. The tube to have a valve D, to open ■when the pifton is forced down, and let the air pafs out at E, which ftriking forcibly againft the water abaft muft pulh the boat forward. If there is added an air-veflel F properly valved and placed, the force would continue to aft while a frefli ftroke is taken with the lever. The boat- man might ftand with his back to the ftern, and putting his hands behind him, work the motion by taking hold of the crofs bar at B, while another ftiould fteer ; or if he had two fuch pumps, one on each fide of the ftern, with a lever for •each hand, he might fteer himfelf by working occafionally more or harder with either hand, as watermen now do with a pair of fculls. There is no pofition in which the body of a man can exert more ftrength than in pulling right upwards. To obtain more fwiftnefs, greafing the bottom ot a vef- fel is fometimes ufed, and with good efFeft. I do not know that any writer has hitherto attempted to explain this. At firft fight one would imagine, that though the fri<3;ion of a hard body Hiding on another hard body, and R r the 3I.O MARITIME OBSERVATIONS.. the refiftance occafioned by that fridlion, might be dlmi-- niflicd by piUthig greafe between them, yet that a body Aiding on a fluid, I'uch as water, Ihould have no need of nor receive any advantage from fuch greafing. But the fa£t is not difputed. And the reafon perhaps may be this. The particles of water have a mutual attraction, called the attraction of adhefion. Water alio adheres to wood, and to many other fubftances, but not to greafe: On the contrary they have a mutual repulfion, fo that it is a queftion v/hether when oil is poured on water, they ever actually touch each other ; for a drop of oil upon water, inftcad of flicking to the fpot where it falls, as it would if it fell on a looking-glafs, fpreads inftantly to an immenfe diftance in a film extremely thin, which it could not eafily do if it touched and rubbed or adhered even in a fmall de- gree to the furface of the water. Now the adhefive force of. water to itfelf, and to other fubftances, may be eftimated. from the weight of it neceffary to feparate a drop, which adheres, while growing, till it has weight enough to force the feparation and break the drop off. Let us fuppofe the drop to be the fize of a pea, then there will be as many of thefe adhefions as there are drops of that fize touching the bottom of a vefTel, and thefe muft be broken by the moving power, every ftep of her motion that amounts to a drop's breadth : And there being no fuch adhefions to break between the water and a greafed bottom, may oc^ cafion the difference. So much refpeCting the motion of veflels. But we have fometimes occafion to flop their motion ; and if a bottom is near enough we can caft anchor : Where there are no foundings, we have as yet no means to prevent driving in a ftorm, but by lying-to, which ftill permits driving at the rate of about two miles an hour; fo that in a ftorm continuing fifty hours, which is not an uncornmon cafe, the ftiip may drive one hundred miles out of her courfe ; and fliould Ihe in that diftance meet with a lee fliore, fhe may be loft. To MARITIME OBSERVATIONS. 311 To prevent this driving to leeward in deep water, a fwimming anchor is wanting, which ought to have thefe properties. 1. It fhould have a furface fo large as being at the end of a haufer in the water, and placed perpendicularly, fhould hold fo much of it, as to bring the Ihip's head to the wind, in which fituation the wind has leait power to drive her. 2. It fhould be able by its refiftance to prevent the fliip's receiving way. 3. It fhould be capable of being fituated below the heave of the fea, but not below the undertow. 4. It fhould not take up much room in the fliip. 5. It Ihould be eafily thrown out, and put into its pro- per fituation. 6. It fhould be eafy to take in again, and flow away. An ingenious old mariner whom I formerly knew, pro- pofed as a fwimming anchor for a large fliip to have a item of wood twenty-five feet long and four inches fquare, with four boards of 18, 16, 14, and 12, feet long, and one foot wide, the boards to have their fubftance thickened feveral inches in the middle by additional wood, and to have each s. four inch fquare hole through its middle, to permit its being flipt on occafionally upon the ftem, and at right angles with it ; where all being placed and fixed at four feet diflance from each other, it would have the appear- ance of the old mathematical inftrument called a foreftafF. This thrown into the fea, and held by a haufer veered out to fome length, he conceived would bring a veflel up, and prevent her driving, and when taken in might be Itowed away by feparating the boards from the ftem. Figure ic. Probably fuch a fwimming anchor would have fome good efFe£t, but it is fubjedt to this ohjedion, that lying on the furface of the fea, it is liable to be hove forward by every wave, and thereby give fo much leave for the fliip to drive. R r 2 Two 312 MARITIME OBSERVATIONS.. Two machines for this purpofe have occurred to mci •which though not fo fimple as the above, I imagine would be more efFectual, and more eafily manageable. I will endeavour to defcribe them, that they may be fubmitted to your judgment, whether either would be ferviceable; and if they would, to which we Ihould give the prefer- ence. The firft is to be formed, and to be ufed in the water on almofi: the fame principles with thofe of a paper kite ufed in the air. Only as the paper kite rifes in the air, this is to delcend in the water, its dimenfions will be different for Ihips of different fize. To make one of fuppofe fifteen feet high ; take a fmall fpar of that length for the back-bone, AB, figure i6, a fmaller of half that length C D, for the crofs piece. Let thefe be united by a bolt at E, yet fo as that by turning on the bolt they may be laid parallel to each other. Then make a fail of ftrong canvas, in the fhape of figure 17. To form this, without wafte of fail-cloth, few together pieces of the proper length, and for half the breadth, as in figure 18, then cut the whole in the diagonal lines a, b, c, and turn the piece F fo as to place its broad part op- pofite to that of the piece G, and the piece H in like man- ner oppofite to I, which when all fewed together will ap- pear as in figure 17. This fail is to be extended on the crofs of figure 16, the top and bottom points well fecured to the ends of the long fpar ; the two fide points d, e» faftened to the ends of two cords, which coming from the angle of the loop (which mufl be fimilar to the loop of a kite) pafs through two rings at the ends of the fhort fpar, fo as that on pulling upon the loop the fail will be drawn to its extent. The whole may, when aboard, be furled up, as in figure 19, having a rope from its broad end, to which is tied a bag of ballaft for keeping that end down- wards when in the water, and at the other end another rope with an empty keg at its end to float on the furface ; this MARITIME OBSEPvVATIONS* 31- this rope long enough to permit the kite's defcending into the undertow, or if you pleale lower into ftill water. It fl^ould be held by a haufer. To get it home eafily, a fmall loofe rope may be veered out with it, hxed to the keg.- Hauling on that rope will bring the kite home with fmall force, the refiftance being fmall as it will then come endways. It feems probable that fuch a kite at the end of a long hauler would keep a fliip with her head to the wind, and refilling every tug, would prevent her driving fo faft as •when her iide is expofed to it, and nothing to hold her back. If only half the driving is prevenied, fo as that fhe moves but fifty miles inftead of the hundred during a ftorm, it may be fome advantage, both in holding fo much diftance as is faved, and in keeping from a lee Ihore. If fingle canvas fliould not be found ftrong enough to bear the tug without fplitting, it may be doubled, or ilrength- cned by a netting behind it, reprefented by figure 20. The other machine for the fame purpofe, is to be made more in the form of an umbrella, as reprefented, figure 21* The ftem of the umbrella a fquare fpar of proper length, •with four moveable arms, of which two are reprefented C, C, figure 22. Thefe arms to be fixed in four joint cleats, as D, D, &c. one on each fide of the fpar, but fo as that the four arms may open by turning on a pin in the joint. When open they form a crofs, on which a four fquare canvas fail is to be extended, its corners faft- ened to the ends of the four arms. Thofe ends are alfo to be ftayed by ropes faflened to the ftem or fpar, fo as to keep them ftiort of being at right angles with it: And to the end of one of the arms ftiould be hung the fmall bag of ballaft, and to the end of the oppofite arm the empty keg. This on being thrown into the fea, would immedi- ately open; and when it had performed its function, and the ftorm over, a fmall rope from its other end being pulled on, would turn it, clofe it, and draw it eafily home to the fhip. This machine feems more fimple in its ope-- ration, 314 MARITIME OBSERVATIONS. ration, and more eafily manageable than the firft, and perhaps may be as efFedlual.* Veflels are fometimes retarded, and fometimes forward- ed in their voyages, by currents at fea, which are often not perceived. About the year 1 769 or 70, there was an application made by the board of cuftoms at Bofton, to the lords of the treafury in London, complaining that the packets between Falmouth and New- York, were general- ly a fortnight longer in their paflages, than merchant fhips from London to Rhode-lfland, and propofmg that for the future they iTiould be ordered to Rhode-lfland inftead of New-York. Being then concerned in the manage- ment of the American poft-office, I happened to be con- fulted on the occafion; and it appearing ftrange to me that there Ihould be fuch a difference between two places, fcarce a day's run afunder, efpecially when the merchant fhips are generally deeper laden, and more weakly man- ned than the packets, and had from London the whole length of the river and channel to run before they left the land of England, while the packets had only to go from Falmouth, I could not but think the fa£t mifunder- ftood or mifreprefented. There happened then to be in London, a Nantucket fea-captain of my acquaintance, to •whom I communicated the affair. He told me he believ- ed the fa(3; might be true ; but the difference was owing to this, that the Rhode-lfland captains were acquaint- ed with the gulf ftream, which thofe of the Englifh packets were not. We are well acquainted with that flream, fays he, becaufe in our purfuit of whales, which keep near the fides of it, but are not to be met with in it, we run down along the fides, and frequently crofs it to change our fide: and in croffing it have fometimes met and fpoke with thofe packets, who were in the middle of it, and fl:emming it. We have informed them that they were * Cnptain Tnixton, on board -wliofe Clip this was written, has executed this propofcd machine; he has given fix arms to the umbrella, they are jcined to the fieri by iron hijiges, ajid the canvas is double. He has taken it witJi him to China. February 1786. MARITIME OBSERVATIONS. 315 •were ftemming a current, that was againft them to the vahie of three miles an hour; and adviied them to crofs it and get out of it; but they were too wife to be coun- felled by fimple American fifhermen. When the winds are but light, he added, they are carried back by the current more than they are forwarded by the wind: and if the wind be good, the fubtraftion of 70 miles a day from their courfe is of fome importance. I then obferved that it was a pity no notice was taken of this current up- on the charts, and requefted him to mark it out tor me, ■which he readily complied with, adding directions for a- voiding it in failing from Europe to North-America. I procured it to be engraved by order from the general poft- office, on the old chart of the Atlantic, at Mount and Page's, Tower-hill ; and copies were fent down to Falmouth for the captains of the packets, who flighted it however ; but it is fmce printed in France, of which edition I hereto an- nex a copy. This ftream is probably generated by the great accu- mulation of water on the eailern coaft of America between the tropics, by the trade winds which conftantly blow there. It is known that a large piece of water ten miles broad and generally only three feet deep, has by a ftrong wind had its waters driven to one fide and fuftained fo as to become fix feet deep, while the windward lide was laid dry. This may give fome idea of the quantity heaped up on the American coaft, and the reafon of its running down in a ftrong current through the iflands into the bay of Mexico, and from thence ifluing through the gulph of Florida, and proceeding along the coaft to the banks of Newfoundland, where it turns off towards and runs down through the Weftern iflands. Having fince crofled this ftream feveral times in pafling between America and Eu- rope, I have been attentive to fundry circumftances relat- ing to it, by which to know when one is in it; and be- fides the gulph weed with which it is interfperfed, I find that 3i6 MARITIME OBSERVATIONS. that it is always warmer than the fea on each fide of it, and that it does not fparkle in the night : I annex hereto the obfervations made with the thermometer in two voy- ages, and poffibly may add a third. It will appear from them, that the thermometer may be an ufeful inftrument to a navigator, fince curreiits coming from the northward into fouthern feas, will probably be found colder than the ■water of thofe feas, as the currents from fouthern feas into northern are found warmer. And it is not to be wonder- ed that fo vaft a body of deep warm water, feveral leagues wide, coming from between the tropics and iffuing out of the gulph into the northern feas, fhould retain its warmth longer than the twenty or thirty days required to its paf- fmg the banks of Newfoundland. The quantity is too great, and it is too deep to be fuddenly cooled by paffing under a cooler air. The air immediately over it, how- ever, may receive fo much warmth from it as to be rari- fied and rife, being rendered lighter than the air on each fide of the ftream; hence thofe airs muft flow in to fup- ply the place of the rifing warm air, and meeting with each other, form thofe tornados and water-fpouts fre- quently met with, and feen near and over the ftream; and as the vapour from a cup of tea in a warm room, and the breath of an animal in the fame room, are hardly vifi- ble, but become fenfible immediately when out in the cold air, fo the vapour from the gulph ftream, in warm lati- tudes is fcarcely vifible, but when it comes into the cool air from Newfoundland, it is condenfed into the fogs, for ■which thofe parts are fo remarkable. The power of wind to raife water above its common level in the fea, is known to us in America, by the high tides occafioned in all our fea-ports when a ftrong north- eafter blows againft the gulph ftream. The conclufion from thele remarks is, that a vefiel from Europe to North-America may fliorten her paffage by a- voiding to ftem the ftream, in which the thermometer will be MARITIME OBSERVATIONS. 317 be very ufeful ; and a veflel from America to Europe may do the fame by the fame means of keeping in it. It may have often happened accidentally, that voyages have been fhortened by thefe circumftances. It is well to have the command of them. But may there not be another caufe, independent of winds and currents, why palTages are generally fhorter from America to Europe than from Europe to America ? This queftion I formerly confidered in the following fhort paper. On board the Pennfylvania Packet, Capt. Ofborne, At fea, April 5, 1775. " Suppofe a fhip to make a voyage eallward from a place in lat. 40° north, to a place in Lit. 50° north, diftance in longitude 75 degrees. " In failing from 40 to 50, fhe goes from a place where a degree of longitude is about eight miles greater than in the place fhe is going to. A degree is equal to four mi- nutes of time ; confequently the Ihip in the harbour fhe leaves, partaking of the diurnal motion of the earth, moves two miles in a minute fafler, than when in the port fhe is going to ; which is 120 miles in an hour. " This motion in a fhip and cargo is of great force; and if flie could be lifted up fuddenly from the harbour ia which fhe lay quiet, and fet down inflantly in the latitude of the port fhe was bound to, though in a calm, that force contained in her would make her run a great way at a prodigious rate. This force mufi: be loft gradually in her A'oyage, by gradual impulfe againft the water, and proba- bly thence fhorten the voyage. Query, In returning does the contrary happen, and is her voyage thereby retarded and lengthened ?" * Would it not be a more fecure method of planking fhips, if iurtead of thick fingle planks laid horizontally, we were S s to " SInif thi* paper was read at the Soc:ety, an ingenious memlicr, Mr. Pattcrfon, lias con- vinced tilt writer that the returning voyage would not, trom this caufe, be retarded. 3i8 MARITIME OBSERVATIONS. to life planks of half the thicknefs, and lay them double- and acrofs each other as in figure 23 ? To me it feems thac the difference of expence would not be confiderable, and that the fhip would be both tighter and ftronger. The fecuring of the ihip is not the only neceifary thing;: fecuring the health of the failors, a brave and valuable or-- der of men, is likewife of great importance. With this view the methods fo fuccefsfully pradlifed by Captain Cook in his long voyages, cannot be too clofely lUidied or care- fully imitated. A full account of thofe methods is found in Sir John Pringle's fpeech, when the medal of the Royal Society was given to that illuftrious navigator. T am glad to fee in his laft voyage that he found the means efFeftual ■which I had propofed tor preferving flour, bread, &c. from moifture and damage. They were found dry and good after being at fea four years. The method is defcribed in my printed works, page 452, fifth edition. In the fame," page 469, 470, is propofed a means of allaying thirff in cafe of want of frefh water. This has fmce been pradlifed in two inftances with fuccefs. Happy if their hunger,, when the other provifions are confumed, could be relieved as commodioufly ; and perhaps in time this may be found not impoffible. An addition might be made to their pre- fent vegetable provifion, by drying various roots in flices- by the means of an oven. The fweet potatoe of Ameri-- ca and Spain, is excellent for this purpofe. Other po- tatoes, with carrots, parfnips and turnips, might be pre- pared and preferved in the fame manner. With regard to make-ihifts in cafes of neceffity, feamen^ are generally very ingenious themfelves. They will ex- cufe however the mention of two or three. If they hap- pen in any circumftance, fuch as after fhipwreck, taking to their boat, or the like, to want a compafs, a fine few- ing-needle laid on clear water in a cup will generally point to the north, moft of them being a little magnetical, or may be made fo by being flrongly rubbed or hammer- ed. MARITIME OBSERVATIONS. 319 ted, lying in a north and fouth dIre£lion. If their needle is too heavy to float by itfelf, it may be fupported by little pieces of cork or wood. A man who can fwim, may be aided in a long traverfe by his handkerchief formed into a kite, by two crofs fl:icks extending to the four corners;, which being raifed in the air, when the wind is fair and frefli, will tow him along while lying on his back. Where force is wanted to move a heavy body, and there are but few hands and no machines, a long and ftrong rope may make a powerful inftrument. Suppofe a boat is to be drawn up on a beach, that flie may be out of the furf, a flake drove into the beach where you would have the boat drawn ; and another to faften the end of the rope to, which comes from the boat, and then applying what force you have to pull upon the middle of the rope at right angles with It, the power will be augmented in proporti- on to the length of rope between the ports. The rope being faftened to the flake A, and drawn upon in the di- redion C D, will Aide over the flake B; and when the rope is bent to the angle A D B, reprefented by the prick- ed line in figure 24, the boat will be at B. Some failors may think the writer has given himfelf un- neceflTary trouble in pretending to advife them ; for they have a little repugnance to the advice of landmen, whom they efteem ignorant and incapable of giving any worth notice; though it is certain that moft of their inftruments were the invention of landmen. At leaft the firft veflel ever made to go on the water was certainly fuch. I will therefore add only a few words more, and they fliall be addreflTed 'to paflengers. When you intend a long voyage, you may do well to keep your intention as much as poflible a fecret, or at leall the time of your departure ; otherwife you will he conti- nually interrupted in your preparations by the vifits of friends and acquaintance, who will not only rob you of the time you want, but put things out of your mind, fo S s 2 that 320 MARITIME OBSERVATIONS. that when you come to fea, you have the mortification to recollect points of bufinefs that ought to have been done, accounts you had intended to fettle, and conveniencies you had pr.opofed to bring with you, &c. &c. all which have been omitted through the effed of thefe officious friendly vifits. Would it not be well if this cuftom could be chang- ed ; if the voyager after having, without interruption, made all his preparations, fhould ufe fome of the time he has left, in going himfelf to take leave of his friends at their own houfes, and let them come to congratulate him on his happy return. It is not ahvays in your power to make a choice in your captain, though much of your comfort in the palTage may depend on his perfonal charadler, as you muft for fo long a time be confined to his company, and under his direc- tion ; if he be a fenfible, fociable, good natured, obliging man, you will be fo much the happier. Such there are ; but if he happens to be otherwife, and is only fkilful, careful, watchful and aftive in the condud of his fhip, excufe the reft, for thefe are the eflentials. Whatever right you may have by agreement in the mafs of ftores laid in by him for the paflengers, it is good to have fome particular things in your own pofTeffion, fo as to be always at your own command. I. Good water, that of the fiiip being often bad. You can be fure of having it good only by bottling it from a clear fpring or well and in clean bottles. 2. Good tea. 3. Coffee ground. 4. Chocolate. 5. Wine of the fort you particularly like, and cyder. 6. Raifins. 7.. Almonds 8. Sugar. 9. Capillaire. 10. Lemons. 1 1. Jamaica fpirits. 12. Eggs greas'd. 13. Diet bread. 14. Portable foup. 15. Rufks. As to fowls, it is not worth while to have any called yours, unlefs you could have the feeding and managing of them according to your own judgment under your own eye. As they are generally treated at prefent in fhips, they are for the moft part fick, and their flefh tough MARITIME OBSERVATIONS. 321 tough and hard as whitleather. All feamen have an opi- nion, broached I fuppoled at firft prudently, for faving of water when Ihort, that fowls do not know when they have drank enough, and will kill themfelves if you give them too much, fo they are ferved with a little only once in two days. This is poured into troughs that lie llope- ing, and therefore immediately runs down to the lower end. There the fowls ride upon one another's backs to get at it, and fome are not happy enough to reach and once dip their bills in it. Thus tantalized, and torment- ed with thirft, they cannot digefl: their dry food, they fret, pine, ficken and die. Some are found dead, and thrown overboard every morning, and thofe killed for the table are not eatable. Their troughs fhould be in little divill- ons like cups to hold the water feparately, figure 25. But this is never done. The flieep and hogs are therefore your befl: dependance for frelh meat at fea, the mutton being generally tolerable and the pork excellent. It is polTible your captain may have provided fo well in the general ftores, as to render fome of the particulars above recommended of little or no ufe to you. But there are frequently in the fhip poorer paifengers, who are taken at a lower price, lodge in the fteerage, and have no claim to any of the cabbin provifions, or to any but thofe kinds that are allowed the failors. Thefe people are fometimes dejected, fometimes fick, there may be women and children among them. In a fituation where there is no going to market, to purchafe fuch neceiTaries, a few of thele your iupertiuities diftributed occafionally may be of great lervice, reftore health, fave lite, make the mi- ferable happy, and thereby afford you infinite pleafiire. The worll thing in ordinary merchant Ihips is the cookery. They have no profeifed cook, and the worft hand as a feamanjis appointed to that office, in which he is not only very ignorant but very dirty. The failors have 322 MARITIME OBSERVATIONS. ■have therefore a faying, that God fends meat and the devil cooks. Paffengers more pioufly difpofed, and willing to believe heaven orders all things for the beft, may fuppofe that knowing the fea-air and conftant exercife by the mo- tion of the veflel would give us extraordinary appetites, bad cooks were kindly fent to prevent our eating too much ; or, that forefeeing we fhould have bad cooks, good appetites were furniflied to prevent our ftarving. If you cannot truft to thefe circumllances, a fpirit-lamp, with a blaze-pan, may enable you to cook fome little things for yourfelf ; fuch as a halh, a foup, &c. And it might be well alfo to have among your ftores fome potted meats, which if well put up will keep long good. A fmall tin- oven to place with the open fide before the fire, may be another good utenfil, in which your own fervant may roaft for you a bit of pork or mutton. You will fometimes be induced to eat of the Ihip's fait beef, as it is often good. You will find cyder the beft quencher of that thirft which fait meat or fifh occafions. The ihip bifcuit is too hard for fome fets of teeth. It may be foft- ened by toafting. But rufk is better; for being made of good fermented bread, fliced and baked a fecond time, the pieces imbibe the water eafily, foften immediately, digeft more kindly and are therefore more wholfome than the unfermented bifcuit. By the way, rufk is the true ori- ginal bifcuit, fo prepared to keep for fea, bifcuit in French fignifying twice baked. If your dry peas boil hard, a two-pound iron fhot put with them into the pot, will by the motion of the fhip grind them as fine as muftard. The accidents I have feen at fea with large diflies of foup upon a table, from the motion of the fhip, have made me wiih that our potters or pewterers would make foup- difhes in divifions, like a fet of fmall bowls united toge- gether, each containing about fufficient for one perfon, in fome fuch form as fig. 26 ; for then when the fhip fhould .make a hidden heel, the foup would not in a body flow over MARITIME OBSERVATIONS. ^^^ J over one fide, and fall into people's laps and fcald them,, as is fometimes the cafe, hut would be retained in the fe- parate diviiions, as in figure 27. After thefe trifles, permit the addition of a few general reflexions. Navigation when employed in fupplying ne- celfary provific^ns to a country in want, and thereby pre- venting famines, which were more frequent and deftruc- tive before the invention of that art, is undoubtedly a bleffing to mankind. When employed merely in tranf- porting fuperfluities, it is a queftion whether the advan- tage of the employment it affords is equal to the mil- chief of hazarding ib many lives on the ocean. But when employed in pillaging merchants and tranfporting flaves, it is clearly the means of augmenting the mafs of human milery. It is amazing to think of the fhips and lives rifqued in fetching tea from China, coffee from Arabia, fugar and tobacco from America, all which our anceftors did well without. Sugar employs near one thoufand fhips, tobacco almofl as many. For the utility of tobacco there is little to be faid ; and for that of fugar, how much more commendable would it be if v/e could give up the few mi- nutes gratification afforded once or twice a day by the tafte of fugar in our tea, rather than encourage the cruelties exercifed in producing it. An eminent French moralift fays, that when he confiders the wars we excite in Africa to obtain flaves, the numbers necefl'arily flain in thofc wars, the many prifoners who perifh at fea by ficknefs, bad pro- vifions, foul air, &c. &c. in the tranfportation, and how many afterwards die from the hardfhips of flavery, he can-- not look on a piece of fugar without conceiving it ftained with fpots of human blood ! Had he added the confidera- tion of the wars we make to take and retake the fugar iflands from one another, and the fleets and armies that perifh in thole expeditions, he might have feen his fugar not merely fpotted, but thoroughly dyed fcarlet in grain. It is thefe wars that make the maritime powers of Europe, the 324 MARITIME OBSERVATIONS. the inhabitants of London and Paris, pay dearer for fugar than thoi'e of Vienna, a thoufand miles from the fea ; be- caufe their fugar cofts not only the price they pay for it by the pound, but all they pay in taxes to maintain the fleets and armies that fight for it. With great efteem, I am, Sir, Your moft obedient humble fervant, B. FRANKLIN. Obfervatlons MAUTTIME OBSERVATIONS. 32J 'be i^ '*—' a. o >-i u 4-4 .s (J i-l al OJ Oi 4-1 u oJ e C lO o a 1^ S > t^ b .>^ (1) CT ^ G ^ 4-> (-; cS U3 4-1 S (U I) -a ^ -rt a C *-> CJ ?^ -3 r3 ^ n a. '^ IS on "^ 0 oo r* *t »>-, •(^ apniuET O f^OO vO o *o fO o o »^ r^ f^ f^ 1^ oo oo oo •53UE^J!a 'I'M' *^ ^^*^>^'0«J'MWOOOO»oOO •sjano3 ' •P"!AV «^ 1 w & ^^^ ■iE,wjo-diu3x rtMTi-i^»^00 -l-0<-.rtvOOOr<OI-.00 wo M r^M TJ-1.^00 WVO M (v. Date. 2S2:r-^>gjr^ 1 s^l 1 ?,l 1 1 " 1 1 1 « 1 1 1 " t s Tt Obfervations 326 MARITIME OBSERVATIONS. o C 4J a O -a C! o > r3 ^-' !> V- r>. « flj ^^ "^ I-. ^ rt O ■S -Q ■^ cS O C ^ « '^^ o C ^ „ ^ Jc OJ bO •£ "'H i-> S-. *J rt 3 s^ o? ■s rS S •i C ii So o iiO eg O^- Q O f< r', f-. oo t^ C» SO M Lr- r<-i tH fS *o 't ^. ■A\ -SuoT O oo X-, c* OO *^ «^ (1 o ?^ SO SO >0 »ri ^ to »o lo T <* -: O VD ^ f^ NO c< OS c< C< c^ M -JilET O .■ti t^ o »^ »0 so oo CS -O <^ f^ *^ C^ (O to i^ C\ w o -^ c^ ^ oo >^ ^ fj o •r so cs so r^ O r^ r-. ■.-lOUB^JlQ l-l M 11 I-* w M •3;jno3 [£j W ^ CS K t--] w w WW Z ^ « z 21 z ^ ^ s -o w T"!.V\ w „ '-/: ?: ^ y: ?* z z W CO c/: w •jajE.W O *H oo M ir,00 ■OsC>CsOs3>£sOOOnO »^. ^ i^sO t^OO r-. t-. r^ r^ J-^ t^ D p -diuax r— c-^ r-oo t-^t-^f>.r^r»r-*t-^t^r^ r^r^r. r- r^ f-^ r^ t^ r^ t-* c^ r^ t^ r- ti ■JIV so MM r^ O oo oo oo o •^ ^ ^ JO -diuox t^ <^ i-^ so r-.>0 so NO r-. i^ (-- ■IV d n- ^ ^ t M ^CC ^00 ■ 00 rl oo rt oo c* CS c5 Cs r> jnoH M M M h- I M 1 CI 1 1 <-; 1 1^1 1 1 "^ 1 1 1 "^ 1 ^ 1 1 ^ 1 1 ^ 1 '^- 1 1 11 11 II 1 1 It 1 1 1 1 1 1 J 1 g o -^ Obfervations TVTARITIME OBSERVATIONS. 327 "T3 .s .4-1 o -T3 CS O c o -a to G .2 > o (-3 •* j3 (^ g. i CO 1 -3 c 3 CO r^ CS r» t^ »o *^ t* r^ o*. i-i ^00 »0 »o c< ^ T t ^ rl- ■<:1- -<*- '<■ -* M M ^ 00 vO 00 >o ■33UE1]I(J HI IH M <*• '^as':? 0\ "^ Os CN Cl CO M M M M •J3fn03 w w W tq W H ^ w 1^ www ov-o „ 00 -so 00 _ CO 00 00 00 t-^ <-^ so » r.oo ^ ^^ ---^ ^ z 2; ZmZ z 2; ZZZvj "^ -J2 -j:) 2 CO 15 •P"!AV w CO ^ w^ .^w y5 u: ;>;2i;zi w W CO Z W W C/D W c/: en 2 •J-'l^AV M CO ■^ <-o M 0*00 rt Ht O\«0 pN. r^ c^ c^ *«■»*- rt JO -diusj^ C>.»0 ^0 >0 ^ ^ NO »0 >0 ^ 'O >0 *0 "O >0 ^ >0 trj t/-ll •jrv •0 HI JO -diuax »^ >o ^o >0 10 lo •IM d "T c ^ 1 ^ * Of ^ . . . . jnoH •5 ^ z ^z o-o-c-rr T3-^ ^ — •JAI-V 00 r^OO C^OO "00 00 00 ^ 00 jnoH ^ "^ CNO 1 H 1 ^ 1 -^ -t 1 1 "^ 1 vO r-CO On 1 w r» "^ %■ ^o^o r^OO ^ W 1 M 1 M 1 HI M 1 1 H. 1 « , W M M rt 1 Tt 2 328 MARITIME OBSERVATIONS. (J -> O > O C O CO N. B. Longitude is reckoned from London, and the Thermometer is according to Fahrenheit. 1 4J ;> r^ r^ r^oo r^ r^ r-- r^ r- t^-c t^ r^ t^ r^ r-» r^ r>-oo 00 00 00 00 00 00 00 t-^00 t>. rr^M csi-i ost-^r-^O E »^0 O'-'OO c^oa '-^"^'^-'^c^oooc "^,00 00 ■< r-00 r--oo 0000 r^ r^ r^oo r^oo 00 oc r^ t^ r^oo oooooooooo i^i^r-.r-.n,. r: ^ c y . o o o o >-» o o (^ f^ t^ M jj c rt C -O ?^-0 C^ ">S NO ? "5 ii M 't O <^ ?:^. t^>0 t-O 00 f. O -a-O M t--->0 C\ --3 M OO « «. CO on I--00 <^ o " 3 O 2'3 ^ ^^«^««„««^||..«Z^.^.^Zx.Zx^|Z«^c.^^^^^^y«2 2 i < <^ cfl t E d "^ w 00 <-! «^. t-.so sooow CKM coo £0000010 00 w 00 00 00 w £ TT-jr^j;? J? ^-^ ^ '^ :^ r--00 00 »S -tj- r-.so >^0O •- f^ -^ "i- '^vS 'O OOO O^oo r-^-O tJ-sO t^ c^'O ^O *^nO 00 00 0*CO O O OOw O OvCs*^. *^. '^. »o^w ■^nO'O'C^o i^r^r^t->.r--r--.t--t^t-~r^t^r->.r-r-»t^r^f^t~^t~*»^'^'^<~^t^f^ r^oo oooooooooo i^r^r^ 1^ < "^ 'O >Q ^ ^ ^ >C ^0 r-t^t^t^r^r^t^r^r-^r^ r^oo 00 r^r-%r-t^r^t^r^t^t^t^t^ r^oo oooooooeoooooo r-^f-^t>^ S o xoOC •^". <^, ^^'^■^OOOr»OP''-<-,oo 00 *o«^'^f<0 OH' >^r< •n** r^ r-.oo 00 >n O «nr»C O ^f'-, r»»nO 0*nOO ^O 0'n<^C C\50 r- «n "^ »-* 00 'O »n 'o "^ *^ ^' "^ *^- ^ >nvO r^O >n "n ^n ^ "n *^ ^ ^ >f ^ "^ •+ »n *n ^n^O ^ "i*- lo r-^ ^. ■-« M ci d It *^jso t^oo c '-' r* •—. -^ i^.sO r-oo CN '-' c* "-o ■^ i^.^O r--00 Cn O m m- rt e*^ — H E M A k K NZWrOUNUI. ANU Tb N Z W- Y oa1(f|^^ Jm t^Mr h a%tiJ lit O II L 1' il Jl 7 K. £ A M ' • AfTI^R >'>„l.uvr f^rrr.t ihc Iluilu of NtwroundUnd !n a£oi« >'" I i ' ' . yuu wiU meet Mfith autliiiiK, till J"" ■'' ' ■■ whuh wc commonly pait in U- ■ "u- fH'l il" 1(1' nf Sibln, (hanc youf couric for (h* St. f ' * ' I'lf* lliriii in Aliriut Utiludc 40'^, bcoulc '' til. ill b-fik» lc«.ljt- *, 1*1 Nunii A* Jy . • ' ■ li' 111 41' Ji'- Allsr haviBK piiEcJ Si, Ucotkc '■ Ibuk*. ]tiui nuiA. to Jtar Nao- 11). k. I. Ii.iiii youi .uuifc (.1 *\\\i jsjibawioi Jit UfiLuJi jS' )> *iitl 4'>' 4J'- *rh« mofi fouttirm |>tft of dtf Oiailt .if Manti: :r io'* 4('. 'I'hr iiLnhrmrput of fhr currcm JireCUy ro irn muui i.l N'lituAtt i> Kli 111 jIjuui UtituJi. j$ ' J./'. U)r oUrrvinK thcfr .Jirr.-),.,.,. ^..,1 I,. ..in,. ),..., — „.),.. .1 — ,^ ■nil tlir Il1j.1l*. llir paJIj Kcw-Vork, UtUwun. - tJi f..r r.. >M„ will tuvt 'I I"' ■■■ ilur i;..l,'i. Mi. ,u,. \Ui,,,^, ii t., j'.uiUiiu: ''' " f" to the li)uiln*^il. and ivUI>y i( At ihc tAir uf 6j nr ;o nuUt j Jaj. Alulc'tiwnbcini- >. it* (ourlc. I> >i^rN>. uruju, ni.~ (han« tiiiK ».< ti.r^iiy j< A It I >ii);ii iiijy I tin- WAiiiilh ii( tlu t\ thf witcr iM\ (.1, ' »t.-l>v»rd, lit thyui.; *» putribU. .1 with i -juitc I ft. .XI atquunicd witli llu'i ^'i'Ijii^I 10 BoAuo in At ■.i(( from Uolluu ■-■^/'y n^ PARTRIDGE avitii two HEARTS. 23^ fer him all thofe which we meet with. It increafes the mafs of human knowledge, and enriches a ftore-houfe which is very precious to man; a ware-houfe belonging to all nations and to all ages. Not to lodge every new difcovery in this common ftore, is to i'quander away riches ^vhich we held only in truft, and in w hich the moft di- flant generations have an intereft. This is criminally de- priving humanity of a bleffing which is intended for the good of fociety. The foregoing refledlions induce me to publiih the following fa£t. Monfieur Verge, fenior furgeon of the artillery, lodged next door to me, and came into my room, with the entrails of a partridge which he hadjufl: opened, and {hewed me two hearts attached to one lung by blood veflels. I requefted him to go immediately to the chev. de Chaftellux, knowing that the phenomenon would be interefting to him. But wifhing firft to ftep home, and not being able with one hand to open the padlock which faftened his door, he put down the faucer which contained the entrails; his dog who had followed, fuppofing it was a mei's for himfelf, foon emptied the faucer. The chevalier de Chaftellux called on me an hour after- wards to fee a male opoffum, of which I fpoke to him on account Offrons lui done tous ceiix que nous rencontrons, c'eft groflir la malTe desconnoilTances humai- nes, et ciirichir le magazin le plus prccicux a rhomine, magazin qui apparticnt a toutes les na- tions et a tous Ics fiecles. Ne pas i ajiporter a ce deput commim les faits nouveaux que Ton de- couvre, c'eft perdre des ri^ht-fles dont on etoit depofitaire, et fur lefquelles les generations les plus reculees avoient des droits. C'eft le rendre coupable envers I'humanite, en la fiuftrant d'un hien dont on lui etoit comptable. Cc font ces reflexions qui m'engagent a rendre publique le fait fuivant. I^e Sieur Verge, chirurgien major de I'artillerie, loge a cote de chez moi, entra il y a quel- ques jours dans ma chambre, tenant dans fes mains les entrailles d'une perdrix qu'il venoit d'ouvrir, et m'y fit remarquer deux coeurs qui tenoient a im mcme poumon par des vailleaux funguins. Je le priai d'aller fur Ic champ les faire voir .i Mr. le Chevr. de Chaftellux, que je favois que ce phenomcnc inttrcfleroit. Mais ayant voulu auparavant rentrer ciiez lui, et ne pouvant d'une main ouvrir le cadenat qui fernie fa porte, il pofa a tcrre la foucoupc fur la quelle etoit-nt ces entrailles. .Son chien, qui I'avolt fuivi, crut que c'etoil pour lui, et cut bientot vide la foucoupe. Mr. le Ch-vr. de Challellux vint une heure aprcs chez moi, voir un opoffum male, dont je lui avois parle a cauTe dc la Cngularite des organcs de la generation de cct 352 PARTRIDGE WITH two HEARTS. account of the fingularity of his organs of generation^ I mentioned to him the two hearts, he could not compre- hend me. I fent to afk of the fenior furgeon why he did not do what I requefted of him ; he came and related the accident of the faucer. The chevalier de Chaftellux judged there was no other way of repairing the lofs but by a certificate, ftating what we had feen; but every thing confpired againft the defire the chevalier de Chaftellux and I had to perpetuate the phenomenon ; the dog had de- prived us of the monument; the mafter refufed us his certificate, faying, one cannot be too circumfpedl in affirm- ing a fa£t which we ouL^ht not to judge of from external appearances ; but to be convinced that that which appeared to us as two hearts were really fo, they ought to have been difle£ted, &c. One cannot too much applaud the fcruples of Mr. Verge ; but regarding as much my veracity as Mr. Verge his, I am not afraid to hazard an exadt relation of what I have feen, without alteration or exaggeration. I faw, then, two flefhy fubftances of a brown violet colour, of an oblong form, thicker at one end than the other, nearly round taken tranfverfely. Thefe two fubftances refembled each cet animalf . Je lu! parlai des deux coeiirs; il ne fcut ce que je lui voulois dire : J'envoyai de- mander au chinirgeon major pourquoi il n'avoit pas execute ce que je lui avoit dit ; il vint nous raconter I'accident de la foucoupe. Mr. le Chevr. de Chaftellux jugea qu'l n'y avoit pas d'autrc moyen de rcparer cette perte, que par un proces verbal, qui conftata ce que nous avions vu. Mais tout conlpiroit contre Ic defir que Mr. le Chevr. de Chaftellux ct moi avions de pcrpetucr le fouvenir de ce phenomene : Le chien nous a prive du monument ; le maitre nous refufe fon attcftation, Ailznt, qii\n ne prut rlrc trop lircunfjira i affrmer un fait ; qu il lie faut fat juver fur ties dpfia fences exferfeurs; que pour etre iijfure que ce qui nous a paru des coeurs fujjeut reellement des coeurs, qu'il eut fallu tes avoir au-verti, tift. On ne ptut qu'aplaudir aux fentiments qui rendent M. Verge fi fcrupuleux. Mais en me piquant d aut:mt de veracite que M. Verge, -je ne trains point de la compromettre en rendant exaftement ce que j'ai vu, fans alteration et fans exageration. Or j'ai vCi deux corps charnus d'un violet brun, de forme un peu oblongue, plus gros par un bout que par I'autre, un peu plus convcxc d'un cote que de I'autre, a peu pres ronds couiidercs tranfverfalement. Ces deux corps etoient. abfolumeut femblables I'un a I'autre (b) It has nothing external except the two tefticlcs placed under the belly; the male and the female have but one orifice placed under the tail, which ferves them to void their excrements, their urine, and probably for generation. It is not known whether a penis conies out of thit orifice, or whether there is nothing but an opening of the two orifices in the a61: of copulation. f // n'a d'extcricur que deux teficules placces fous le ventre, le male et la femelte n cnt qu un orifiet place fous la queue qui leur fert a vider les excrements, les urines, et prohtiUentent a la generation. On ignore f par ce cloaque le male fort mie ver^e, on I'il ne fe fait qu un Muchement dei dtnH orifitis Ion dt lu copulatian. PARTRIDGE with two HEARTS. ^33 each other exadly in fize, form and colour. From their thicker ends came out feveral veffels, among them I ob- ferved one to each of the bodies .pretty large and paler than the rell ; a part of this velfel was faltened to the lungs in fuch a manner, that by taking hold of only the lungs, thefe two bodies in queftion were both fufpended at the fame diftance from the lungs. In placing thefe vifcera on the hand in fuch a manner that the refemblinc: fides of thefe two bodies faced each other, the veffels w^hich were fufpended appeared uniformly difpofed, which makes me imagine that the two bodies were uniformly difpofed in the body ot the animals However, the above obfervati- ons being frefh in my memory, I ordered the entrails of four dozen of partridges of the fame fpecies'', jufl: taken out, to be brought me; and I found in each a body like the double body which had been found in the bird of Mr. Verge, having fimilar veffels, fome of which were paler than others, adhering in the fame manner to the lungs, and this body was certainly a heart or my partridges had none. I neverthelefs leave every one at liberty to judge U u which rautrc, en volume, en forme, et en couleur; dc leur gros bout fortolent plufieurs vaifTeaur, parmi lefquels j'en rcmarquai un a chacun de ces corps, alsez gros et de couleur plus pale que les autres ; une partie de ces vaifleaux tenoient au poumon, de manicre que faiUirant ieulc- Itient le poumon, les deux corps dont ii s'agit y reftoient fufpendus tous deux a la meme dif- tance du poumon. En arrangeant ces vifceres fur la main, de maniere que les cotes femblables de ces deux corps fe regardalTent, les vaiffeaux qui y tenoient fe trouvoient fimetriquement difpofes ; ce qui me fait juger que ces deux corps devoient fe trouver dans I'animal fimetrique- ment places'. Ellfin ayant encore la memoire fraiche des obfervations fufdites, je me fis ap- porter les entrailles de quatre douzaines de perdrix de la meme efpecef que Ton venoit dc vi- der, et j'ai vii qu'il fe trouvoit dans chacune un corps en tout femblable a celui qui s'etoit Uouve double dans la perdrix de M. Verge, ayant de pa^rcils vaiffeaux, dont un plus pale que les autres, tenant dc la meme manicre au poumon, et ce corps etoit certainement un cceur ou mes perdrix n'cn avoient pas. Je laill'e maintenant cbacun libre de juger lequel paroit le plus vraifcmblable, qu'une perdrix cut deux coeurs, ou qu'il ne s'eu trouva pas un feul dans quarante * y^^ P'^^f^'^^ quits occiipoierit Us aiux cotis du thorax^ et que Us "jtines de run s"" anajlomofoient auK art res de I autre et reciproquemertt. (c) 1 prefume that they occupied the two fides of the thorax, and that the veins of the one anaftamofed with the arteries of the other, and vice verfa. •j" Elle ejl un peu plus petite que celle quon appelle en France perdrix de p2>7 he evidently favv the water defcend, very contrary to his former opinion concerning thele bodies. Mr. Samuel Spring, of tlie lame town, told me that in a voyage from India, in palfing the ftraits of Malacca, a fpout fell by eftimation about fifty yards from their fliip; the appearance of which was that of a column of water; or rather a ftream of almoft contiguous drops, from the cloud down into the fea, making a great froth in the place like water falling among rocks, as he expreffed it. He faid it was extremely plain that the water defcended. One of the iliip's crew was with him when he gave me this account, and confirm.ed it. Many other accounts I have had from thofe who have feen fpouts, but fo indeterminate as not to be worth much notice; I therefore content myfelf with the above, which fpeak for themfelves. In the next place I fhall make a few remarks on Mr. Stuart's figures of fpouts, which he took in the Mediter- ranean, as they are to be feen in the philofophical tranf- adions of London, Le Motte's abridgement ; particularly on the pointing to the place of fpattering in the water, and the great roar that attends the operation of a large fpout ; the bufh about the foot or bale of a great fpout; the break or partition in the trunk of it at the top of the bufh; and the pillar-like appearance within the bufh. tirff I fhall endeavour to give fome idea of the nature and caufe of the pointing by the external and apparent means that nature ufes in the produftion of a fpout; for as to the intimate operations of nature our faculties can- not reach them. Two or three obfervations I fuppofe will readily be granted, and fhorten my work. One is that thofe places where the lower region of air is drawn away on one or both fides, either by the heat of neighbouring continents, or in the calm latitudes, from which itpalles away into, and for the fupply of the equa- torial 338 CONJECTURES concerning torial expence, are likely to be the places moft liable to fpouts. In the next place I exped It will be granted that the air is much colder in the upper regions, and of confequence fpe- cifically heavier than that near the furface, by which when there are little or no differing motions of the air, (i. e. winds) in or about the region of the clouds, particular fpots of air and vapour in the cloud, may be difpofed to defcend, and, when fo, will take very aptly a particular channel downwards. Thefe things being granted what is of a like kind will readily be fo difpofed too, as when the atmofphere is full of vapours condenfing into clouds, this condenfation may be quicker in one place than in another, which by the acquired cold will become more weighty and prefs moft in a particular point. Thus it may defcend through the more rarified and yieldingfubjacent region, the firft drops piercing and making a channel may facilitate the defcent of the vapour, till it puts on what Stuart calls a fword-like appearance. The agitation caufed by defcend- Ing will accelerate condenfation, which together with the drops paffmg through the vapour in this channel, may at every ftop in the paffage be wailing the vapour, by taking it up into lefl'er malfes of water till it ends in a point, which it will in this cafe naturally do, becaufe the fwifteft motion down is in the center of the pointing body. Such a fpout may increafe fo as to form mafles of wa- ter, the fubftance of the cloud, all obftacles removed, paf- fmg down in greater abundance, and ftill more fwiftly condenfing; or it may prefently ceafe when it has but juft appeared, or inftead of this, make, as it were, feveral at- tempts for completing a fpout, the vapour teat advancing and retiring alternately, but which finally fail, without producing effedt. Thus it has done, as it feems, when the cloud has not had fufficient fupplies for it to fucceed in a complete and opaque Ipout. Such are the appear- ances of Mr. Stuart's figures, &c. The obliquity of the pointing WIND AND WATER-SPOUTS, &c. 339 pointing is owing to the coiirfe of the air, as the bend is to two different ones at different heights. The next thing propoled to be coniidered, was the great roar that attends a complete ipout while it lafls; and it is the fame as that in catarads or falls of water from great eminencies. This kind of roar coidd not exift in any- way of afcent, being very different from that of a whirl- wind, which is no other than that of any other (Irong wind. Mr. Stuart's figures of the great fpouts are drawn with the appearance of a bufh round their bafes : The cafe is fuch, that great falls of waters muft make a proportion- able fpray ; fo that the appearance is natural, and indeed a necelfary confequence. It riles up from the foot of the fpout and falls back in a parabolic manner into the fea. As was faid of the roar jufl now, fo it may be faid of this, that it could not have exilled in any conceivable way of afcent ; while on the contrary it is perfeftly agreeable to nature on the principle of defcent. It continues the whole time of a large fpout, increafing and diminifhing as that does. The appearance of a break or partition in the trunk of the fpout, at the top of the bufh, is a very curious phe- nomenon : It is not real but apparent, and could not have happened without the bufh ; it being caufed by a refrac- tion of rays from the drops that conflitute the top of the bufli; whence a divergency and fo much lofs of viiion. In great fpouts there is alfo a pillar-like appearance, be- ing a part of the trunk within the bufh, and by another refraction through the fide of the bufli ; by which it ap- pears much bigger than it is, and limited in altitude by the break. The three lafl: are agreeable to the laws of optics; and all the five ^xirticulars being attendants on the greater or the fmaller fpouts, are to me undeniable evi- dences of the univerfal defcent of waters in thefe bodies. 1 pals from Mr. Stuart's figures to that of Mr. Maine, which is not lefs curious. Mr. 340 CONJECTURES concerning Mr. Maine, in the fame philofophical tranfadlons, has given us the figure of a fpout that fell at Topfliam, near Exeter. He has depi£lecl it in the aft of flriking a boat as it paffed a creek ; from the bottom of which he has drawn a rebound of the whole body of the fpout projefted from it to a large diftance ; evidently proving the defcent : And which, while he is arguing for the afcent, it would have much become him to have accounted for, and to have fhown how it agreed with the do£lrine of afcent. The fpout proceeding paffed on to the land, and brake off the limbs of a tree, beat the thatch off of a houfe, and did perhaps various other damage ; but we hear nothing of its carry- ing up any of the light fubftances and dropping them at great diftances, far from any environs of the place, which it would moft certainly have done had there been a whirl- wind, or any fupernal fudlion employed in the operation. The fupernal fudlion which fome have mentioned I fuppofe I may pafs over without more than the bare mention of it, but whirlwinds we know there are fre- quently, and fome of confiderable ftrength ; fo that it be- ing the general opinion that fpouts are formed by them, it may not be amifs to examine a little what force they may reafonably be allowed to have, and the limits of it. Their genuine caufe, fuppofmg them to be natural pro- du£tions, is no other than the afcent of the heated and confequently lighter air, at the furface, into, or through the colder and confequently heavier regions of the atmof- phere above : And in proportion to the different degrees of heat in one of thefe, and cold in the other, may the ftrength of thefe be, but no more. Dr. Arbuthnot, in his treatife on the air, tells us, that the rarification of the air in the hotteft day in fummer renders it but one-tenth lighter than that of the coldeft in winter, or in words to this purpofe, if 1 remember right, for I have not his book by me. Suppofmg then the up- per region the fame at all times as the lower one in win- ter WIND AND WATER-SPOUTS, &c. 341 ter when a whirlwind happens, it cannot have any great- er force than the weight of one-tenth of the atmofphere, and confidering the refiftance to its rifing which it muft en- counter, and the fridtion by the way, not lb much ; by which the ftrength may not be equal to three feet of water. It is undoubtedly nine parts in ten too weak to make a vacuum, and having a column of water two miles high to fupport, befides the additional neceffity of ftill more force to drive it fwiftly up, would require an atmofphere two thoufand times more weighty than ours to raife water to the clouds. Mr. Stuart lays he faw the water afcend in the heart of a fpout; which feems to have been an unlucky expreffion. The bodies of large fpouts are too grofs and opaque for any one to fee to the center of them ; and no one has ever pretended to have feen water afcend in the fmall ones. His imagination therefore muft have been too ftrong for any one to confide in, lb far as was he prejudiced ; and at leaft one of his views was to prove the afcent ; which, had he underftood nature in a tolerable degree, he would have renounced. That there is a gyrating appearance in the great fpouts, feems to have been matter of obfervation ; nor is there any improbability in the thing. As air palhng up in whirl- winds, fo water, or air, palling down may gyrate; and no doubt it does. The cafe is, that fome have imagined the gyration to have been upwards : but the appearance of gyra- tion up or down may eafily deceive, as any one mav be convinced by obferving the fwift turning of artificial fcrews, in which the diredion will appear as the pcrfon is difpofed to fancy it. We are told the Chinefe failors anfwer to the queftion, what are you afraid of in fpouts, is, that they may break in their decks. Which Ihows they take them to be de- fccnts ; and their knowledge is from obfervation and ex- perience. I conclude with one fliort remark, viz. That to be- lieve water afcends in thefe bodies, to the region of the X X clouds. 342 CONJECTURES coNCERNiNa clouds, Is virtually to admit of real and effential miracle, without fufEcient proof; and contrary to every idea we can form, of a divinely wife intention. Tornados and hurricanes I take to be of the fame gene- ral nature, although differing in fome circumftances and appearances. By the term tornado, or wind-fpout, I mean a violent wind which has been obferved in thefe northern colonies a few times fince they were difcovered and fettled by our people. But perhaps no part of the terraqeous globe is en- tirely free from fomething of the like kind, as the atmof- phere is every where liable to fimilar commotions. The Spanifli term of tornado, feems to have been chiefly ufed for a violent florm at fea, of larger extent than what I am about to explain, which is of a more contracted na- ture, and confined to a narrow fphere of adtion ; fo that it requires a particular and fignificant name, fuch as wind- fpout, till a more fuitable one is found for it. Defcription of one. It begins of a fudden ; more or lefs of clouds having been drawn together, a fpout of wind coming from it flrikes the ground in a round fpot of a few rods or perches diameter, with a prone diredtion, in the courfe of the wind of the day, and proceeds thus half a mile or a mile. The pronenefs of its defcent makes it re- bound from the earth, throwing fuch things as are move- able before it, but fome fideways from it. A vapour, milt or rain defcends with it, by which the path of it is mark- ed and wet. 1 fhall produce the Inftance of that at Leicefter, a towa about fifty miles from Boflon, a few years fince, which, being more violent than ufual, may give fome idea of the thing. It happened in the month of July, on a hot day about four o'clock p. M. A few clouds having gathered weft- ward and coming over head, a fudden motion of their, running together in a point being obferved, immediately a fpout of wind ftruck the ground at the weltern end of a houfe WIND AND WATER-SPOUTS, &c. 343 houfe, and inftantly carried it away, with a negro fellow in it, who was afterwards found dead in the path of it. Two men and a woman, by the breach of the floor, fell into the cellar ; one man was driven forceably up into the chimney-corner. Thefe were preferved, though much bruifed; they were wet with a vapour or mift, as were the remains of the floor and the whole path of the fpout. This wind raifed boards, timbers, &c. and carried thera before it. A joifl: was found on one end driven near three feet into the ground. I imagine the fpout took it in its elevated ftate and drove it forceably down. By what I can learn of its procedure, it continued but three or four feconds of time in a place, pafling along with the celerity of a middling wind, conftantly declining in ftrength till it ceafed. There feems to have been fuch a gufl: as this at cape Cod, about forty years ago, of which I received an ac- count from two men who lived in the neighbourhood of the place. It came on of a fudden, and was fo violent that it threw down a young woman who happened to be in the way of it; flie was forced to lay hold on the bufties which happened to be within her reach, to prevent her being carri- ed away by it. It pafled a pond of water, and the people wondered it did not fuck up the water, as they conceived it to be a water-fpout, but it did not. The young woman was however wet with the vapour that accompanied it. Of Hurricanes^ particularly thofe of the Wejl-lndia Iflands. To account fatisfacflorily for thefe convulfions of our atmofphere, requires a greater number and more circum- flantial obfervations than we are at prefent furniflied with; fo that all that can at prefent be faid of their origin and caufes muft be very conjedlural. However, fince an at- tempt to explain them may give occafion to further and more exa£l obfervations, I ftiall proceed to off'er my pre- fent thoughts concering them. X X 2 I believe J44 COJECTURES coNCEUNrNo I believe thofe of the Weft-India illands to be owing to fome occafional obftrudion in the ufual and natural pro- cedure ot the equatorial trade. This I conje£ture from the more than ufual preceding calms. In the natural courfe of this trade the air rifes up in the line and paffes off to- wards the poles, and, in the more contradfed degrees of the greater latitudes, proves the courfe of their weftern trades t So that could this afcent be prevented through the whole circle of that zone, there would be no more wefterly winds in thefe latitudes than any others. Over violent rains and cold naturally tend to check the afcent of air out of this circle, rather making it defcend. And as there are annual rains in the equator over againft thofe iflands, and in fome years more than others, it is eafy to conceive fuch an eifetf, and the confequences. Great clouds and over-much vapour generate cokl and weight,. while at the fame time the rains are beating down the air ; and as thefe prevent the rifmg of the air out of the line, fo they hinder its uiual progrels to it from the tropics on both fides. Thus calms muft take place ; by which the natives ufed to predidl approaching hurricanes, without underftanding the reafon of the thing. Much of calms in the inter-tropical climates caufe ra- rifa£tions, and afcents of air into the upper regions, inftead of its being carried to the line to be difpofed of in the grand circulation of the atmofphere; this Vx^U be the cafe more efpecially among the iflands, which Increafe the heat of the atmofphere. Then by thefe afcents there will be ac- cumulations of air above, which becoming cold in the high- er regions will acquire a greater fpeciiic weight, and be dif- pofed to defcend on the firft giving way of the more rari- fied and yielding fubjacent region ; and this will be the cafe when there happens not to be fufficient motions of air in the middle region to keep fmooth and even the ftra- tums of the more and the lei's rarified regions ; and fo prevent particular portions and places frooi bending down- wards : WIND AND WATER-SPOUTS, &c. 345 wards ; and it Is this alone that does prevent it. l]y a faikire in this, a delcent once begun, the coniequences cannot be prevented: The heavy quantity above will con- tinue to deicend till all the upper cold regions are exone- rated to many hundreds of miles round ; and all their contents fhifted into the place of the rarihed and lighter air below. Such are my ideas of the caufes and operations of a hurricane in thole climates. I have only to add here, that the rains in thefe violent ftorms are, as I think, a flron'r confirmation ot the doctrine of defcent; as they are in that kind of hurricane called by lailors the Ox's Eye, on the coaft of Guinea; and the like happens under various names in different parts of our globe. Even the v^'ind in our thunder-gulk is from defcent ; the air in the cloud being rendered denfe and weighty, defcends, and flows in the di- redtion of the wind of the time, and with the more vio- lence, by the warm air at the furface giving way to it. Thefe are fometimes ftrong, but feldom attended with danger or damage. What objedions may be raifed againff thefe opinions, fhall be candidly attended to ; in the mean time there is one obje<£lion that muft be obviated, the argument being fomewhat intereiled in it. It is as follows. Having exprelfed my opinion that hurricanes and tor- nados or wind fpouts have the fame general nature, while we fse a great difparity in their magnitude and procedure; fome explanation leems necelfary to prevent miflakes ; I think a little confideration of the place, climate, and cir- cumftances may remove the difficulty. The earth is an oblate fpheroid, its diameter many miles greater at the equator than at the poles, caufed by its di- urnal centrifugal force. If this then has fo great an effed on terraqueous matter, it cannot have lei's on our air, but it any difference, rather more; efpecially if we confider, that the atmolphere makes a larger diameter, and yet re- volves 34^ CONJECTURES concerning volves in the fame time, fo that its centrifugal force muft be proportionably greater. The diurnal motion of the earth tends to throw a vaft furplus of air on the equator, by which there is probably more air between the tropics than on the reft of the globe. But this is a matter of con- jedlure not to be perceived by any fort of preflure any more than by the barometer, for reafons obvious to thoie con- verfant in the nature and effect of the feveral principles. However it might not be amifs to obferve whether there be any difterence in the height of the mercury before any of thefe ftorms. But to return. Although the air in the intert-roplcal latitudes is in the general lighter than in the remote ones, yet when the upper air has obtained a paffage downward, it being vaft in quantity, and occupying great fpace, it will be long in accelerating and pafhng down. The paflage is long, fo that it will gain a great deal of the force we find it has by the length of defcent. Neither will the middle region be difpofed to fhut up without a brifk wind in it, before the whole, even to remote regions, is difcharged through the large hiatus, as before mentioned and now repeated, to account for the duration and extent of thefe otherwife wonderful winds, with fuch unrelenting violence. Far different is the cafe of the high latitude tornados in their circumftances and their manner, although agreeing in their general nature. The centrifugal force here has extremely little effecft, unlefs to caft the atmofphere to- ward the equator inftead of raifing or increafing its quan- tity over any given place on either fide. Beiides there is the attradlion of the fun, moon, and all the other pla- nets for ever within the tropics attracting the atmofphere that way and leftening the height of the high latitude at- mofphere, which therefore may be fuppofed not a fourth fo high from the furface as that. Since then the atmofphere is vaftly lefs in height, and alfo much lefs in quantity than toward the line, the defcents muft WIND AND WATER-SPOUTS, &c. 347 muft naturally be very different. Here are no accumula- tions aloft. The quantity ready for a difcharge downward is vaftly lefs, and the palTage narrow and contracted ; and by the alinoft conftant motions of air, were there more fupplies it would foon fhut up. Befides there is little apt- nels to flow from furrounding regions by reafon of the fmallnefs of their depth, &c. And yet fo great is the fpe- cific weight of what defcends, that the firft aflault has been known to equal the greateft violence of the proper hurri- canes in their moft powerful moments. N° XLI. The ivhole Procefs of the S'llk-Worm-, from the Egg to the Cocon ; communicated to Dr, John Morgan, Phyjlci- an at Philadelphia., in tivo Letters frotn Mejfrs Hare and Skinnfr, Silk Merchants in London^ 'July ijy 1774, and February 24, 1775. ^I^j.^"'^ TT is fome time fince we were honored with your Jl efteemed letter of 27th September laft. We fhould not have delayed fo long acknowledging its receipt, if it had been in our power to have fent you before this time the manufcript you will receive herewith j but it is only lately we have been able to procure it from one of the firft houfes in Italy. It contains an exadt account of the Italian moft improved method of making raw filk. We flatter ourfelves it may prove of fome fervice to your new eftablinied manufadlorj', for whofe ufe folely we fent for it to Italy. The large quantity of raw filk that continually arrives from China every year, being moftly of a round or large fize, will a good deal interfere with the fale of yours, provided 348 Of the SILK-WORM. provided you make it of the fame ; therefore we by all means recommend your reeling yours of the finenefs of five to fix cocons, no coarfer at any rate if avoidable. And we further beg leave to recommend your giving or- ders to your workmen to be extremely careful in aflbrting the filk, obferving that all that is put into one parcel be exa£lly, if pofhble, of the fame finenefs ; for if it is not, it will very much prejudice its fale; a negledl in this par- ticular is complained of in all the filk that has hitherto been received from America. If the filk, which was very good in itfelf that we received from Georgia, had been properly afTorted, we certainly fhould have fold it i/(5 or if. per lb. better than we did. If you reel your filk fine the China filk rather promotes its fale than otherwife, as it is neceflary to have fine filk to work up with that of China. We fliall at all times be very ready to communicate to you any intelligence in our power. We are, with refped:, Sir, Your mofl: obedient fervants, HARE & SKINNER. Cha^.I. Of the Silk-Worm. THE perfon who purpofes raifing a quantity of filk- worms, and preferving good eggs, muft begin a year be- fore hand. He muft choofe a certain number of good cocons, or filk cods, the fuperficies of which, he flightly pierces with a needle and thread and firings them by fcores ; which done, he hangs them up in a convenient room, this being the moft proper pofition for them. Af- ter the moths or butterflies contained in the cocon, have eaten their way through their natural inclofure, (which is generally about four days after the cocon is finilhed*) you may ' Tt happens fometimes tlie butterfly is longer before its birth, i. e. from IJ to 30 days if the weather is chilly. They generally come out in the morning. Of the SILK-WORM. 349 anay place them on a linen cloth difpofed vertically, as againft a wall, or on a line, &c. where they couple and are joined during twenty-four hours. This over, the fe- male lays her eggs during other twenty-four hours; after "which fhe dies, as does the male ; this their fecond life, if I may be permitted the term, is only of forty-eight hours duration. When the eggs are new laid, they are about the bignefs of a common pin's head, and of a ftraw co- lour ; by degrees they become black, aflume more folidity, lollng at the fame time part of their bulk. When they are arrived at this point, you muft feparatc them from the cloth ; to efFe£l which, you muft dip them into a large pan filled with one half water and the other half wine, rather more than lukewarm ; when your cloth has foaked in this liquor a little while, you may feparate them from the cloth with a filver fpoon and dry them in n funny place, and take them away when they begin to be whitifti. When you have thus detached your eggs, you muft keep them till the next year in a cool damp place to pre- ferve them from hatching during the great heat, which would ruin the projedt. On the arrival of the fpring, you muft obferve vv^hen the mulberry tree begins to put forth its leaves, which muft be your fignal to expofe your eggs in a very warm place, that they may all hatch at once, otherwife they would only hatch by little and little, and in proportion as each individual would be arrived at the point of its natu- ral maturity. In wliich cafe the pains required to fepa- rate their different clalfes would be exceifive, not to fay impoffible. To hatch your eg !,s you muft carry them about you nine or ten days, keeping them in your bofom, or other parts near the body; in the night you may put them between the matrafles of the bed. You may like- wife hatch them by the heat of an oven, but this method is dangerous, becaufe you may poffibly burn the worm Y y contained 350 Of the SILK-WORM. contained in the egg, and thereby deflroy all your future? hopes. II. The worm is entirely black at its birth, and is about as long as an ant. He is rolled up in the egg, which other\A ife could not contain him. He preferves this black colour eight or nine days. After your worms are hatched you mufi: put them on wicker fhelvcs, which are covered firft with paper and afterwards with a bed of the youngeil and moft tender mulberry leaves; you may place feveral ranges of them in the fame chamber, one above another, provided you leave at leafi: a foot and a half between each ranae ; that the fcaffolding be in the middle of the room, and that your wicker fhelves be not too broad, but juft fo as to reach on each fide conveniently to the middle. By degrees the worm grows and requires more room. It muft be your care to thin them, and keep thofe of the fame fize as near as you can on one row; for which reafon you mufl: always leave fome fl-^elves vacant for that purpofe. The worm continues feeding during eight days after its birth, at the end of which he has three lines in length or the fourth part of an inch. He is then attacked with his firft ficknefs, which confifts in a kind of lethargic fleep for three days together, during which fpace he changes his fkin, ftill preferving the fame bulk. This fleep being over, he begins to eat again during five days, at which term he is grown to the fize of feven lines in length, after which follows a fecond ficknefs*, in every refpedl like the former. He then feeds during other five days, and is now about nine lines in length, when he is attacked with his third ficknefs; which over, he con- tinues to eat again five days more, which are followed by his fourth ficknefs, at which time he is arrived at his full growth, i. e. about fourteen lines in length and two in; diameter. He * You muft obferve that thefe fickneffcs are much longer, and laft ieven or eight days whcn> the wcathtr is cold. Of the SILK-WORM. 351 Tie then feeds during five days with a mod voracious ^appetite; after which he dildains his food, becomes tranf- parent a Uttle on the yellow caft, and leaves his filky traces on the leaves where he pafles; thefe figns denote that he is ready to begin his cocon. You muft then furnifh him with little bufhes of heath, broom or other like twigs, flicking the bundles upright in rows between the fhelves, and forcing them a little that they may not fall; he remains ftill two days to climb up the twigs, and fettle himfelf on a good place, after which he begins to lay the foundation of his lodge, and is five days in fpinning his cocon. He remains generally about the fpace of forty-feven days. III. You muft keep your worms in a dry place, flielter- ed and fhut up clofe, provided it be not too hot. If the weather be cold you muft make a fmall fire. When you furnhh them with leaves, take great care that they be thoroughly dry and ftrew them lightly over your worms. You muft obferve to take away their dung very frequent- ly. When the worms are ready to mount (in order to fpin) if the weather be ftifllng hot attended with thunder, you will fee them in a languiftiing condition; your care muft then be to revive them, which is effected thus. Take a few eggs and onions and fry them in a pan with fome ftale hog's lard, the ranker the better, and make pancake; which done, carry it fmoaking hot into the room where they are kept, and go round the chamber with it. You will be furprized to fee how the fmell revives them, excites thofe to eat who have not done feeding, and makes the others that are ready to fpin, climb up the twigs. Thefe little creatures require a great deal of care in the management; one or other muft attend them day and night; you muft be very dexterous and gentle in handling them ; and, as I may fay, the whole fuccefs depends on the care you obferve and pains you take in rearing them. The worms cannot fuifer ftrong fmells, fuch as tobacco Y y 2 and 352 Of tue SILK-WORM. and the like, for which reafon you muft avoid offending; their delicate organs. In many parts of Italy, amongft others Romagna and La Marche of Ancona, they have two lilk racoltas, or har- vefts. They keep the eggs in very cool places, and whea the mulberry tree begins to bud again (for during the ra— eolta it is ftripped of its leaves for food for the worms) they expofe their eggs to hatch. Sometimes they give- roie leaves to the young worms, when there are no young, mulberry leaves. The cocons of this fecond racolta are: rather inferior to thofe of the firft. The filk worm is ge- nerally fourteen lines in length and two in diameter and: fix and two-fevenths in circumference. He is either of a milk or pearl colour or blackifh; thefe laft are the beft.. His body is divided into feven rings, to each of which are joined two very Ihort feet. He has a fmall point like a. thorn, exadly above the anus. The fubftance which, forms the filk, is in their ftomach, which is very long;, "wound up as it were on two fpindlcs and furrounded with a gum, commonly yellow, fometimes white, not otten greenilii. When the worm fpins his cocon, he winds off a thread from each of his fpindles, and joins them, after- wards, by means of two hooks which are placed in his. mouth; fo that the cocon is compofed of a double thread. Having opened a filk worm you may take out the fpin- ~ dies which are folded up in three plaits, and on flretching them out and drawing each extremity, you may extend them to near two ells in length. If you then fcrape the thread fo flretched out with your nail, you will fcratch off the gum, which is very much like bees-wax, and performs, the fame office to the filk it covers, as a gold leaf does to the ingot of f'llver it furrounds, when drawn out by the wire- drawer ; the filk then remains of a pearl colour. This, thread which is extremely flrong and even is about the; thicknefs of a middling pin. Three things very remarkable in this infed, are, I. They Of the SILK-WORM. 3:^3] 1. They defcribe a femicircle in eating. 2. Their excrement has perfedily the form of a mul- berry. 3. They have no fex before their metamorphofis. Chap. II. Of the Cocons. I. IT is ahnoft a general rule to wait fix or feven days after all the cocons leem to be formed, before you take them off the boughs in order to give the worms time to bring them to perfection. It is then proper from that time to give fome air to the room in which you have kept them, in order to diffipate a confiderable dampnefs which the- worms exhale on their mounting, (when they have not been well fed and kept, for when they have been proper- ly nurfed this dampnefs is not to be found) and which is of great detriment to the cocons, either by rotting them, rendering them foft, or covering them with fpots. The cocons may be divided into two general claffes, the white and the yellow, in the yellow you meet with all the fhades from a bright yellow diminlihing at laft to white,, ibme few are of a pale green. We reckon nine forts of Gocons, viz. 1. The good cocons are thofe which are brought to their perfection, ftrong and little, and not at all fpotted. 2. The pointed cocons are thoi'e, one of whofe extre- mities rites up in a point. After having afforded a little filk, the point, which is the weaker part, breaks or tears, and it is impoffible to continue winding that cocon any longer, becaui'e when the thread comes round to the hole it is of confequence broke. 3. The cocalons are a little bigger than the other, yet they do not contain more lilk, becaufe the contexture is not fo ftrong. In winding they are to be feparated from the reft, becaufe they require to be wound in cooler water, other, vile they furze out in winding. 4. The 354 Of the SILK-WORM. 4. The dupions, or douple cocons, are fo called becaufe they contain fometimes two and fometimes three worms, who have jointly formed one fingle cocon. They inter- lace their threads, for which reafon they are to be kept afunder from the reft; they make the filk we call dupions. 5. The foufflons are cocons very imperfed, whofe con- texture is loofe, fometimes to that degree that they are tranfparent, and bear the fame proportion to the others, as a gauze to a fattin. Thefe cannot be wound. 6. The perforated cocons are fo called, becaufe they have a hole at one end, for which reafon they alfo cannot be wound, 7. The calcined cocons are thofe whofe worm, after the formation of the cocon, is attacked with a ficknefs which fometimes petrifies it, and at others reduces it to a fine white powder, without in the leaft endamaging the filk ; on the contrary, thefe cocons produce more filk than the others, becaufe the worm is confiderably lighter. They are to be diftinguifhed by the noife the petrified worm makes when you fliake the cocon. In Piedmont they fell for half as much again as the others. It is very rare to fee a parcel of 25 lb. of them at a time : 6t^ lb. of thefe cocons have produced i lb. i oz. of fine filk of five to fix cocons. 8. The good choquette confifts in thofe cocons whofe worm dies, before he has brought it to its perfedion. They are to be known by the worms fticking to one fide of the cocon, which is eafily to be perceived when on fhaking it you do not hear the chryfalis rattle. Thefe cocons are of as fine filk as the others, but they are to be wound feparately becaufe they are fubjed to furze out, and the filk has not fo bright a colour, neither is it io firong and nervous. 9. The bad choquette is compofed of defedive cocons, fpotted or rotten. They wind many of thefe cocons to- gether. It makes a very foul bad qualified filk of a black- iih colour. II* To Of the silk-worm. 3jj 11. To know whether a cocon be good or not yoii muft ob- fcrve if it be firm and found, or not, if it has a fine grain, and if the two ends are round and ftrong. The cocons of a bright yellow yield more filk than the others, becaufe they contain a greater quantity of gum; but the advan- tage accrues to the winder only, becaufe all this gum is loll in the dying. For which reafon, as well as tor cer- tain colours they take better, the pale filks are preferred, becaufe having lefs gum they lofe lefs in boiling. In the number of cocons that are bought, there ought to be neither fouffions, nor perforated cocons ; becaufe the feller is obliged to keep them apart and to fell them as fuch; notwithftanding which, you may always reckon on half profit of thefe forts that remain with the others, and if to thefe you add the dupions and choquette, you may calculate them at ten per cent. The cocons of the mountains are better than thofe of the plain ; there is a greater quantity of white amongft them. 'Tis true they are not fo large as thofe of the plain, but the worm, at the fame time, is proportionably lefs. The reafon of which is, that the air of the mountains be- ing fharper, the worm labours with greater vigour. They fucceed, likewife, better in the dry plains than in the damp and marfhy parts, becaufe the leaf is more nourilliing. Five or fix days after the cocon has been detached from the branches, it is your bufinefs to prevent the birth of the worm, who would, otherwife, pierce through the fliell, and thereby render the cocon ufelefs. To prevent which you muft put your cocons in long fhallow bafkets, and fill them up within an inch of the top. You then cover them ■\ ith paper and-a wrapper over that. Thefe bafkets are to be difpofed in an oven, whofe heat is as near as can be that of an oven from which the bread is juft drawn after being baked After your cocons have remained therein near an hour, you muft draw them out, and to fee whether all the worms are dead, draw out a dupion from the 356 Or THE SILK-WORM. the middle of your bafket and open It, if the worm be dead, you may conclude all the reft are fo ; becaufe the contexture of the dupion being ftronger than that of the other cocons, it is confequently lefs eafy to be penetrated by the heat. You muft obferve to take it from the middle of the bafket, becaufe in that part the heat is leaft percep- tible ; after you have drawn your bafkets from the oven, you muft firft cover each of them vpith a woolen blanket or rug, leaving the wrapper befides, and then you pile them one on the other. If your baking has fucceeded, your woolen cover will be all over wet with a kind of dew, the thicknefs of your little finger. If there be lefs. It Is a fign your cocons have been too much or too little baked. If too much baked, the worm being over dried, cannot tranfpire a humour he no longer contains, and your co- con is then burnt. If not enough baked, the worm has not been fuffidently penetrated by the heat to dlftll the liquor he contains, and in that cafe is not dead. You muft let your bafkets ftand thus covered five or fix hours if poffible, in order to keep In the heat, as this makes an end of ftlfling thofe worms, which might have avoid- ed the firft impreflion of the fire. You are likewife to take great care to let your cocons ftand in the oven the time that is neceflary ; for If they do not ftand long enough your worm is only ftunned for a time and will afterwards be revived. If on the other hand, you leave them too long in the oven you burn them, many inftances of thefe two cafes are frequently to be met with. It is a good fign when you fee fome of the butterflies fpring out from among the cocons which have been baked, becauie you may be certain they are not burnt. For if you would kill them all to the laft worm you would burn many cocons, which might be more expofed to the heat than that particular worm. III. Whea Of the silk-worm. 357 III. When you put your cocons into the oven, you muft be very careful in picking out all the fpotted ones, other- wife they communicate their fpots by the great perfpirati- on occafioned in them by the heat. If you have a parcel of ftrong and another of weak cocons, and you can only wind a part of them frefli (i. e. without baking) give the preference to the weak cocons, and bake your rtrong ones, becaufe the latter, containing more gum, fupport the baking much better and fufFer lefs than the weak ones. As faft as the cocons you buy are brought in, put them in balkets and expofe them to the fun, if it fliines, in cafe your oven be full, in order at lead to ftun the worm and prevent his working to pierce his cocon during that time. It is very proper likewife that they be a little in the air before you put them in the oven ; becaufe the peafants bring them in bafkets heaped one on the other, which heats them and renders them extremely foft, but the air brings them to their proper tone again. Sometimes the peafants fell you the cocons ready baked when they have been obliged to keep them fometime. It is eafy to know them, becaufe the worms when baked, being dry, make a louder noife on rattling them than when they are frefli. When your cocons are fully baked, and have flood long enough, you muft fpread them half a foot thick on broad ozier (belves, w^hich are diftributed into as many ftories as the height of the room will admit of, two or three feet diftant one from the other; taking care to turn them every day, and to change their places, for other wife there are many inconveniencies that would arife from fuch a negled:. They would become mouldy and the moths would eat them. Befides this, it is abfolutely neceflary in order to feparate the fpotted cocons, or the bad choquette, which would fpread to all the cocons that are near them, and muft be wound immediately to prevent their damaging any further. Z z The 35& Of the SILK-WORM: The building where you fpread your cocons is cairecf the Coconiere, and confifts of one or more large rooms, in which are diftributed as many ranges as you can conve- niently place, taking care that the fupporters touch nei-- ther the roof nor the wall, becaufe if there were any rats in the Coconiere they would come down the poles, and de- ftroy the cocons, they being very greedy of the worm con- tained in them. A middling cocon has about thirteen lines in its great- er diameter, by eight lines the leifer diameter, fome are larger, fome are fmaller; but this is the general fize. The dupion has generally fifteen lines great diameter by nine leffer diameter. The cocon is compofed of feveral flrata or furfaces ap- plied one on the other; notwithftanding they all commu- nicate, otherwife it would be impoffible to wind them off. It is an eafy matter to take off one or more of thefe fur- faces, the uppermoft of which is coarfer, lefs gummed, and higher coloured than the undermoft. Finally, thefe: furfaces are compofed of a fine fort of faliva, whofe tex- ture has a tolerable refemblance to the thin fkin you find joined to the infide of a hen's egg. The cocons produce a thread of a very unequal length, you may meet fome that yield twelve hundred ells, whilft others will fcarcely afford two hundred ells. In general you may calculate the produdion of a cocon, from five- hundred to fix hundred ells in length. IV. The worm or chryfalis, as he is inclofed in his co- con is fhrunk up into himfelf, fo that it is but half as long in his primitive ftate, but it is on the contrary as thick again. He is of a cinnamon colour, and full of liquor, rather clear, which forms the feed in the males, and the eggs in the females. Though he feems to be infenfibie in that ftate, yet you may perceive he is not wholly fo, for on piercing him with a pin flightly, you will fee him move. Of the SILK-WORM. 359 move, and we make ufe of thefe experiments to fee if they have been killed in the oven. The worm dries the older it grows, fo that the fame quantity, or the lame number of cocons decreafes daily in -weight. The cocons which enclofe the male butterfly have more filk at the extremities, than thofe which con- tain the females; but it is very difficult to perceive this difference, the moft Ikilful connoiffeurs will miftake at leaft twenty in a hundred. When the worm wants to break his way through, he pierces the cocon, firft wetting it a little in order to gnaw it the more eafily ; he has then only to ftrip off his upper coat, under which he has another quite white, with wings. When he comes out, his wings, which at firfl appear very fmall, open and difplay themfelves by little and lit- tle, and are entirely at liberty in an hour or two. As foon as born he feeks a female, and one would fay he is born again merely to propagate his fpecies, for he expires a very little time after having performed his fundion. Chap. III. Of Cocons Royah Perforated Cocons ^ and Soiifflons. THE royal cocons are thofe which you have kept for feed. The worm makes a hole in them for his paffage, fo that they cannot be v\'ound, and are in the fame clafs with the perforated cocons. Neither can the foufBons be wound, becaufe their thread being the produce of a weak, fick worm, it has not the gum it ought to contain. Befides they cannot be wound off, their thread being interlaced and entangled. The ufes you may make of thefe cocons are the follow- ing ; and firlt for the SoufBons ; you muft let them boil for about half an hour in common water, after which you muft dry them. When they are quite dry you muft threfh them on the Z z 2 floor :,6o Of the SILK-WORM. floor with a flail, to bring out the worm, which is reduceS to a(hes by the fire and air. Afterwards you put them, on a diflaff and open them ; to effedl which you rnuft take them by the two ends and ftretch them out at arms length, you may then faften them on your dillafF. 2. The perforated cocons ; you mufl obferve the fame method as for the foufilons, except that you muft let them boil three-quarters inftead of halt an hour, becaufe they contain a greater quantity of gum. 3. The cocons royal. As it is natural to fuppofe you keep the flower of your cocons for leed ; they are fuller of gum than the others, for which reaibn you muft let them boil an hour; after which you muft not threfti them as the former, becaufe they contain no worm, neither is it neceflary to ftay till they are quite dry before you fpin them; on the contrary, they open more eafily when damp. The produce of thefe three forts of cocons, when worked,^ makes what we cMJ/ei/ret. After you have boiled the cocons and threftied them ■well, to Ifiake out the worm they contain, you may card them inftead of opening them as above, you will then make a much more beautiful fleuret, and of a brighter colour, but it will at the fame time come confiderably dearer, becaufe ot the wafte in carding. A good fpinfter performs a very reafonable days work if flie can fpin an ounce of fleuret. To fum up the whole, and give you a notion of the va- lue of thefe three forts of cocons, you may calculate thus. If the good cocons are worth one hundred, the perfo- rated are worth thirty-three one third, the foufflons twen- ty-five, the royal cocons two hundred and fifty; but if your royal cocons are not chofen ones for feed, they are ■worth but two hundred. The beft fleuret is that which proceeds from the royal cocons, afterwards that of the perforated cocons unchofen, laft of all that of the foufflons. CHAPr Of the SILK-WORM. j6r Chap. IV. Of the Filature^ or Winding from the Worm. Although the frefh cocons, that is to fay, thofe that have not been baked in the oven, yield a brighter filk than thoie that have, and at the fame time yield better weight, by realon of part of their gum which they have not loft by the tire, yet moft people prefer thofe that are baked, in order to have a filk more even in its colour; unlefs you could have a confiderable quantity of frefla cocons, and time to wind them fo; for otherwife it is undeniable, that the trelli would be much more advantageous, as well for the reafon above mentioned as becaufe they are eafier to wind, not having been dried by the fire. Before you begin to wind, you mufl; prepare your co- cons as follows. 1. In ftripping them of that wafte filk that furrounds them, and which ferved to fallen them to the twigs. This burr is proper to fluff quilts, or other fuch ufes; you may likewife fpin it to make Ifockings, but they will be coarie and ordinary. 2. You muft fort your cocons, feparating them into different clafles in order to v\ ind them apart. Thefe claf- fes are, The good white cocons. The good cocons of all the other colours. The dupions. The cocalons, among which are included the weak cocons. Tne good choquette ; and, laflly. The bad choquette. In forting the cocons, you will always find fome per- forated cocons amongft them, whofe worm is already born; thole you mufl let apart for fleuret. As I have de- fcribcd above, you will like>vife find fome foufHons, but very few ; for which reafon you may put them among the bad choquette, and they run up into wafte. The 362 Of the SILK- worm. The good cocons, as well white as yellow, are tlie eafieft to wind ; thole which require the greateft care and pains are the cocalons; you muft wind them in cooler wa- ter than the others, and if you take care to give them to a good windfter, you will have as good filk from them as the reft. You muft likewife have careful windfters for the dupions and choquettes. Thefe two articles require hotter water than the common cocons. The good cocons are to be wound in the following man- ner. Firft choofe an open convenient place for your fila- ture, the longer the better, if you intend to have many furnaces and coppers. This building fhould be high and open on one fide and walled on the other, as well to fcreen you from the cold winds and receive the fun, as to give a free paffage to the fteam of your bafons or coppers. Thefe coppers or bafons are to be difpofed (when the building will admit of it) in a row on each fide of the fi- lature, as being the moft convenient method of placing them, for by that means in walking up and down you fee what every one is about. And thele bafons fliould be two and two together, with a chimney between every couple. Having prepared your reels, (which are turned by hands and require a quick eye) and your fire being a light one under every bafon, your windfter muft ftay till the water is as hot as it can be without boiling. When every thing is now ready, you throw into your bafons two or three handsful of cocons, which you gently brufti over with a wiflc about fix inches long, cut ftumpy like a broom worn out : by thefe means the threads of the cocons ftick to the wifk. You muft diiengage thele threads from the wift?:, and purge them by drawiuic thefe ends with your fingers till they come off^ entirely clean. This operation is call- ed la Battiie. When the threads are quite clear, you muft pafs four of them i^if you will wind fine filk) through each of the boles in a thin iron bar that is placed horizontally at the edge Of the SILK-WORM. ^6^ cJge of your bafon ; afterwards you twift the two ends (which confift of four cocons each) twenty or twenty-five tunes, that the tour ends in each thread may the better join together in crolhng one another, and that your filk may be plump, which otherwife would be flat. Your windfter muft always have a bowl of cold water by her, to dip her fingers in, and to fprinkle very often the laid bar, that the heat may not burn the thread. Your threads, when thus twifted, go upon two iron hooks called rampins, which are placed higher, and from thence they go upon the reel. Now at one end of the axis of the reel is a cog-wheel, which catching in the teeth of the poft-rampin, moves it from the right to the left, and confequently the thread that is upon it ; fo that your filk is wound on the reel crofs-ways, and your threads form two hanks of about four fingers broad. As often as the cocons you wind are done, or break or diminifli only, you mufl join frefh ones to keep up the number requifite, or the proportion ; 1 fay the proportion, becaufe as the cocons wind off, the thread being finer, you muft join two cocons half wound to replace a new one : Thus you may wind three new ones and two half wound, and your filk is from four to five cocons. When you would join a frefh thread, you muft lay one end on your finger, v\ hich you throw lightly on the other threads that are winding, and it joins them immediately, and continues to go up with the reft. You muft not wind ofl^ your cocons too bare or to the laft, becaufe when they are near at an end, the bairre, as we call it, that is the hufk, joins in with the other threads and makes the filk foul and gouty. When you have finiftied your firft parcel, you muft clean your bafons, taking out all the ftriped worms, as well as the cocons, on which there is a little filk, which you firlt npen and take out the worm and then throw them in- to a bafliet by you, into which you likewife caft the loofe filk that comes off in making the battije. You 364 Of the SILK-WORM. You then proceed, as before, with other two or three handsful of cocons ; you make a new battue ; you purge them, and continue to wind the fame number of cocons or their equivalent, and fo to the end. As I faid above, your windfter murt always have a bowl of cold water by her, to fprinkle the bar, to cool her fin- gers every time fhe dips them in the hot water, and to pour into her bafon when neceffary, that is, when her wa- ter begins to boil. You muft be very careful to twift your threads a fufficient number of times, about twenty-five, otherwife your filk remains flat, inrtead of being round and full; befides when the filk is not well crofiTed it never can be clean, becaule a gout or nub that comes from a cocon will pafs through a fmall number of thefe twirts, though a greater will ft:op it. Your thread then breaks and you pafs what foulnels there may be in the middle of your reel, between the two hanks, which ferves for a head band to tie them. You muft mind your water be juft in a proper degree of heat. When it is too hot the thread is dead and has no body ; when it is too cold, the ends which form the thread do not join well, and form a harlh ill-qualified filk. You mufl change the water in your bafon four times a day, for your dupions and choquette, and twice only for good cocons when you wind fine filk, but if you wind coarfe filk it is neceflary to change it three or four times. For if you was not to change the water the filk w^ould not be fo bright and gloily, becaufe the worm contained in the cocons foul it very confiderably. You mufi: endea- vour as much as poflible to wind with clear water, for if there are too many worms in it, your filk is covered with a kind of duft, which attrad;s the moth and deftroys your filk. You may wind your filk of what fize you pleafe, from one coGOn to a thouland; but it is difficult to wind more than thirty in a thread. The nicety, and that in which confirts Of the silk-worm. 36^ confifts the greateft difficulty, is to wind even, becaufe as the cocon winds ofF, the end is finer, and you muft then join other cocons to keep up the fame fize. This difiicuky of keeping; the filk always even is fo great, that (excepting a thread of two cocons, which we call fuch) we do not fay a filk of three, of four, or of fix cocons, but a filk of three to four, of four to five, of fix to feven cocons. If you proceed to a coarfer filk you cannot calculate fo nicely as to one cocon more or lefs. We fay for example, from twelve to fifteen, from fifteen to twenty, and fo on. It is eafy to conceive, that it is more difficult to wind a coarfe filk even, than a fine one, becaufe it is harder to keep a great number of cocons always to the fame fize, than a fmall one. The dupions which you defign for rondelette, or ordi- nary fewing filk, are to be wound from fifteen to twenty. The reft you may wind as coarfe as poffible, i. e. from forty to fifty : they ferve to cover and fill up in coarfe fluffs, and may likewife be ufed forfome fort of fewing filk. The good choquette is to be wound according to the ufes to which you intend to apply it ; however not finer than from feven to eight. The bad choquette you may wind from fifteen to twenty cocons. In winding the good cocons, you will always meet with fome defedlive, which will not wind off, or are full of gouts and nubs. Thefe you muft take out of your bafon and keep by themfelves. They are called bajftnats. They are to be wound apart as coarle as you can. They make a foul, dirty filk. To have a good filk, you muft wind ia fine weather. If the wind be hi^h it fhakes your filk, and prevents its lying fmooth on the reel, forms ftrings of threads, which make it very difficult to wind on bob- bins. If the weather is rainy the filk is damp, and has not that luftre it ought to have, or which it has when it dries, as it goes upon the reel. You muft mind not to hank it when damp, but let it dry on the reclj otherwife it would be furzy. A a a I have 2,66 ANATOMICAL PREPARATIONS I have now only to fpeak of the wafte that comes from the battue, and the hulks of the cocons, that have llili fome filk upon them, which are thrown into bafkets in winding, and are what we call morefques. Thefe you firft dry in the fun, then threfh, and afterwards card and fpin them to make fleuret. One hundred and fifty ounces of good cocons yield about eleven ounces of filk from five to fix cocons ; if you wind coarfer, fomething more. You may wind about eleven or twelve ounces of filk from five to fix cocons in fourteen hours. The filk which is made of baffinats and bad choquette ferves to make ftockings and coarfe heavy fluffs, fuch as fattinades and damafks for hangings, &c. &c. N° XLII. The Art of making Ajiatamical Preparations by Corrojion. By John Morgan, M. Z). ProfeJJbr of the Theory and Pra^ice of Phyfic in the Univerfity of Pennfyl'uaniay Member of the Royal College of Phyftcians at Edinburghy and F. R. S. at London^ 6'^- AS no branch of fcience more certainly leads to an in— timate acquaintance with the fundlions of the ani- mal body, (which is the foundation of all rational know- ledge of the caufes and cure of difeafes) than that of the ftruiture of the vafcular fyftem, the origin, divifions, dif- ferent ramifications and numerous inofculations of the veffels into, and their communication with each other, I have always thought this field of ufeful information de- ferved to be cultivated with great induftry and attention. In effe£t it brings us immediately, and in the moft com- pendious way, to acquire a knowledge of the nature, and of the motions of the fluids which circulate through them, of their dillribution throughout the diiferent parts of the body, By C O R R O S I O N. 367 body, and of the a£tion and ufes of the veflcls containing, as well as of the humours contained in them. In parti- cular, it behoves every pradtitioner of phyfic to ftudy the vaicular texture and compofition of the vifcera, for upon their healthful adlion the continuance of life, free from difeafe, principally depends; and the more their fuhdions are injured, the more dangerous difeafes are thereby ge- nerated. From a relaxation of them arife atonia and w^eak- nefs, and from obftrudtion of them infarctions, inflamma- tions, tumors and fchirri are produced. To an acquaint- ance with their ftru£ture and anaftomofes, and the fluids they carry, we muft be chiefly indebted for our knowledge of the dodtrines of refolution and fuppuration, and for the indications that point out to the phyfician by what means to accomplilb thefe defirable events, according to circum- ftances. The little progrefs which pradtical anatomy has hitherto made in America, and the great confequence it may be of to the riling fliudents of phyfic and furgery, to employ more of their attention on this ufeful fubjedl, are my mo- tives for laying before you this eflay, in hopes through this channel to ftir them up to profecute it with more zeal and ardor. This becomes the more neceflary, becaufe, owing to the late revolution, the fubjeds of North-America having eftablifhed themfelves into independent ftates, have at prefent leis commerce and lefs intercourfe with the learn- ed and poliflied nations of Europe. At leafl; fewer ftudents from America have recourfe to them for improvement in the knowledge of their profefTion than formerly, in as much as medical fchools and colleges have been founded in feve- ral of thefe different ftates, fince the author of this eflay firft recommended and aflifted in carrying into execution the plan of tranfplanting phyfic, as a fcience, from acrofs the ocean, by inftituting medical fchools on this weftern fide of the Atlantic*. A a a 2 Upon • See his difcourfe on the inflitution of medical fchools in America, delivered at a pub- lic conuiicucement in the college of Philadelphia, May 1765. 368 ANATOMICAL PREPARATIONS Upon our own exertions mufl: we therefore chiefly de- pend for building up the medical fabric, erefling ufe- ful temples of the healing arts, and diffufing the lights we can kindle through this new world. I know no one ftep that can be more ufeful to accomplifli this undertak- ing, than to teach the art of inveftigating the ftrudlure of the different parts of the animal body, by injed:ions and corrofions, and other preparations of wax. Such is the prefent ftate of anatomy in this country that there are at prefent but very few, I believe I may fay no fuch preparations worth mentioning to be met with here, that have been made in America. Do£tor Chovet, now refident in this city has indeed a good collection of wax preparations, of different parts of the human body, which he made in his younger days and brought hither from Europe. But nothing of this kind has hitherto been pradifed, or it has been fo taught as never to have been of lading ufe to any that I know of. Being well acquainted with the general defire that fills the breafts of my countrymen, to acquire and improve every kind of fcience that is ufeful, which is properly laid before them, I truft this attempt will ftir up many to learn and pra£life thofe leffons which, for their particular benefit, I now unfold to them ; nor do I doubt in a little time but we fliall fee fuch an emulation kindled for improving on thefe hints, that all kinds of ufeful preparations will befo common after a while, as not only to give rife to anato- mical cabinets and repofitaries for fpecimens of the ani- mal, vegetable and foffil kingdoms, as will tend to throw great light upon philofophy in general, but contribute to lay a folid and ufeful foundation of natural hiflory in America. The firft rudiments of this art that 1 acquired was from the two Hunters, known through all Europe for their fuperior flvill in anatomy, and adling as pradical dif- feftor to the celebrated dodlors Colignon and Smith, pro- felFors of anatomy in the univerfities of Cambridge and Ox- ford, By C O R R O S I O N. 2>^->iy ford, which I further improved by praftice at Paris with Monf. Sue, to whom I am wholly indebted for my know- ledge of anatomical preparations in wax. The kind of preparations of thofe parts of the animal body which admit of it that I now propofe to explain, namely by injection and corrofion, exceeds in beauty, nicety and ufefulnefs, that which is commonly called dif- fe£lion. In fa£t, in this latter, we can trace nature but very im- perfeftly, becaufe by difledlion, the larger vefl'els only are preferved from the knife, and for the moft part all the fmaller are unavoidably cut away. On the contrary, in anatomical preparations by corrofi- on, even the very fmall veffels may be kept entire, and we can fee, at a caft of the eye, the courfe and diftributi- on of all the vafcular fyftem even to the fize of an hair, called capillary veffels, and thofe too difengaged from the furrounding parts, which otherwife wholly conceal, or make them difficult to be perceived. It is impofllble that with only the affiftance of a differing knife, any perlon fhould be able to lay open to view all thofe fmaller veffels, however flcilful and experienced the hand may be that directs it. The exadl and perfect imitation of nature which this fort of preparations prefents, the eafe with which they are made, and their extraordinary beauty and neatnefs, render a knowledge of this art fo much the more defirable. The art of injecting the very fine veffels of the body with common injedlion, was well known to the celebrated Ruyfch, the moft famous anatomiit, in that way, of any living in Europe in his day; and therefore it has been fometimes called the Ruyfchian art, but it fell fhort of the one I now undertake to explain, becaufe in his prepara- tions the minute veffels only become vifible, fo far as the fubftance through which they proceed was tranfpa- rent, but our art extends to the removal of every fur- rounding 370 ANATOMICAL PREPARATIONS rounding fubflance, and leaves them entirely naked and perfedlly expofed to the eye. I once (hewed a preparati- on of the veflels of a kidney I had thus executed at Paris, to a meeting of the French academy of furgery in the year 1764, who allowed it to be curious and quite new to them. I think none of the members prefent at that meeting, ex- cept Monf. Morand, fecretary of that academy, who had been in England and was acquainted with dod:or Hunter, alledged their having ever feen a fimilar preparation. At their requeft I prefented a memoir on the fubjedl, and fince that time Monf. Siie has beftowed one entire fedion in treating exprefsly upon it, with a polite acknowledge- ment of his having acquired his knowledge from me, on- ly with the particularity of naming me as one of the facul- ty of Edinburgh, without taking any notice of my being a Pennfylvanian by birth, or native of America, which have led fome into miftakes concerning the author of that piece. The reafon may be that Americans before the revolution, being but little confidered in any other light than as colonirts, their nation was feldom taken notice of, and I was introduced to him firft as a graduate of the univerfity of Edinburgh, and known to him afterwards as a inember of the royal college of phyficians of that place. Thefe preparations are, fince that period, become com- mon in France, and the art is now well known, and cul- tivated fuccefsfuUy by Monf. Slie and others; but it was unknown there till I communicated it, firft at Paris, and afterward in the fouth of France ; where I had the honour of explaining it to the illuftrious Monf. Imbert, chancellor of the univerfity at Montpelier, and to Monf. Bourgelas, principal of the Ecole veterenaire, or academy eftablifhed at Lyons for the improvement of the fcience of horfeman- fhip, juftly celebrated for his very elegant preparations of the anatomy of horfes, &c. But what gave me equal pleafure and furprize, was the admiration excited on my prefenting' By C O R R O S I O N. 371 prefenting only a part of the vafcular preparation of a kidney by corrofion, (the reft beuig broke down in a jour- ney by land of above a thouland miles) which was ex- preffed by the celebrated Morgagni, illuftrious profefTor of anatomy in the univerfity of Padua. He had kept up a literary correfpondence with Ruyfch when alive, had been favoured with fpecimens of this great man's prepa- rations, and declared that in comparifon to the preparation I gave him, they were " rudis indigeftaquc moles?' From this fmall fpecimen, he faid, " ex ungue leonem," he could readily comprehend that the uiefalnefs of this kind of knowledge amongft the learned in anatomy, niuft become great and exteniive. I mention thefe anecdotes merely to fliow how recent, or at leall how confined the knowledge of this ufeful art then was, being limited, as far as I know, to Great-Bri- tain only. I fuppoie it to be owing to this circumftance, viz. that real practical anatomifts who have excelled in their preparations, have too generally kept fecret the me- thods and arts they employed in making thofe preparati- ons. For this reafon, much I think is due to the me- mory of the great Profellor Monro, of Edinburgh, who has publifhed a paper upon the art of making injedlons. So far as I can learn, this art cannot be traced farther back than to the learned Dr. Nichols of London, who for- merly gave ledlures in anatomy both there and at Ox- ford, and from whom Dr. Hunter acknowledged to his pupils that he received his firft Information. He then de- ferves to be looked upon as the author and Inventor of this art. When Dr. Nichols dechned the bufinefs. Dr. Hunter and his brother Mr. Hunter, took up the profefTiou of anatomy. Without doubt, thofe unrivalled brothers in anatomical Iklll, made confiderable improvements in the art of Injeding and diffeding animal bodies ; and it is like- ly improved the compofition of injedions for corrofion. 372 ANATOMICAL PREPARATIONS My well meant intention of marking the rife and pro- grefs of this art, and of exciting an emulation in my countrymen to profecute and improve it, will, I hope, not only excule but jullify both the matter and length of my introdudtion. Thefe preliminaries being thus fettled, I now proceed to the main obje£t of this communication. Without ex- patiating upon the advantages that will attend an accurate knowledge of this art, for the fake of perfpicuity I (hall here reftridl myfelf to laying the following obfervations before you, reduced to general heads, in as few words, and in as concife a manner as I am able. They may be ufeful to thofe who wi(h to put them in practice, and will perhaps giveoccafion to perfons who are curious in making experiments in anatomy, to li.L-ht up fome new difcovery. The art of making anatomical preparations by corrofi- on, depends on the following principles. 1. We ought for the matter of injection to make ufeof a fubftance that is poflefled of a fuitable degree of confift- ence, and- fine enough to penetrate into the minuteft vef- fels, and which at the fame time has fuch a firmnefs of texture as not to alter with the changes of the temperature of the atmofphere, that is, it ought not to be fubje£t to melt with the fummer's heat, nor to break down from its brittlenefs on being gently handled in the winter. 2. The colours to be employed for fake of diflinguifh- ing the different orders of veffels, whether arterial, venal, tracheal or others, ought to be of fuch a nature as not to be changed upon applicaiion of the menRruum. 3. We ought to make ul'e of a mcnflruum that is capa- ble of confuming the mufcular, parenchymatous, cellular or fatty parts that furround the veffels, without affedling the fubflance that we ufe for injection to fill the veffels. . 4. Care and addrefs are neceffary in the perfon who makes the injection. 5. Lartly, great attention is requifite in removing the loofe and corroded parts, and in feparating them from the injcded By CORROSION. 373 inje£led veflels without breaking them down by the force applied in cleanfing them. The following directions will ferve to guide the opera- tor in thefe different manoeuvres. The common injedtions are compofed of wax and fuet, or of wax and oil ; the fuet or oil is made ufe of to foften the wax, and to give it the neceflary confiftence. We cannot employ fuch a compofition in our corroded prepa- rations, being oppofed to the third principle laid down ; becaufe the menftruum we ufe for deftroying the parts that furround the veflels, will alfo attack and confume the fat and animal fubftances which enter into the compofition of the injed:ion. But we may employ the following compo- fitions, the goodnefs whereof has been proved by repeated trials, viz. First Receip t. Take of white or the befl: yellow wax and purified rofin each equal parts, e. g. ten or twelve ounces ; melt them to- gether and add a fufficient quantity of fpirit of turpentine, to give a due confiftence, that is from fix to eight ounces. It isadvifeableto melt the rofin firft, and ftrain it through a piece of fine linen ; becaufe, in the ftate it is bought out of the fliops, it is often mixed with foreign fubftances. I am of opinion this injedlion will turn out to be finer than the following, that is, it will penetrate into ftill fmaller veflels, but it is thought to have the inconvenience of being more brittle ; fo that after corrofion, the moft flender of the veflels are more liable to break down in handling the preparation. The following is the receipt which the celebrated MelTrs Hunter of London, have commonly made ufe of. It is lefs brittle and produces a firmer cohefion of parts, with nearly the fame confiftence as the former. Befides, it en- ters very fufficiently into the capillary vefl'els. Second Receipt. Take of pure rofin eight ounces, of wax four ounces, *of Venice turpentine a fufiicient quantity, that is, about B b b eleven 374 ANATOMICAL PREPARATIONS eleven or twelve ounces, to procure a proper confiftence to the injedtion. The method of afcertaining the due confiftence and the neceflary firmnefs of the injection, is by taking up any quantity of it, whilft melted, with a fmall wooden fpatula, and then letting it fall drop by drop on the furface of cold water. This immediately fpreads and forms into a thin plate. By rolling it between your thumb and fin- ger firft moiftened, or in the palm of one hand with the fingers of the other, both previoufly made wet to prevent flicking, turn it into the fhape of a cylinder or fmall blood- vefTel, then throw it into a bafon of cold water, and let it remain till it is quite cold. If it is then of fuch a confift- ence as not to yield to a very flight force, when prelTed be- tween your thumb and finger, affd yet fo foft as to be ca- pable of bending readily without breaking, it has the due medium of firmnefs and flexibility which is defired. If it appears to be too foft, a further quantity of wax and I'ofin are to be added in the above mentioned proportion, till it acquires the wiftied for confiftence. If, on the other hand, it is too hard, a proportionably larger quantity of the Venice turpentine is to be added. The fame precau- tion is to be obferved, if we make ufe of rofin, wax and fpirit of turpentine, as directed in the firft receipt. Operators feldom are at the trouble of weighing the ingredients ; they generally judge of the refpedtive weights and proportions of each by the eye. This method of de- termining them will anfwer very well for perfons who have acquired experience j for the difl^erent feafon of the year when the injedtlon is made, and the diff'erent confiftence or purity of the wax and rofin, with other little circum- ftances which fometimes happen, occafion fome little va- riation. In general there is not fo great danger of fpoil- ing the preparation, by making the compofition a little fofter than is required, rather than harder, becaufe it grows fome what harder by time, and alfo by fteeping the By C O R R O S I O N. 375 the parts injeded in water, for the fake of wafliing off the menllruum that we have made ufe of for performing the neceflary corrofion. Thefe injedlions are well fuited to make corroded pre- parations of the vifcera, as of the heart, lungs, liver and kidneys. Yet I doubt not but perfons of ingenuity, who fhall be at the pains to render themfelves converfant in the art of inje£lion, by giving attention to every circum- fiance, will acquire further fkill and may find other fub- ftances, equally fit for injeilion without being fo liable to become brittle, which thofe compofitions I have given above are, in fome degree, even when made with the ut- moft care and exacftnefs. To know whether any fiibftance of which a perfon wifli- es to make a trial for injection, will withftand the adtion of the menftruum he means to employ, it is fiafficient to put a piece ot the compofition to be ufed as an injedtion into a fmall quantity of the menftruum, and let it remain in it for a week or fortnight; by that means he can judge of its goodnefs, before be is at the trouble of making, or of Ijpoiling an injection, as the cafe may happen. Of the Colours. The colours wc commonly ufe to diftinguifh the differ- ent orders of veffels are, ift. Vermilion for colouring the injedtion for the arteries. 2d. Blue verditure, or what is call- ed PrufTian blue, for the injection to be thrown into the veins. 3d. For colouring the injections to be thrown into the ureters and pelvis of the kidneys, and the tracheal veffels of the lungs, what are called in EngliJh king's yellow and flake white are moftly ufed. A variety of other co- lours may be employed, but thefe are the principal and the beft. We fhould obferve to melt the wax thoroughly over a flow fire, and the colouring powders fhould be added by degrees, ftirring them well in at the fame time, before the B b b 2 other 376 ANATOMICAL PREPARATIONS other ingredients are added. This method prevents any efFervefcence, which often happens when there is too great a fire, or when all the ingredients are mingled together before the colouring powders are added, efpecially the two laft. The quantity is judged of by trial. Of the proper Menstruum.. I now pafs to the third head, viz. to confider what fub- ftances will anfwer, for confuming all the parts furround- ing the injedion, and leaving the matter in the veflels themfelves untouched. The beft I have yet tried is the concentrated fuming acid of marine fait, which comes over in the diflillation employed in the procefs for making glaubers fait; it fhould not be diluted with water, nor be dulcified, other- wife it becomes too weak to anfwer the purpofe, or at leaft the time required for compleating the corrofion is thereby protradled beyond what is needful. The concentrated acids of vitriol and of nitre, are no lefs powerful to deftroy all the animal fubftance, furrounding the inje£led veflTels, but the objedion to which, from feve- ral trials, they appear to be liable, is that they are fup- pofed to crifp the veflels ; at leaft the fpirit of fea-falt has been moft ufed, and concluded to be tke leaft exception-^ able menftruum for this operation. Such were the fentiments I communicated, in my me- moir to the royal academy of furgery at Paris in the year 1764, fince which, Monf. SUe, royal profeflTor of anatomy in the fchools of furgery, and in the royal academy of painting and fculpture at Paris, having honoured my com- munication to the abovementioned academy, with a fec- tion in his treatife entitled Anthropotomie, chap. 2. fe£t. 25. from page 70 to page 84 ; after acknowledging that he received the art of making thofe preparations from me, thus adds. " Since that time my nephew and I, having worked at them a great deal, and with abundant fuc- cefs, Of corrosion. m cefs, we have difcovered, that we may change the men- ftruum, without injurhig the preparation at all, and em- ploy aqua fortis, or the nitrous acid in place of the fu- ming fpirit of fait; and that aqua fortis is even a more perfedl menftrum, than the fpirit of lalt, in as much as the colour of the injection is thereby lefs changed, and the fmall velfels better preferved. Bei'ides the difference of expence is confiderablc, as the fpirit of fait is worth eighteen livres a pint, whilft the aqua fortis cofts at moft but two livres, and the effect is the fame for quantity, I have alfo employed the fpirit of nitre for the fame pur- pofe, with great fuccefs*." In refpeB to the fourth Principle-, yiatnely, the Addrefs of the Operator., and ivherein it conftfls. He ought to guard againft cutting away or removing the cellular and other furrounding parts, before he has made the injedion. In fatt, thefe give firmnefs to the veflels, and prevent their ftretching unnaturally, or affum- ing forms contrary to nature, from the impulfe of the in- jedlion when drove into them by the hand of the anato- mift. Thefe fubflances enable them to refift the too great extenfion and yielding to the force applied. The injedling pipes ought to be proportioned to the fize of the veflels through which the inje£lion is to be made. It is proper to foak thofe parts in warm water, which we are about to injeft, for a (horter or longer fpace of time, as well to wafh them clean, as to carry off the blood and other fluids, and the better to difpofe thofe parts to receive: the inje£lion, with which they are to be filled. The- * Monf. Morgan, Doflcur en medicine de la faculte d'Edinbourg, en » donnc une defcrip- tion exacle a 1' Academic royalc de la chirurgie, tt c'eft de lui que je tiens I'art de preparer ces parties; mais depuis apres y avoir beaucoup travaiUe, mon ncveu ct moi, et y avoir eu beau- coup de fucces, nous avons decouvert qu'on pouvoit changer le menftrue, fans preiudicier on rien a la preparation, ct employer, au lieu de fel fumant, I'eau forte, qui eft meme un menftrue plus parfait, que I'efprit de fel, puifque la couleur de I'injetTion eft moins chanece et que Ics petits vaiftcaux font mieux confcrvcs. D'ailleurs la difference eft encor bien grandc pour la dcpenfe, pulfque I'efprit de fel vaut l8 liv la pinte, au lieu que I'eau forte ne coute tout au plus que i liv, et que la quantite eft la meme pour I'effet. J'ai employe aufli avcc beaucoup de fucccs I'efprit de nitre. Authropotomic, pag. 83. 84. }.- 37$ ANATOMICAL PREPARATIONS The fubftance employed for the inje£tion ought to be entirely melted over a moderate fire, and be heated to the exa£t degree that will not permit the cooling of it too faft, upon coming into contact with the parts into which it is impelled, nor ought it to be fo great, on the other hand, as to burn or crifp the veflels, or prove troublelbme to the operator in handling the fyringe or pipes, whilft he is making the injeftion. The inje£tion fhould be thrown into the part to be pre- pared, at one uniform impulfe, made flowly and evenly, with a fteady hand, and with folittleforce as not to endanger a rupture of the veflels in the loft parts. When the in- jection is finifhed, the pipes fliould be corked or otherwifc clofed, and the parts injeded fhould be fuffered to cool by degrees. If they are plunged at once into cold water, before the fubftance of them has acquired a certain de- gree of hardnefs and firmnefs, a contra£lion in the elaftic coats of the veflels may be produced, fufficient to occa- fion a rupture, efpecially in the capillaries, which will always be followed by an extravafation of the injected fubftance. Having expofed the injected parts to the air during an hour or two, it is proper to commit them to cold water all night, to cool and to harden them thoroughly. After taking them out of the containing veflel and abibrbing the water from their furface with a fpunge gently applied, or fufi^ering it to run off by draining, they fhould be put into a fufficient quantity of the menftruum to cover the preparation entirely. The next confideration is how to make ufe of the men- ftruum for corroding the parts to be diffolved and remov- ed from the veflels. For this purpofe the operator fhould be furniihed with a china bowl or a ftone veflTel, on which the menftruum can make no impreffion ; or what will an- fwer ftill better, a glafs vefl"el with a mouth fufficiently large to put in and take out the injected parts, without any difficulty. By CORROSION. 379 difEculty. It would be well to furniih it with a proper cover to reftrain the acid fumes from efcaping. I have always ufed a cover of cork lined with wax, into which, whilfi: it is in a melted ftate, the inferior fide of the cover may be dipped ; and this cover muft be cut fo as to fit ex- a£lly the mouth of the veflel. The great advantage of a glafs veflel over the others is its tranfparency, whereby we are able to fee how the corrofion goes on, and to judge when it is finifhed. This takes up from fix or feven days to a fortnight or three weeks, according to the nature of the part to be prepared, and to the quantity and concen- tricity of the menfliruum employed, in which it ought to be entirely covered. When the acid is very dilute, it proves rather antifeptic and a preferver of animal fubftances, than a corrofive menfl:ruum» Of difengaging the Corroded Subjiance. Fifthly. The laft part of the operation confifts in difen- gaging the loofened and corroded fubftance from that of the injeftion. In this piece of bufinefs we ought to take the greateft care, if we wifh to avoid breaking down the beautiful fmall veflTels of the part. With this view the acid fpirit employed as a menftruum fhould be decanted from the inje<£tion with great caution, whenever the corrofion of the furrounding fubftance is complete, fo that it no longer adheres to the veflels. In place of the corroding menftruum, Ibak the preparation in fimple water for three or four days. The loofe fubftance may be removed from the veflels, by pouring frefli water over the preparation flowly, and in fmall quantity at a time; or otherwife we may put the preparation in a velTel pierced with holes, like a cullender, and place this in fuch a manner as to receive a gentle current or ftream of water. If we ftiould place the veflTel near the nofel of a pump, and under the droppings or fmalleft ftream which we can procure to fall from it, the preparation may be thus cleanfed from the loofe corroded matter with which it is encompailed. But 380 ANATOMICAL PREPARATIONS But the method I have difcovered, and always pra£lifed as the fafeft and beft, is to make ufe of a fmall fyringe, the pifton whereof works eafily, with which, whilft the preparation is covered three or four inches over with wa- ter, I lyringe gently, fo as to wafh and clean it entirely from the corroded fubftance which is but loofely attached to it. In this manner, ufmg proper care, it may be per- formed perfectly without breaking down any, even the fineft parts, of the tender veffels. But if more force than needful is employed, even the droppings of a pump from a too great height, when the preparation is taken out of the water, will fometimes break down the extremities of the fmall veffels, and mar the beauty of it. After all thefe directions have been well executed, the preparation is to be fufpended for fome time in a fafe place, till it is dry ; then it is to be fixed on a wooden pedelfal, having a focket like a candleftick, in which it may be faft- cned with a little glue or melted wax. Then let it be co- vered with a tranlparent glais in form of a globe or bell, with the mouth downward, to guard it from accidents. This finifhes the work. Thefe preparations give us a moft exadl knowledge of all the ramifications and anaftomofes of the veffels, and often of the jun