6 ENGiN. LIB.: I ro i A 790,279 X,} j 2 Q.:.. r: 6 r ~ ~~ i. '. '.' " '. * C i s.' *.*,. * ' * " * * ' *: |s / ',, "...".' r * *: ' * *. * '''?" ' ' ' I '; ' '* ' ' ' '.., ".. * ** *. *. "* -...- j. ", * ':. *'' *. * * '''*: *.v: \ i;*' * ** x ^^^^ ^^^^^^ PROPERT Y 0? jI, r81 7 l ART ES SCIENTIA VERITAS UNITED STATES COAST AND GEODETIC SURVEY T. C. MENDENHALL SUPERINTENDENT GEODESY ON THE VARIATIONS OF LATITUDE AND ON DETERMINATIONS OF GRAVITY AND THE MAGNETIC ELEMENTS AT STATIONS IN THE HAWAIIAN ISLANDS A preliminary Report by E. D. PRESTON, Assistant APPENDIX No. 13-REPORT FOR 1891 0 WASHINTGTON GOVERNMENT PRINTING OFFICE 1 893 FA;I. Lflnw 2 1 -9 APPENDIX No. 13.-1891. ON OBSERVATIONS FOR THE VARIATIONS OF LATITUDE MADE NEAR HONOLULU, OAHU, HAWAIIAN ISLANDS, IN COOPERATION WITH THE WORK OF THE INTERNATIONAL GEODETIC ASSOCIATION, AND ON DETERMINATIONS OF GRAVITY AND THE MAGNETIC ELEMENTS. A preliminary report by E. D. PRESTON, Assistant. Submitted for publication January 17, 1893. This preliminary report will include notices ofI. The international latitude observations from June 6, 1891, to June 25, 1892. II. The measurements of the force of gravity on Oahu and Hawaii from June 9, 1891, to July 25, 1892. III. The determination of the magnetic elements made at intervals from August 11, 1891, to September 9, 1892. IV. Meteorological observations, including barometric determination of heights of Manna Kea, from July 1, 1892, to July 27, 1892. I. —OBSERVATIONS FOR THE VARIATIONS OF LATITUDE. The following are the circumstances that led to this work: Some latitude observations made in Germany, at Berlin and Potsdam, and at Prague in Bohemia, showed a progressive yearly change in the results. As the motion was in the same direction for all three places, it became desirable to make a further study of the movement by observing at stations differing greatly in longitude; for if there had been a real motion of the pole, the effect on terrestrial latitudes would be in opposite directions on different sides of the earth. In order, therefore, to bring out the law of change most advantageously the International Geodetic Association took the matter up and proposed to send an observer to the Hawaiian Islands to make latitude determinations simultaneously with those executed in Europe. The difference of longitude of Berlin and Honolulu is 1lh 25"M. The United States Government was asked to oSperate in order that the result of work, whatever it might be, should be checked independently by another observer and another instrument. i: his led to my assignment by the Superintendent of the Coast and Geodetic Survey, with instructions for some additional gravity, latitude, and magnetic observations during my stay in the islands. 479 U. 8. (COAST AND GEOI)ETIC SUIRVEY. I left Washinlto'fo( on() April 18, 1891, inll colipanty wit It Dr. Marcuse, the Eurtl)leant representative of the Illternatiional (Geoletic Associ;afioln, arrivilig at I lllnolulul on the 8th of May, in tle afttrnooll. Having been directed by the Superintendent to ol)serve the Transit of Mercury, which took place on tile 9tJh, provided we sllould arrive in time, the instrumellts we(le passed thltrougli the custoim-llouse on the day of landing; the sanie eveinling the station was selectedt at Waikiki 3 miles southeast of 1IJono111lu,:1and tlhe trantsit was successfilly observetd the followiiNg dty.* OuIr next occtlpation was to chBIose a pe})elrmaielt site for thel astront)omic'al work. Afteir sevelal wldisapl)pointlln(ts, the observattories were finally located oil the property of Mr. J. F. Brown, of the Governnment Survey, whlio generously gave the use of tihe ground during thie year. Waikiki was Irefierred in o(rder to avoid tle clouds of Honoluluf, as my exlperience there in 188:3 ld(l 1887 sliowed that 1place to be ver'y unfaivorable fotr contirnuous star o(bservations. There were itninerous unavoidable delays in getting' matlerial antd workincena, a (, das thle programnine was to begin work as soo011 after May 15 as possible, it was decided to concentrate all tle force o on oe build i ng and let one observer begin immiediately. As [ hlad seveial mo(re illstrutelll ts to set up titan my colleague, it was (deelned atldvis:able ti4i' himii to )begil first; so tltalt nily o(bservatory was inot finished aunitil five days after his. Be begait observatiotns on June 1; ily first ones were itade on Jlune 6. Fir(on this ldate on, tlie plai of work adopltctl was continluously (:arried out. LaItitudle observations were Iltadel in ( conne(tion)1 with I)r. Marccuse. Time was ((deterntined fi tilr ie ravit y wvorlk iii tlhe intervals btidlween pairsof stars, and( the petndullultt wats swung d(Il'ig tieetientie evening,l onlicidellc s bIeilig tiote(d ait, thle bgilllill g:alId e(nd of( thle iiglhts wo-rk, and whenever ()lpporltulity olti'e(!d (litringt tlae latittle altid timle obselrvation s. This gives a dettermin Iation of giavity correspoldiig to eacht latitude determinitationt, and will help to decide tlie tqueistion whletlier tlie cihage of latitude ctoil es l'roi l a rteal iuotion )of tile pole or froinll tratsfel'rs of large b)odlics of iatttc e tr ultder tile surtface of tlit(' (arth. From Jutle (,6 1891, to Junlle 25, 18)2, tlhere were tliade 2 13:4 dletelrinations of tlatitude; observations being made ot 220 nights, as lo)11ws: Nights..atituides. I Nilits. Latiluelcs. 891 )2 lune, 20 212 ialn ry, i S 195 July, 14 1 56 d ruary, 9 267 August, 20 254 Marc, S 215 September, i. 1r5 I10 122 October, II 1 24 2iv,2 219, November, 15 6) June, I 127 December, 9 2 I --- —--- 220 2434 * $ce a: report of thcse observatioins in Appendix No. 12, 1891. REPORT FOR 1891 —PART II. 481 II.-GRAVITY DETERMINATIONS. Before leaving for Honolulu I suggested to the Superintendent the feasibility of making continuous observations for the force of gravity. This was possible without increasing the expense of the work, alnd such observations were made at Waikiki every night that latitudles were observed. We thus have a series of nearly 200 nights of gravity determinations extending throughout the year. Time stars were observed before the first coincidence and after the last one, and -as many observations as possible were made on the pendllum at intervals between the latitude pairs, so that in all there are not far from 1 000 measures of the force of gravity. On June 15 the pendulunm apparatus was taken down at Waikiki allnd mounted at Honolulu. As I desired to continue the latitude work at the former place as long:as possible, the zenith telescope was left standing and the latitudes were continued on every clear night wlhile preparing the stations in HIon-olulu. After the pendulum observations were in operation the Waikiki work was still c:arried on whenever possible to observe stars. The lpenldulum was observed during the day at Honolulu and stars obtained during the early evenling. Then the trip was made to Waikiki (3 miles), and latitude continued until the end of the list. On June 28 we left for Hawaii, the party consisting of Prof. W. D. Alexander, the Surveyor-general, Mr. W. E. Wall. M1r. W. W. Chainberlain, Mr. Louis Koch, and myself. At \\Wainllea tire party was joined by Mr. J. M. Muir, a volunteer observer, who rendered valuable service on the mountain both in triangulation and nlagnetic work. The object of this trip was tthe determnilnation of the force of gravity at the base and summit of Mauna Kea, tle highest peak on the islands. The elevation is nearly 1.4000 feet. Other observeatiols were also made consisting of latitudea, Inagnetic, Ineteorologi cal, etc. Landing at Kawaihae on the evening of June 29, this station was occupied before July 7. Observations were made for latitude, time, gravity, and magnetism. From this point we passed to the plains of Waimea at an elevation of 2 600 feet. At this place aninals were engazged for the ascent and packers hired. While making the necessary arrangements, two stations were occupied for magnetic observations. One of these had been occupied in 1872 by the Government Survey officers and the other was a new station at the end of their base line. This work wals done at the request of the Surveyor-general. On July 12 the party left for Kalaieha. The ascent is very gradual. The trail winds around the mountain, and after a journey of 35 miles we found ourselves at an elevation of 6 700 feet above the sea. From this 1point to the summit the path is rough and steep. Only 12 mliles more tl\':-el were nec(essary to overcome the same vertical distance H. Ex. 43, pt. 2-31 482 IT. S. COAST AND GEODETIC SURVEY. that we had risen in traveling the 50 previous miles. A full series of observations was made at Kalaieha, but as this point lies just at the beginning of the cloudl region the greatest difficulty was experienced in getting stars. Only live pairs could be secured for latitude andl the tinme determillationsoi)r gravity are rather weak. Muchl l of the work was dlonell durilig raill. The 0l)bject) g'lass was lni(,cvered long ellough to make the observation while the star. was lpassinlg, and imlllle(liately after a pair was observed or after a half set for tilme the telescope was carried into the tent to be wiped alld diried. Owinlg to the great difficulty of trallsportingl baggage, no separate observatory tent was taken and the telescope was mountedo in the o}len air. At this point the )party was reinforced by tMr. E. D. Baldwin, of the G(overimnent Survey, whlo hliad come up on thle wilndwar1d side, bri1nging1 some pa(c'k nntules and a (guide from Hlilo. We be(ga' the ascent fro)n I ei ala-,ieha on July 19, withl a pack train of twenty-two animalls al id elevei meni. One of the doonkeys that carried the mnagitetic ilstrumelts ad(l some Lrewood )bec(lname unruly a1nd rati a way. As we were enveloped iln fog, lie found no difficulty il escaping, an11d was only re(apturedl at 3:30 p. 1l., after eight hours' huntillg by eigllht of the party. This necessarily d(eferred the trip one day, and aillther start wats 1madtel at 7:40 thle following morning. We arr'ive\( at Wailau, over 13000)) fteet elevation, late in the afternoon). Albout halft t:ll party Illn.e tlle ascent by 3 p. m., but as malny of thle a:li:IIals wer'e sltiring 'from the rarity of the air and f'ron the tra:vel overl tlie rougi lava;l, it was im-l),ossible to urge them much, and lany (lidi ntot arritve Ilntil late; inl fact, some did not get up at all, and from sheer' exlhastion refiuse(d to go leyond about 12 0)(0 fteet. They were ullloaled(l, a:111 tlheir loads ttake(i by stronger mules that had alreadly been to t tthe tol). d uIlloladed. A stay of five days and six iliglts wa s lliadle at, Waiau. Trhe ra1iges of temI)perature were from 13~ F. at night to 108~ at noolnday, the tllermomleter b:eiing il the same position for botl readings. 'The l)aclk animals arrived fron, below iat 11 a. in. of July 26. Everythitng was in readiness, land after' two malod one-half hours spenelt il packing the mules we started d(own. On the way we passed by Lilinoe, where in past times tle natives llad established a burial ground at al ele-,atiol olf about 12 50() feet, andl fallrther on we ca(me t)o hleal.l kakoi (tile:ax-1;makers' cave), wlhere befoiret the intro(luctioln of iron al qua'rry had been o)eleled fihr the prodiuction of battle-axes. The eleva tion of thlis point is over 1200}0 fleet. We arrived at Kalaieha the same eveninlg. Two (lays were p)assed here, reIpa'kilng tlle instruments and puttin the i1reords in order. All tlhe llggage was sent down the lee side of the island to Kawaihae, a distance of 50 miles, to be shipped to Itoolulu. As it was desired to make magnetic observations at Hilo, Mr. Baldwin, Mr. Wall, a11nd REPORT FOR 1891 —PART II. 483 myself left the party lhere. This could be done without increasing tlhe time spent on the islland, as we were able to take the same steamer that was to pass ronld the island and load the instl lruments at Kawaihae. II I.-MAG NETIC OBSEIVATI (ONS. The first of tllese were lmade onl August 11, 1891, whel enlgaged in the latitude observations at Waikiki. The date of occupation of this station was chosen so that all tle work could go on together. At the time meltioned our astronomical observ:ations extended from 7 p. In. to 11 p. m., With these lours tfor nighlt work it wlas possible to nmake magnetic observations for alll three elements during the day and allow no break to occur in the regular series for time, latitude, and gravity in the evening. The seconld station was mIadte at K'alllhuku, on the extreme no(rtth point of Oahu. Tlis made it nece ssary for me to be absent trom Waikiki from November 24 to Novenllber 2!. Leaving Waikiki at 6 a. m. of the 24th, the distance to WaVialmla was m(ade by 3 Ip. mii., wlere ltneh was taken. In the evening the renlain(ler of tle trip was made, and we arrived at Kahuku at S p. in., having rid(len horseback more thll 40 miles over a (lifficult road. On the tollowing morningl, Novenmber 25, observations were begun. Tlley wer'el compllleted on the 27th, and we were back in Honoluilu on the eveningl, of the 28th. Prof. Alexander.accompanied me and kindly recolrded these observations. Honolulu was occupiied on June 2,:1 andl 4 1892, at the same time that the Waikii work was in progress. The subsequent magnetic stations, up to the time of th'e colclllsion of the Manna, Kea work, were occu lied in connection with gravity and latitude observations, and have already been (lescribedl. We arrived at Hilo on the evening of July 28, having passedl thirteen c1onsecutive lhours in the saddlell. lThe trail tfroml Kalaieh is 35 miles long, and much more tlhaln al' of it is ov(er barie lava of thlle "laa" and "pahhoeoe" types. No tlraveler attempl)ts tllis trip without carrying horseshoeing implemlents, tfi thle lava is of such a; nature thlat the hoof of an unshod horse wotulld e,cut tllrough ill a few minutes, and nothing could induce tlie animal in that case to continue the journey. We saw the carcasses of a dozen hlorses that <had been mercifully killed or unmercifully left to (lie 1'f starvation. Cocoanut Island wals }occ:ulpied at Ililo from July 30) to Augulst 3, land we arrived in lloniolilll o)n August 6. At the reqluest of Prof. Alexander, tlhe Surveyyor-general of the Kingdom, 1 lei't on tlhe next steamer for Kealakeaku. Bay to re-occ(upy the magnetic station of Capt. Cook at Napoopoo. His ol:servations were made more thall oine hundlred years ago, a;t(l were finished just before thea olltbreak which cost thle great discoverer hlls life. On the W ay back to IHoItllulu J stopped three days at Lahaina, and made magnetic observations 484 U. S. COAST AND GEODETIC SURVEY. where De Freyeinet had an observatory in 1819. Honolulu was again reached onl August 27. Two more stati )ns remained to be occupied, and on August 30 we left for Kauai. The work being done at Waimea I went on board the Mikahala. Learning that before returning to Hionolulu slhe wouldl go to Niihau I determined to make the trip and get one station on that seldom visited island. This neither increased the expense nor delayed my return, as otherwise it would have been necessary to wait at WTairea until the vessel came back. IV.-METEOROLOGICAL OBSERVATIONS. When it was decided to occupy the summit of the highest mountain in Hawaii, the occasion was taken to verify its height, as determined previously by Prof. Alexander. To this end barometers were read at the four mountain stations, Kawaihae, Waimea, Kalaieha, and Wailau. Simultaneously with this, barometric observations were made ill IIonolulu, and at Hilo and Waimnea, on Htawaii. The wet and dry lblb thermometers were also read for the relative humidity, and the direction andf force of the wind, the percentage of clouds, etc., were imoted. On the sumnmit the mercurial barometer stood at approximately lS-3 inches at a temperature of about 54~ F. On Septenlber 14 1 took passage in the steamship Australia for San Francisco. Arriving on the 21st, I found orders from the Superintendent to measure the force of gravity at the Lick Observatory. This was done between September 28 and October 2, the time between September 22 and 27 being emnlployed in gettilg the instruments through the custom-house and in repairing the pendulum apparatus, which was considerably out of order from the experiences on the top of Mauna lKea. On October 4 1 startel for Washington and arrived on the 16th. Ill elosing, I desire to express my obligations to the Surveyor-general, I'rof. W. 1). Alexander. Throughout my entire stay I was the constant recil)ient of professional favors. The observatories at Waikiki, the meridian mark on Makiki, and the transportation of the heavy outfit to tlhe gravity station above the clolds, all bear testimony to his generlous iaid. It is diue to the Hawaiial Government Survey to state thatit thie greater part of the 311anall Kea expenses were borne by that lBir1eau. REPORT FOR 1891-PART II. 485 The following table gives a summary of the season's work: Summary of observations in the Hawaiian Islands in 1891-'92. Nights No. of Station. Island. Date of occupation. Class of obser - - Rerks. I1 _va tos ______ 1 ton tions. tions. tions..I. I e v a Waikiki. Kahuku. Honolulu. Oahu. Kawaihae. Hawaii. Waimea. Kalaieha. Waiau. HIilo. Napoopoo. Lahaina. Waimea. 1891. 1892. June 6-June 25 June 9-June II June 9-June II 1891. Aug. I I-Aug. 13 Nov. 25-Nov. 27 1892. June 23-June 25 June 15-June 27 June 2-June 4 July 4-July 6 July 3-July 6 July 3-July 6 July I-July 3 June 30-July 7 July 8 July 9-July II July 7-July ii July 14-July 15 July 14-July i6 July 14-July 18 July 14-July i6 July 13-July 18 July 2I-July 25 July 22-July 25 July 21-July 25 July 21-July 24 July 21-July 26 July 30-Aug. 3 Aug.Aug. 8-Aug. Aug. 23-Aug. 25 Sept. 2-Sept. 3 Sept. 5-Sept. 6 Sept. 9 Latitude. Gravity. Time. Magnetic. do. Gravity. Time. Magnetic. Latitude. Gravity. Time. Magnetic. Meteorology. Magnetic. dlo. Meteorology. Latitude. (ravity. Time. Magnetic. Meteorology. Latitude. Gravity. Time. Magnetic. Meteorology. Magnetic. (10do. do. do. do. (10. 3 3 10 3 3 4 4 I 5 2 3 6 3 6 4 4 4 3 6 5 4 3 2 2 I 220 2434 199 827 202 202 3 3 57 Io0 3 23 91 4 3 I 2 3 67 6 3 55 8i 4 3 3 2 2 I West base. (ld station. Latitude station, 1887, and transit of Venus, 1874. Thorny Croft. Maui. Kauai. Nonopapa. Niihau. In the column " Nuimber of leterminnatiolls," the figures indicate: or latitude. --- The number of pai-s of stars. Frgiravity.-The number of intervals, each giving one value for the period of oscillation of the pendulum. For time.-The number of sets of stars, each one giving a correction to the chronometer. For mzagnetic.-The number of determinations of all three elements ---declination of the needle, the dip and the horizontal intensity, and time and azimuth. The meteorological observations were made many times during the day. The barometer was read at the times of maximum and minimum, at 9 a. m. and 3 and 9 p. m. On the summit of Mauna Kea it was read more frequently. X-r Date Due __________ ____ __ I ___ _______ ____________ ____ _____ ________________A _______________ ______________________ _______________ _____________________ I ___________________ UNtIVERSY oF MICHIGAN 3 9015 00200 3120 BOUND JUN 17 1952 UNIV. OF 4HCH, UBRARY Engineering Library QB 296 ~U62 H3 P95 Preston, E.D. On the variations of latitude and on determinations of gravity and the magnetic elements at stations in the Hawaiian Islands 7777' EAR ME