Class. J__ REPORT BOUNDAEY COMMISSION SURVEY AND REMARKING OF THE BOUNDARY BETWEEN THE UNITED STATES AND MEXICO WEST OF THE RIO GRANDE, 1891 TO 189G. PARTS I AKD n. FART I. REPORT OF THE INTERNATIONAL COMMISSION. FART II. REPOR'T OE THE UNITED STATES SEdlON. WASHINGTON: GOVERNMENT PRINTING OFFICE 25425 ^^ 1899 X^/"irASH\*^ MESSAGE PRESIDENT OF THE UNITED STATES, TRANSMITTING A REPORT FROM THE SECRETARY OF STATE, ACCOMPANIED BY THE REPORT OF THE UNITED STATES BOUNDARY COMMISSION, PURSUANT TO THE CONVENTION BETWEEN THE UNITED STATES AND MEXICO OF JULY 29, 1882, TOUCHING THE RE-MARKING OF THE BOUNDARY LINE BETWEEN THOSE TWO COUNTRIES WEST OF THE RIO GRANDE. To the Congress of the Vnitid States: I transmit herewith a report from the Secretary of State, accompanied by the report of the United States Boundary Commission, pursuant to the convention between the United States and Mexico of July 29, 1882, touching the re-marliiug of the boundary line between those two countries west of the Rio Grande. I urge that provision be made for the immediate printing of a suflicient supply of this valuable document. William McKinley. Executive Mansion, Washington, April 26, 1897. Tile President: I transmit herewith the report of the United States Boundary Coin mission under the conven- tion between the United States and Mexico, concluded July 29, 1882, which provided for an international boundary survey to relocate the existing frontier line between the two countries west of the Rio Grande. Tiie commissioners on the part of the United States were Col. J. W. Barlow, Corps of Engineers, U. S. A.; Capt. D. D. Gaillard, Corps of Engineers, U. S. A., and Mr. A. T. Mosniaii, of the United States Coast and Geodetic Survey, Treasury Department. Tliey have discharged their work in a creditable and satisfactory manner, as will be further seen by the report and its several accompaniments. Inclosing as a part of the record in the case a copy of a letter from the commissioners, dated November 25, 189G, the subject is respectfully submitted for your consideration. Respectfully submitted. John Shekman. Department of State, Washington, April 22, 18'.>7. List of accompaniments. Report, 3 volumes. Maps, 1 voluiiie. EngraviDgs, 1 volume. Letter of November 25, 189(5, from the commissiouers to the Secretary of State, with its accompaniments. 4 united states and mexican boundaey. Department of State, International Boundary Commission, United States and Mexico, Washington, B. C, November 25, 1896. Sir: The coniiiiissioiiors on tlie jiart of tlie United States have the honor to submit herewith their final report on the survey and remarking of the boundary between the United States and Mexico west of the Rio (iraiide, pursuant to tlie convention between the United States and Mexico of July 29, 1.SS2, revived by the convention of February 18, 1889, and continued until October 11, 1896, by that of April 21, 1894. The report consists of the following: First. The report of the joint commission (in triplicate, one copy being in the Spanish language), dated August 14, 1896. An atlas, bound in leather, containing 19 sheets of the boundary map. One volume bound in leather, of 300 illustrations, showing views of the monuments and scenes adjacent to the boundary. Second. The report of the United States section of the commission, consisting of 2 volumes (in duplicate) arranged in 10 chapters, including appendixes. One atlas, bound in leather, containing 5 sheets of profile and 2 sheets, index map. Two atlases (three retained by tlie commissiouers), each containing 19 sheets of the boundary map, 5 sheets of profile, and 2 sheets, index map, showing the adjacent country. Two volumes of illustrations (seventeen retained by the commission for distribution to the libraries of the War Department, the .Military Academy at West I'oint, and the principal employees of the Survey. Sixteen volumes (four sets) of the ])hotographs and about GOO negatives were jireviously sent to the Department. Inclosed herewith is a list of cojiperplates, electrotypes, original maps, survey records, etc., which are transmitted in connection with the report. In presenting this report of the work upon which the commission has been engaged during the past four years we beg leave to express our ai>preciatiou of the uniform support aud kind consideration received at all times from the Department, without which our labors would have been much more difiBcult. We would also put on record the fact that throughout the many trying and often delicate conditions of an international character, which have of necessity arisen during the progress of the work, our associates of the Mexican commission have invariably shown a spirit of fairness and courtesy which has always rendered possible the satisfactory solution of every jierplexiug question. To SeHor Jacobo Hlanco, engineer in chief of the Mexican section, who is a thorough Knglish scholar, special thanks are due for valuable assistance in translating ;.nd interpreting, rendering the employment of a special translator unnecei*sary. This report may now be laid before the President with a view to tlie tiansmissiou thereof to Congress. With highest respect, your obedient servants, J. W. Barlow, Colonel of Entiineers, U. S. A., D. D. Gaillard, Captain of Enaimrrs, U. S. A., A. T. MoSMAN, Assistant, Coaxf and Geodetic Survey, Commissioners. The Skoretarv of State, Wasliinyton, l>. C. UNITED STATES AND MEXICAN BOUNDARY. 5 List of hoxix mill rolls {with i numeration of mntents) transmiUml to thi- Deparlnunl of Stale iiilli thf nport of tin: International Bonnilarji Commission, Unitid States and Mexico, icest of the l!io t:rinidr. Six boxes loutaining 300 half-tone coppeiphitea of illustrations to accompany joint ri'poi t. One rack for copperplate holders. Twelve boxes (copperplate holders) containing copperplates of map sheets Nos. 1, 3, 5, 7, 9, 11, 13, 15, 17, 19,25, and 26, each box being marked ''Mexican bonndary «est of the Rio Grande," with its plate number. Ten boxes (electrot.ype-plate holders) containing electrotype plates of map sheets Nos. 2, 4, 6, 8, 10, 12, 14, IK, 18, and 19a, each box being marked " Mexican boundary west of the Rio Grande," with its plate number. One roll containing 220 photolithographs, 44 sets, of the profile sheets, 90 illustrations for report of United States section, Chapter IV, and 5 atlas title sheets. One roll containing 17 original maps, being sheets Nos. 1, 2, r<, (i, 7, 9, 1 1, 14, is, 19, 20, 21, 22, 23, 24, 25, nu-l(i Section 6: Plan of operations agreed upon by the engineers-in-chief of the two .lectious for snrveyinj; and raarkiiif; the bonndary 17 Agreement in regard to size and sliape of the monuments and the method of erection 18-19 Section 7: Journal of the proceedings of the joint commission to October 1, 1891 20-23 Section 8: Astronomical detenninations — Longitude 23 Latitude 21 Azimuth 24 Longitude results by United States section 25 United State.s latitude observations and table of results 25 United States azimuth observations and table of results 2G Mexican observations for longitude and table of results 27 Mexican observations for latitude and tal>Io of results 27 Mexican observations for azimuth and table of results 27-28 Final results for latitude, by both sections 28 Section 9 : Geodesy — Tables of United States and Mexican tangents, parallel of 31^ 47' 29-30 Tables of United States and Mexican distances, meridian section 30 Tables of United States and Mexican tangents, parallel of 31° 20' 30-31 Tables of United States and Mexican distances, Sonera azimuth line 32 Tables of United States and Mexican distances, California azimuth line 32 Operations of the Mexican section 32 Operations of United States section 33 Joint operations 33 United States triangulation n<^ar Monument No. 1 33 Mexican determination of longitude of Monument No. 1, by flashes 33 Triangulation at Nogales 33 Triangulation near Yuma 33 Limits of diiference of United States and Mexican results for distance and offsets 34 Table of final distances on parallel 31^ 47' 34-35 Table of final distances on meridian section 35 Tal)lo of final distances on parallel 31'^ 20' 36-37 Table of final distances on Sonera azimuth line 37-38 Table of final distances on California azimuth line 38-39 10 UNITRD STATES AND MEXICAN HOUNDAKY. Sfx'Tion 10: .Mt'tlioda used in the original siirvny lS49-lXo()— Page. Astronomic:!] iletfrrainsitions of tlie original snrvcy 39-40 Method of ninninff the lino on tho ground 40 Comparison of distances determined hy the original snrvey, 1849-1856, with those obtained hy the present commission 41-16 Distances on parallel Sl"^ 47' 41 Distances on meridian section 41 Distances on parallel 31" 20' 43 Distaiices on Sonora line 44 Distances on California line 4(5 Measnres of the 20 miles from junction of the Gila and Colorado to the initial point in the Colorado . . 45 Differences V)etwoen the determinations of longitude by the original commission and those of the pres- ent survey 46-47 Original ninminients 47-49 Section 11 : Topography- Topography of United States section 49-50 Tojiograjjhy of Mexican section 50 Section 12: Journal of joint commission from October 11, 1895, to February 24, 1896 51-52 Section 13: Construction of maps of the boundary 53 Table of mean latitudes of astronomical stations 53 Table of mean latitudes and longitudes of monuments on parallel 31' 47' 54 Table of mean latitudes and longitudes of monuments on parallel 31 " 20 ' 54 Table of mean latitudes, longitudes, and azimuths, and distances on Sonora line 55 Table of mean Latitudes, longitudes, and azimuths, and distances on California line 55 Journal of proceedings at final meeting of the International Commission, August 14, 1896 55-56 LIST OF ILLUSTRATIONS. PAET I. Page. 1. View on wagon road cast of Nogales Froutispiece of Volume. 2. Custom House, El Paso 12 3. Type of New Iron Monument 18 4. Camp No. 1, Rio Gnmde 20 5. Observatory at Monument No. 204, Arizona 28 6. Mexican Consulate, Nogales 32 7. View in Yuma, Ariz .S:t 8. Old Mission, San ,Io86 de Tnmaeacori 44 9. Old Mission, San Xavier del Bao 51 REPORT OF THE JOINT COMMISSION. SKCTIOX 1. The bouiulary between the Republies of the ITnited States .iiid Mexico was defined by the treaty of Guadahipe Hidalgo, and subsc(iuent)y modified by that luiown as the Gadsden treaty, or treaty of La Mesilla. The first of these was conchided and signed at the city of (inadalupe Hidalgo, on the 2d of February, 1848, by the dnly authorized i)lenii)otentiaries of the resi)ective Governments. Tiiese were, on the part of the United States, Mr. Nicholas V. Trist, and on the ]>art of Mexico, Senores Bernardo Oouto, Miguel Atristain, and Luis G. Guevas. Following is a copy of Article V of the treaty of Guadalup*^ Hidalgo, which relates specially to I he boundary between the two countries : AuTiCLK V. The bouiulary line between tlio two Rcpnblics shall commence in the Gulf of irexicn, throe leagues from land, opposite the mouth of tlie Kio Grande, otherwise called Rio Hr.avo del Norte, or opposite the mouth of its deepest branch, if it should have more than one branch emptying directly into the sea; from thence np the midart formed by the Rio Grande and the Rio Colorado, was duly established. The direction of the California boundary was not changed, but its eastern terminus was fixed at the jioiiit where it crossed the channel of the Rio Colorado, about G miles (10 kilometers) west of the Gila. The inoniinient previously erected near the junction now being unnecessary, was utilized to mark a point on the new Arizona and Sonora line near its western terminus. In addition to the G monuments, which remained to mark the California boundary, the com- missioners reported that 47 had been placed along the line from the Rio Grande to the Colorado. These were all shown ujion the Mexican copy of the joint map, while upon the American copy but 46 were represented. Of these 53 boundary marks, alleged to have been placed along the entire line west of the Rio Grande, the majority were but rude piles of stone; a few only being of a durable character, and provided with proper inscriptions, while the intervals between them were found to be in some cases as great as 20 or 30 miles (32 or 48 kilometers), and in one instance 101 miles (1G3 kilometers). The durable monuments were, notably, Nos. 1, 2, and 3 on parallel 31° 47', and those marking the extremities of the meridian section, the latter and No. 1 being of dressed stone laid in mortal". A full account of the methods used in establishing the old uiouunients, and their character, will be found in section 10 of this report. U. S. CusToM-HorsK, 1-; UNITED STATES AND MEXICAN BOUNDARY. 13 SECTIOIir 3. In later years settlers entered upon the lands adjacent to tlie boundary, and mines were discovered in its immediate vicinity. Difficulties tlien arose regarding the exact location of tbe line, it being charged that some of the original marks had been destroyed or removed. To put ail end to these difficulties a convention between the two Governments was concluded at the city of Washiugtou, July 29, 1882. Following is a copy of this convention: The President of the United States of America on the one hand, and the President of the United States of Mexico on the other, being desirous of putting an end to whatever difficulties arise from the destruction or disidaccment of some of the monuments erected for the purpose of marking the boundary between the two countries, Lave thought proper to conclude a convention with the object of deKuing the manncu' in which the said monuments are to be restored to their proper places and new ones erected, if necessary ; to which end they have appointed as their pleni- potentiaries, to wit: The President of the United States of America, Frederick T. Frelinghuyseu, esquire, Secretary of State of the United States of America; and the President of the United States of Mexico, Se.lor Don Mati.as Komero, envoy extraordinary and minister plenipotentiary of the United States of Mexico, iu Washington; Who, after reciprocal exhibition of their full powers, found in good and due form, have agreed upon the following articles : Article I. With the object of ascertaining the present condition of the monuments marking the boundary lino between the United States of America and the United States of Mexico, established by the treaties of February 2, 1818, and December 30, 1853, and for determining generally what monuments, if any, have been destroyed or removed and may require to be rebuilt or replaced, a preliminary reconnoissance of the frontier line shall be made by each Government, within six months from the exchange of ratifications of this convention. These reconnois- sancos shall be made by parties >mder the control of officers of the regular army of the respective countries, and shall be effected iu concert, iu sach manner as shall be agreed upon by the commanders of the respective parties. The expense of each reconnoifcring party shall bo borne by the government in whose behalf it operates. These reconnoissance parties shall report to their respective Governments, within eight months from the exchange of the ratifications of this convention — (a) The condition of the present boundary monuments. (h) The number of destroyed or displaced monuments. (c) The places settled or capable of eventual settlement, where it may be advisable to set the monuments closer together along the lino th.an at present. (rf) The character of the now raonuuients re(iuired, whether of stone oi iron, and their number, approximately, in each case. Akticlk II. Pending the conclusion of the preliminary reconnoiss.ances provided iu Article I, each Government shall appoint a surveying party, consisting of an engineer in chief, two iissociates, cue of whom shall be a priictical astronomer, aud such number of assistant engineers and associates .as it may deem projier. The two p.arties so appointed shall meet at El Paso del Xorte, or at any other convenient place to be .agreed upon, within six months from the exchange of the ratifications hereof, and shall form, when combined, an "International Boundary Commission." Article III. The International Boundary Commission shall be required and have the power and authority to set iu their proper places along the boundary line between the United States and Mexico, from the Pacific Ocean to the Rio Grande, the monuments heretofore placed there under existing treaties, whenever such monuments shall have become displiiced; to erect new monuments on the site of former monuments when these shall have been destroyed, .and to set new monuments at such points as nuiy be necessary and lie chosen by joint .accord between the two couuuissioner engineers iu chief. In rebuilding anil replacing the old monuments and in providing for new ones the respective reports of the reconnoissance parties, provided by Article I, maybe consulted: Proiided, howerer. That the distance between two consecutive monuments shall never exceed 8,000 meters, and that this limit may be reduced on those parts of the line which are inhabited or capable of habitation. Aktkle IV. Where stone shall be found in sufficient abundance the monuments may be of stone, and in other localities shall be of iron, iu the form of a simple tapering four sided shaft with pediment, rising above the ground to a height of 6 feet, aud bearing suitable inscriptions on its sides. These monuments sball be at least two centimeters in thickness and weigh not less than 500 pounds each. The approximate number thereof to be required may be determined from the reports of the preliminary reconnoissance parties, aud the monuments, properly cast and finished, may Ije sent forward from time to time to such spots as the commission may select, to be set in place at the sites determined upon as the work progresses. Article V. The engineers iu chief of both sections shall determine, by common consent, whiit scientific processes are to be adopted for the resetting of the old monuments and the erection of the new ones, and they shall be responsible for the performance of the work. (")n commencing operations, each section shall report to its Government the plan of operations upon which they shall have jointly agreed ; and they shall fiom time to time submit reports of the jirogrcss m.ade by them in the said operations; .and finiilly they shall present a full report, accompanied by the necessary drawings, signed by the engineer in chief and the two associate eugim'ers on each side as the official record of the International Boundary Commission. Article VI. The expenses of e.ach section shall be defrayed by the Government which apiiointed it; but the cost of the monuments and of their transportation shall be equally shared by both (iovcrnments. 14 UNITED STATES AND MEXICAN BOUNDARY. Akticlk VII. Whenever the number of thu inoiuniiuiits to be set up Hliall be approximately known as the result of tlie labors of tbe preliminary recouuolssance parti.s, the engineers in chief shall prep.arc an estinuite of their cost, couveyance, and setting up; .and when such estimate shall have been approved by both Governments, the mode of making the payment of the part to be p.iid by Mexico shall be determined by a special arrangement between the two Gov<'rnmeiit8. AnTiCLE VIII. The work of the International Boundary Commission shall be pushed forward with all expedition ; and the two Governments hereby agree to regard the present convention as continuing in force until the conclusion of said work, provided that such time does not exceed four years and four months from the date of the exchange of the ratifications hereof. Article IX. The destruction or displacement of any of the monuments described herein, after the line shall have been located by the International Boundary Commission as aforesaid, is hereby declared to bo a misdemeanor, ])uni8hable according to the justice of the country of the offender's nationality, if he bo a citizen of either the United States or Mexico; and if the offender be of other nationality, then the misdemeanor shall be punishable according to the justice of either country where he may be apprehended. This convention shall be ratified on both sides and the rectifications exchanged at Washington as soon .as possible. In testimony whereof we have signed this convention in duplicate, in the English and .Spanish languages, and affixed hereunto the seals of our arms. Done iu the city of Washington this 2yth day of July, in the year of our Lord one thousand eight hundred and eighty-two. Freu'k T. Fhelinghuvsen. [seal.] M. Romero. [seal.] Tliu reconnoissauce provided for by this couveution was made iii 1883 iudepeiidoiitly by officers of the American and Mexican Goveriimeiits re.spectively, and reports were duly submitted which veriaed the necessity of a more detiuitc deniarkatiou of the boundary. SECTION 4. The convention of 1882 in its further provisions was not carried into effect before the date of its expiration, and another conveutioii to revive and continue the same was concluded February IS, 1889, between the two Governments. Following is a copy of this convention: Convention between the United States of America and the United States of Mexico, to revive the provisions of the convention of July 29, 1882, to survey and relocate the existing boundary line between the two countries west of the Rio Grande, .and to extend the time fixed iu Article VIII of the said convention for the completion of the work in iinestion. Whereas the provisions of the convention between the United States of America and the United States of Mexico, signed at Washington on the twenty-ninth of July, one thousand eight hundred and eighty-two, to survey and relocate the existing boundary between the two (^ouutries west of the Rio Grande, so far as they relate to Article VIII of said ccmveution, have not been carried out through delays iu the appointment of the comiui.ssiou to undertake the work; And whereas, by the additional article to tlie said convention, signed at Washington the fifth of December, one thousand eight hundred and eighty-five, the tini.^ fixed iu Article VIII of the said convention of .July 29, 1882, was extended for a period of eighteen months from thr, expiration of the term stipulated in said Article VIII. And whereas, the said additional pi'riod of time, as so extended, h.as expired Avithout tlie appointment of the .commission in (|nestiou, and the said convention has accordingly ceased to be in force pursuant to the iirovisious of Article VIII thereof; And whereas, it is the wish and understanding of the United States and Mexico tliat the provisions of the said convention of .luly 29, 1882, shall be revived and continued in force and ott'ect until the completion of the work for which it was originally negotiated, they have appointed for this purpose, their respective plenipotentiaries to wit: The President of the United State's of America, Thomas F. Bayard, Secretary of State of the United States of America, and The I'rcsiilent of the United States of Mexico, Matias Romero, invoy extraordinary ami minister jilenipotontiary of the United States of Mexico in Washington, Who, after having communicated to each other their respective full powers, found iu good .and due form, have agreed ui)on and concluded the following articles: Article I. In view of the fact that the origin.al convention of July 29, 1882, between the United States and Mexico, providing for tl o resurvey of their boundary line, has lapsed by reason of the failure of the two Govern- ments to provide for its further extension before the 3d day of .January, 1889, as contemplated by the additional article to that convention, of December .5, 1885, it is hereby mutually agreed and expressly understood by and between the contracting parties hereto that the said convention of July 29, 1882, and every article and clause thereof, ;ire hereby revived and renewed as they stood prior to January 3, 1889. Article II. The time fixed in Article VIII of the convention concluded .at Washington July 29, 1882, between the United States of America and the United States of Mexico, to establish an intern.ational boundary commission, for the purpose of resurveying and relocating the existing boundary line between the two countries west of the Rio Grande, as provided for in said convention, and which was extended for eighteen mouths from the expiration of the term fixed in Article Vlll of the said convention of July 29, 1882, is hereby further extended for a period of five years from the date of the excliaugi' of ratifications hereof. UNITED STATES AND MEXICAN BOUNDARY. 15 This couveutiou shall be ratified by the contracting parties in conformity with their respective constitutions and its ratifications shall be exchanged at Washington as soon as possible. In faith whereof we, the undersigned, in virtue of our respective full powers, have signed the present conven- tion in duplicate, and have thereunto affixed our respective seals. Done at the city of Washington the 18th day of February, in the year of our Lord one thousand eight hundred and eighty-nine. T. F. Bayard, [seal.] M. Romero, [seal.] SECTION 5. Pur,suaiit to the above convention, and to carry its provisions into eiiect, officers on the part of the two Governments were selected as specified in the following letters of appointment: Dkpartment ok Statk, Washington, November 13, 1891. J. W. Barlow, LiciUcnant-Colonet, Corps of Engineers, U. S. Army. David DuB. Gaillard, Lieutenant, Corps of Engineers, U.S. Army. A. T. MosMAN, Esq., of the XT. K Coast and Geodetic Survey. El Paso, Texas. Gentle.men: By designation of the President, you are to constitute the International Boundary Conimissinn on the part of the United States, as i)rovided by the treaty with Mexico of July 29, 1882, revived by that of February 18, 1889, to relocate, lu conjunction with a similar commission appointed by the Government of Mexico, the monu- ments marking the boundary lino between the two countries. The Department has no instructions to give for the execution of your work beyond referring you to the provi- sions of the treaty upon the subject and enjoining upon you the desirability and the necessity of prosecuting your labors to completion as rapidly as circumstances will permit. By the President's direction, Lieutenant-Colonel J. W. Barlow has been designated as special disbursing officer, and the Department's letter to him of the 6th instant, in so far as it relates to the expenditures on behalf of the Mexican Boniulary Survey, is made a part of these general instructious. I am, gentlemen, your obedient servant, .Iames 0. Blaine. * Department ok Fomento, Columzation, Industry, and Commerce, Mexico, Section 1st, No. 1930. In consideration of the capacity, patriotism, and other qualifications possessed by you, the President of the Republic has been pleased to appoint you ongineer-iii-chief of the commission, which, according to the respective treaties, will ])roceed to reestablish the monuments along the dividing line between Mexict> and the United States of North America. And I communicate this for your satisfaction and give you a term of two months for the presentation of vour credentials. Liberty and constitution. Mexico, October 14, 1S91. To Engineer .Iacohii Blanco. /'; M. Fernandez, O. M. 'Department of Fomento, Colonization, Industry, and Commerce, Mexico, Section 1st. In consideration of the .lualifications possessed by you, the President of the Republic has been pleased to appoint you adjunct aBtronomer of the commission to reestablish the monuments along the dividing line between Mexico and the United States of North America. And I communicate this for your information and give you a term of two months for the presentation of your credentials. Liberty and constitution. Mexico, October 19, 1S91. M. Fernandez, O. M. To Engineer Felipe Valle, Present. 'Depaistment ok Formento, Colonization, Indistrv, and Commerce, Mexico, Section 1st. In consideration of the qualifications possessed by you, the President of the Republic has been pleased to appoint you adjunct astronomer of the connnission to reestablish the monuments along the dividing line between Mexico and the United States of North America. And I communicate this for your information and give you a term of two months for the presentation of your credentials. Liberty and constitution. Mexico, October 19, 1891. M. Fernadez, O. M. To Engineer . I OSE Tamborrel, Present. * Translations furnished by Senor Jacobo Blanco, Mexican Commission. 16 UNITED STATES AND MEXICAN BOUNDAKY. SePiores Valle aud Tamborrel subsequently withdrew, their places beiug flnally lilled by the appointment of Senores Valentin Gama and Guillenno B. y Puga, with similar commissions. The instructions received from the Department of Fomento by the engineer in chief of the Mexican section, under date of November 3, 1891, were as follows: 'To fulfill the leiiulromeiits of the commissions conferred upon you and tlie other enginours who have bcLii placed under your orders to reestablish the monuments ou the boundary line between Mexico aud the United States of North America, you will observe the following instructions: 1. On your arrival at Paso del Norte you will, as soon as possible, put yourself iu communication with the engineer-in-chief of the boundary commission of the United States, in order to form the International Boundary Commission, according to Article II of tlie treaty of July 29, 1882, installing it with the formalities that will be agreed upon, and having the corresponding act signed by the chiefs of both commissions, as well as by the adjunct astronomers. 2. You will observe exactly the clauses of that treaty in everything that relates to the fullillment of the 3. According to Article V of said treaty, yon will determine by common agreement with the engineer in chief of the commission of the United States the scientific methods that must be adopte.l for the resetting of the old monuments and the erection of new ones, and you will report immediately to the Government the plan of oiieratious upon which you shall have agreed. 4. You will also arrange with the engineer in chief of the United States commission the epochs at which the reports referred to iu Article V of the treaty shall be reuilered. 5. As soon as the plan of operations is settled yon will proceed with the work with all possible activity, giving for that object precise and written instructions to each one of the engineers that form your commission. 6. All the data will be precisely recorded in field note books which will be delivered by each engineer to you as soon as they are filled up or the work is finished, with a duplicate copy, botli signed by tho^amo engineer. 7. In the instructions that you will give to every engineer, the form will be prescribi'd in which they will deliver their final results, not only for the general report referred to in Article V, but also with the object of proceeding without any delay to the publication of that report. 8. You will have corrected in the actual maps any error that may be found in the topograi)hlcal coiifigurati(m of the ground, .and the new settlements that now exist upon the line or its vicinity will be accurately delineated. 'J. Besides the reports referred to in the fourth of these iustruotious, you will communicate to the Government any matter that may occur in the course of oi)erations of sufficient importance to require consultation. Ill compliance with their instructions, the of3Bcers above api)oiiited assembled at I'aso del Norte on the 17tli of November, 1801, when a joint meeting was held iu tlie custom house of that city, on which occasion the Interuatioiiiil Boundary Commission was duly organized as retjuired by the convention. Tlie following declaration was drawn u]), copies of which, in English and Spanish, were transmitted to the proper authorities at Washington aud the City of Mexico: In the piiucipal hall of tlie custom-house of Ciudail Juarez 1,1'aso del Norte) of the Mexican Republic the undersigned, engineers in chief and associates of the two sections named for the reestablishmeut of the bonnd.ary line between Mexico Jiud the Uuit(^d States of North America, met on the 17th day of November, lyjl, in virtue of the treaty concluded in Washington on the 2tlth day of .July, 1882 (and renewed on the 18th day of February, 1889), and declared that from the date of meeting the "International Boundary Commission" was organized, for the jiurposes of the aforesaid convention, as expressed in Article II of the same. In testimony of which we have signed the present document in both the Spanish and English languages, iu duplicate. J. W. IUhi.ow, Lieut. Col., Corps of Evijineim. Jacouo Blanco, luijo. in ./<•/« de la Com. Mex., Uiihrivu. A. T. MOSMAN, AsstKlaiit, I'. S. Coast and Cvodctic SuriHiy. Kelii'e Vallk, Aslo. Adjo. de la Com. Mex. JOSIO TAiMliOURKI., Jdjunto Aalronomo C. M. de L. D. D. Gaillabi), First Lieut., Corps of Engineers. ' Translations furnished by Seilor Jacobo Blanco, Mexican Commission. UNITED STATES AND MEXICAN BOUNDARY. 17 (SKCTIOX Govevnnients to relocate the old monuments and erect new ones .along the frontier line west of the Rio Grande, pursuant to Article V of the treaty of July 29, 1882, revived by that of February 18, 1889. I. All monuments whose position, after verification, are found to be as located by the International Boundary Conmiission of 1849-1856 shall be accepted as positive bouudary marks. They may, however, be repaired or rebuilt II. Special astronomical determinations for latitude and longitude at the Ibllowing points will bo made: («) The Initial monument near El Paso; (6) The intersection of the one hundred and eleventh meridian with the parallel of 31'' 2p' near Nogales; (c) The terminal points, near San Diego and Yuma, respectively, of the azimuth line from the Pacific Ocean to the Colorado River. III. The position of the bouudary along the parallels of 31" 20' aud SI'' 47' will bo verified by astronomical or geodetic determinations for latitude at certain points, which, with those established as above described, will fix the direction of these lines. The distances between such definite points may be about 20 miles. The points of intersection of these parallels with the meridian section of the boundary may be verified, if deemed necessary, by astronomical determinations with the aid of the telegraph, if practicable. IV. The moiniments whose positions have been verifieil as above stated, and the new astronomical stations located as expressed in paragrapli three, shall form the general line of the bonnn the west side of each monument may be attached two socket rings for holding a flagstaff, for the purpose of more easily verifying the line between monuments remote from each other; these rings will be placed, one at the top of shaft, the other 12 inches below, and will be carefully located iu the plane of the boundary ; The engineers in chief further agreed that the inscriptions to be placed on the new monuments should be as follows: Ou north side : " Boundary of the United States, treaty of 1853, reestablished by treaties of 1882-1889." On south side: " Limite dc la Republica Mexicaua, tratado de 1853, restablecido por tratados de 1882-1889." It is at the present time impossible to prepare au accurate estimate of the cost of the monuments, including their conveyance and setting up, as required by Article VII of the treaty of 1882. An approximate estimate, however, can be given, based upon known difficulties attending the transportation of men and material in a desert country. The weight of the monuments as designed is 710 pounds, which is 200 j)ounds greater than the weight suggested in the treaty. If made to weigh 500 pounds, with be desirable, after a few trials, and was discontinued. Fourth. The weight of the castings exceeded the estimate, reaching an average of 800 pounds per monument. Fifth. The letters "NO," in connection with the figures ou the monuments, were considered unnecessary and were omitted. Sixth. Beneath the inscriptions on the north and south sides, respectively, of each monument, was added the following penalty notice in English and Spanish: "The destruction or displacement of this monument is a misde- meanor, punishable by the United States or Mexico ; " " La destruccion o dislocacion de estc monumeuto es un delito puulble por Mexico o los Estados Unidos." Seventh. After a number of sectional monuments had been put up, the design was changed to meet the difficul- ties of pack transportation. The new design provided 7 pieces— a base, a cap, and 5 intermediate sections, the latter each 14 inches high, resting one above another, and all held in place by a vertical bolt connecting the base and top section, the cap being fastened with rivets. The sectional monuments, when erected, were of the same appearanc^e as those cast solid. Agreement between the engineers in chief with respect to the destruction of Monument No. 255 and the adoption of a new site : San Diego, Cal., April 1, 1S95. Monument No. 255, built of granite, near Tijuana, having been destroyed by the fiood of .January, 1895, the two engineers in chief made a careful examination of the locality, but were unable to discover any parts of the lost monument. It had evidently been buried many feet below the bed of the river, which had so changed its course as to flow over the original site. It being deemed inexpedient to attempt to erect another monument ou the old site, it was agreed to abandon that location and adopt a new position for this monument on permanent ground. Accord- ingly, a survey was made in March, 1895, under the personal supervision and through the cooperation of the engineers in chief, and a site selected 1,080.()2 meters to the eastward of the old location upon which to erect a duplicate of the lost monument. .1. W. Barlow, Lieut. Cot. Eiuira., V. S. A., Engineer in Cliief American Section. Jacobo Blanco, Im/o. en Jefe de la Com, Mex. A granite monument, a duplicate of the one destroyed, including a protecting fence, was erected at the point determined, and the map and records changed to conform to the new location. 20 UNITED STATES AND MEXICAN BOUNDARY. SECTION 7. JOURNAL OF PROCEEDINGS OF JOINT COMMISSION. El Paso, Tex., August 19, 1893. The joint commission met at 9.30 a. m. Present, Seuor Jacobo iJlaiico, Col. J. W. Barlow, Sefior Felipe Valle, and Lieut. D. 1). Gaillard. (Mr. Mosmau absent in camp at San Bernardino.) The measured distances along parallel 31° 47' and the meridian section of the bonndaiy were compared and found to agree closely. The tangents and meridian, as traced by each section, and the offsets to existing monuments were then compared and found to agree well. It was agreed to accept all existing monuments on this portion of the boundary, and to locate all new monuments on the geodetic arcs joining existing monuments for the particular part of the boundary considered in the meeting to-day. (Parallel 31° 47' and the meridiau section.) Jacobo Blanco, Emjineer in Chkf Mexican Section. J. W. Barlow, Engineer in Chief American Section. Felipe Valle, Adjnnto Astronomo dc la Seccidn Mexicana. D. D. Gaillard, First Lieut, of Engineers, U. S. A. Yuma, Ariz., 3Iay 15, 1893. The joint commission met at 10 a. m. Present, SeFior Jacobo Blanco, Col. J. W. Barlow, Mr. A. T. Mosman, SeFior Valentin Gama, and Lient. D. D. Gaillard. (Seuor Felipe Valle absent in the City of Mexico.) The measured distances along parallel 31° 20' were compared and found to agree well with each other and with the astronomical determination of the total distance. It was agreed to accept all existing monuments on this parallel except the one on the west side of the Pedregosa Mountains, which is to be further inspected by Col. J. W. Barlow and Seuor Jacobo Blanco, and by them accepted or rejected. It was agreed to hicate all new monuments for parallel 31° 20' on the geodetic arcs joining existing accepted monuments. Jacobo Blanco, Ingo. Jefe fie la Com. Mex. J. W. Barlow, Lieut. Col., Corps of Engineers. A. T. Mosman, Assistant, U. S. Coast and Geodetic Survey. Valentin Gama, Asto. Adjo. de la Com. Mcx. D. D. Gaillard, First Lieut., Corps of Engineers. Camp on Parallel 31° 20' West of the Pedregosa Mountains, Jul}/ 3ii, 1893. Pursuant to an agreement made by the joint commission of the United States and Mexican boundary at Yuma, Ariz., on the loth day of May last, the engineers in chief of the two sections of the commission, viz, Seilor Jacobo Blanco and Lieut. Col. J. W. Barlow, have on this day carefully inspected the monument at the point mentioned, and decided to accept it as one of the original monuments of the boundary. Jacobo Blanco, Ingo. en Jefe de la Seccion Mexicana. J. W. Barlow, Engineer i7i Chief of the American Section, UNITED STATES AND MEXICAN BOUNDARY. 21 San Diego, Cal., December 28, ISDi. It is hereby agreed between the engineers in chief of the United States and Mexican Boundary Comraission that the monument referred to in agreement dated May 15, 1893, and its supplement of July 2C, 1893, is understood to be the monument near the Gallardo Mountain which was found and located by the American surveying party. Jacobo Blanco, Iiigo. en Jefe Seecioii Mexicana. J. W. Barlow, Lieut. Col. Engrs., U, S. A., Engineer in Chief American Section. In the village of Nogales, State of Sonera, on the 15th day of November, 1893, there were present Mr. B. A. Wood, of the American section, and Capt. Gaspar Martinez Oeballos, of the Mexican section, of the International Boundary Commission, who compared, in the presence of Senor Jacobo Blanco, engineer in chief of the Mexican section, the data and results obtained, by both sections, along the azimuth line, from the ertremity of parallel 31° 20' to the Colorado Kiver, as far as Monument IX. The comparison of said data and results showed clearly that the monuments as far as No. IX were well identified, with the exception of No. XIX. No. XI was not found. It was agreed, consequently, to accept the monuments from the extremity of the parallel to No. IX, inclusive, with aforesaid exceptions, and interpolate between them the new monuments in a straight line, admitting, in case of discrepancy, a difference not exceeding 2 meters, which will be equally divided, it being understood, however, that should the ditterence be considerable, though within the limit, the line shall be checked and the discrepancy be reduced as much as possible. B. A. Wood, Assistant Engineer, American Section. Caspar Martinez Ceballos, Ca2h 2, Ingo. Ayudte. de la Seccion Me.r. ' Jacobo Blanco, Ingo. en Jefc iece uiagniries about 70 diameters. The vertical circle is graduated to fifteen minute spaces, and its vernier reads to half minutes. The latitude level carries a 2 mm.gradnation of 70 divisions, numbered contiuiioiislyfroiii one end to the other. The time was computed from sextant observations of the sun's altitude. The instrument was usually mounted on a wooden pier, similar to that used for the azininth instrument, but larger and heavier, and covered by a portable tent. At Nogales and at Yuma tlic zenith telescope was mounted upon the brick pier which had previously been used as a latitude pier by the Coast and Geodetic Survey longitude party. The mean places -of the stars observed for latitude were furnished in advance by Prof. T. IT. Safford, of Williams College, Williamstown, Mass. (See catalogue in report of United States section.) The value of micrometer was determined at every station except at No. 14 by transits across the thread of polaris near elongation, the thread being set at each half turn in succession for the twenty turns near the middle of the field of the telescope, and the time of transit observed by eye and ear. The following table gives the results for latitude by the United States section : Latitude results of Vnited States section. No. of United states station. ment. Number ofnigbts. Instrument used. Number of obser- Results for lati- tude. Probable error. Observer. 15 26 40 * Zenith telescope.. 67 39 40 130 99 102 99 100 101 106 126 121 105 25 96 31 46 59.40 60.34 58.08 59.72 31 19 61.79 57.94 56.86 58.99 66.07 64.67 57.58 60.73 32 43 34.69 32 29 .91 32 32 1.34 ±0.00 ± .07 ± .05 ± .04 ± .04 ± .04 J- .04 ± .03 J- .03 ± .04 i .03 ± .04 ± .03 ± .08 ± .04 J. F. Hayford. Do. Do. Do. Do. Do. Do. Do. Do. Do. Do. Do. Do. Do. Do. do 67 77 do do do ■.:■■::■■"■ 98 do 111 4 12'' 5 To 4 dn 26 UNITED STATES AND MEXICAN BOUNDARY. UNITED STATES AZIMUTH OBSERVATIONS. All the azimuth observatious were made with Fautli repeating' theodolite No. 725. The hori- zontal circle, 25 cm. (10 inches) in diameter, is graduated to 5' spaces, and is read by two opposite verniers to 5", It is furnislied, on the horizontal motions, with axis clamps and tangent screws working against spiral springs. The telescope has a focal length of 41 cm. and an objective 45 mm. in diameter. The eyepiece used magnifies about 30 diameters, and is furnished with a micrometer with which the azimuth observations were made, except at Monument 53, where the azinmth was measured on the horizontal circle by repetitions. Tlie theodolite was mounted on a wooden pier in the large observatory tent. The pier was a hollow, triangular column, built of 3-inch pine, put together with screws and banded at top and bottom with heavy hoop iron. The pier was set as a fence post at eacli station, about 45 cm. of its length being below ground. The earth was tamped solidly around it, and its hollow interior was also lilled with earth to give it greater rigidity. Tlie mark used for azimuth work was an ordinary bull's eye lantern showing through a hole an inch iu diameter in front of the small box which served to protect it from the wind. This light was placed from 1 to 3 miles from the theodolite at each station. The time was obtained with sufficient accuracy for the azimuth work by sextant observations of the sun's altitude. With the exception of one station all the azimuth observatious were taken with the eyepiece micrometer by the method described in Bulletin No. 21, December 12, 1890, of the Coast and Geodetic Survey. All the observatious were taken near elongation, usually witliin one hour, and polaris was used at each station. Tlie azimuth light having been previously placed nearly in the vertical plane of the star, the observations consisted simply of the measurement with the eyepiece micrometer of the small horizontal angle between the star and mark, the chronometer time of each star pointing being noted. Each set of observations consisted of five pointings on the mark, followed by five on the star, with telescope direct; five more pointing on the star, followed by five on the mark with telescope reversed, completed tlie set. The level was read at the beginning, middle, and end of each set in both xjositions of the telescope. Having determined the azimuth of the mark we need uext to determine the exact location of a point to the westward (or eastward), on the prime vertical of the station, said point serving with the station to fix the direction of the "tangent" to be continued forward to the next station. A point was first placed as uearly in azimuth 90° as could be done by a single pointing and reading of tlie horizontal circle, usually within ten seconds. The distance to this point from the station was measured by chain or stadia, and the angle between the point and the azimuth mark was measured with the theodolite used as a repeater, each set of observations consisting of six repetitious of the angle and six of the explement (360 angle). The linear correction at right angles to the line of sight necessary to place the point in the prime vertical of the station was then computed and the final point set by linear measurement from the approximate point. Azimttih results J>ij ViiHed States section. Locality. Monument No. 1... Monument No. 15 . . Monument No. 26.. Monument No. 40.. Monument No. 53 . . San Luis Monument No. 07 . . Monument No. 77 . . Dutch Cliarley'8... Monument No. 98 . . Monument No. 111. Nog.iles Monument No. 204 . Monument No. 258 . Method used. Nnm- her of sets. Micrometer... ...do ...do ...do Theodolite.... Micrometer... 13 .-..do 12 ....do 10 ...do 12 ...do 27 ...do ....do ...do ....do ....do Kesulta for azimuth. Prohahle Observer. 178 30 40.11 ±0.21 J.F.Hayford. 37.46 ± .25 Do. 178 31 47.46 i .23 Do. 1 26 10.16 ± .34 Do. 89 57 27.40 ± .70 1).,. 1 23 12.93 ± .23 Do. 181 27 55.52 ± .14 Do. 181 28 31.84 ± .19 Do. 181 28 12.96 ± .10 Do. 181 27 56.39 ± .14 Do. 178 31 29.03 ± .20 Do. 178 33 39.19 ± .26 Do. 178 32 1.12 ± .14 Do. 178 31 21.01 ± .21 Do. 181 28 39.30 ± .27 Do. UNITED STATES AND MEXICAN BOUNDARY. 27 ASTUONOMICAL RESULTS BY MEXICAN SECTION. Longitude. — The ]ioints detennined by the Mexican section were: Juarez, Momuneiit ISIo. 1, i^ogales, and Yuma. The first and the last two were determined by reference to the meridians of Tacubaya and Mexico by exchange of signals by telegraph. The chronometer corrections and rates employed were obtained by observations of the transits of stars with a transit instrument, made by Troughtou and Sims, of about 30 inches focal length, and registered by eye and ear at Juarez and by chronograph at Nogales and Yuma. The longitude of Monument No. 1 was obtained from the station at Juarez by exchanges of flashes of light. The following table gives the results obtained for longitude of the dilferent points from Greenwich : Table of longitude resnlta hij Mexican section. No. of astronom- ic-ll Locality. Nuu,ber of nights. Number 1 Method. ' of obser- Eesnlta. vations. Probable Observer. 1.. Juarez (cliurcli) .. Monument No. 1.. No-'ales 3 C 3 ;.. »,i. s. Telegraph 12 7 5 55.98 Lio-ht flashes ' 7 C C. 54 ±0.24 ± .25 + .03 V. Gama. F.Valle. Do. G. B. y Pnga. Telegraph 35 7 23 45.G1 Latitude.^. — Twelve astronomical stations were established at various points on the line for the determination of latitude. At four of these— see the following table— an altazimuth of 12 inches diameter of limb was used, and difference of zenith distance of pairs of stars selected so as to be reduced by the "Talcott method" were observed, except at Monument No. 1, where the latitude was determined by circum-meridian zenith distances. At the eight remaining points the latitude was determined by the "Talcott method," using a zenith telescope of about ;)0 inches focal length. The results given in the following table are reduced to the center of the monument named by measurement, except those given for Station No, 7. and Yuma, where the latitudes correspond to the points of observation : Latitude results iy Mexican section. Monument No. : Monument No. 21 . Monument No. 40 . Monument No. 53 . Monument "No. 64 . Monument No. 98 Monument No. Ill Nogales — Monument No. Yuma Monument No. U at Ti.i us Altazimuth ...do Zenith telescope . Altazimuth Zenith telescope. Altazimuth Zenith telescope . 31 46 59.47 31 47 0.87 31 46 58.85 31 46 59.66 31 20 1.83 31 20 2.60 31 19 59.65 31 20 3.02 31 19 58.27 31 20 0.97 32 43 34.22 32 32 25.26 * This latitude is not exactly that of the astronomical station, but is that of the pile of stones that Sr. Valle mi stock for Monument No. XX. Azimuths.— At nine of the latitude stations there were made observations for azimuth also, and at seven other points observations for azimuth alone were made, making 16 points at which azimuth was observed to be used in tracing the tangents to the parallels and to obtain the azimuth of the oblique lines. The iustrunieiit usually employed was an altazimuth of 12 inches, except at Monuments Nos. 204 and 207, where one of 8 inches was used. 28 UNITED STATES AND MEXICAN BOUNDARY. The nietliort ibllowed was to measure the angle between Polaris and a .signal two or three times in both positions of the instrument, the group thus formed being called a series in the following table : Table of asimuth results by Mexican seetioii. Ko. of astro- 1 noraicalsta- Locality, tioii. 1 Series. Nights., Method used. Besults for azi- muth. Probable error. Observer. Moimmcnt No. 1 Monument No. 2 3 Altazimuth... 191 31 31.2 233 33 23.2 188 34 50. 1 iO.13 + .42 F. Valle. C. A. Gonzalez. F. Vallc. C. A. Gonzalez. r. Valle. Do. Do. Do. Do. Do. Do. D... Do. MonnmentNo.l5 Monument No. 21 Monument No. 40 Monument No. 53 Monument No. 64 Monument No. 83 Monument No. 98 Monument No. 111.... Monument No. XIX.. 3 3 4 3 do ■. do do ......do .....do do do do do do do 176 30 45. 5 ± . 59 269 50 37.8 + .40 2.7 +.96 89 59 57. 5 1 + . 90 90 0. 3 89 59 28.7 3 36 18.0 179 35 59.2 179 30 31.3 181 !9 57.6 109 33 49.5 179 39.8 85 4 44.7 ± .50 ± .37 + .20 ± .73 ±•.39 ± .46 + .51 7 Monument No. 204.... Monument No. 207.... Monument No. 221.... The aziiiinths in this tahle arc couiitctl from the south lij^ tho west. FINAL ASTRONOMICAL RESULTS. Tlie results for longitude as given by the United States section were adopted by the Mexican section. The reason for this was that the United States section determined differences of longitudes, e.xcbangiug observers to ascertain and eliminate their personal equation, and observed the same stars at both stations. The Mexican section determined differences of longitudes with Tacubaya without exchange of observers, and dift'erent stars were observed at the two stations. The results for latitude are given in the following table. The adopted results are (when both sections observed at the same station) the mean, by weight, of the United States and Mexican results from their respective observations. Finul results for latitude. Old No. New No Mexican Station Station No. 9 . 31 46 08.08 31 46 59. 72 31 19 61.79 31 19 57.94 31 19 06.07 31 19 04.67 31 19 57.58 31 19 60.73 32 29 1.00 32 43 34.09 Mexican results. 31 40 59.47 31 47 0.87 31 40 59.40 ,. 40 58.85 - ■"1 31 40 59.60 ± .00 31 19 61.83 * .19 31 19 02.00 ± .14 31 19 :: .05 31 19 03.02 ± .17 31 19 58.27 i .18 31 19 60.97 * .11 32 43 34.22 ± .26 32 32 25.20 * .19 31 40 0U.88 31 40 00.34 31 46 58.85 31 46 58.08 31 40 59.70 31 19 01.79 31 19 57.94 31 19 62.60 31 19 56.86 31 19 58.99 31 19 69. 05 31 19 06.07 31 19 63.02 31 19 57.58 Arizona-Sonora. No monument. California. 32 32 1. 34 Mexican observations made at Monument No. OS ; Unit(^(l States observations made at Salazar's old monument, no east side of San Pedro River, and reduced to Monument No. 98 by triangulation ; hence Mexican result used. UNITED STATES AND MEXICAN BOUNDARY. SECTION y. lu order to identity the existing old momiineuts, as well as to obtain the necessary elements for locating tlie new monuments on the lines forming the boundary, the lollowing geodetic opera- tions were executed: I. Traciug the parallels according to tlie method of taugeuts and ofl'seta. II. Tracing- the meridian section by simple alignment, its direction having been previously verified. III. Tracing the azimuth lines, either by straight lines connecting consecutive existing old monuments directly, or by the aid of auxiliary lines starting at one of these monuments and passing as closely as possible to the next monument. IV. Triangulation made in the vicinity of the initial monument on the Rio Grande by the United States section to refer the initial mcpnumeut to its astronomical observatory, and the reference of the longitude of the initial monument to the astronomical station at Juarez made by the Mexican section by flash signals at night. V. Triangulation made in Nogalcs by the United States section and repeated by the Mexican section to refer Monument No. 127, at the west end of the line on parallel 31= 20', to the astronomical observatory occupied successively by both sections of the commission. VI. Triangulation made in the vicinity of Yuma, Ariz., by the United States section, and repeated by the Mexican section, to refer Monuments No. 20-1 and No. 207 to the astronomical observatory at Yuma, Ariz., occupied successively by both sections of the commission. All the preceding operations were executed independently and at difiereut epochs by the two sections of the commission, the results being compared as soon as practicable after reduction. On parallels 31° 47' and 31° 20' new monuments intervening between two consecutive existing old monuments were located upon a curved line joining the latter, the curvature of this line being as nearly that of the corresponding parallel as possible. On the meridian section and on the azimuth lines the new monuments were located upon the straight lines joining consecutive existing old monuments. In tracing straight lines, as well as in triangulation, heliotropes were generally used for distant signals. In the following tables are given the lines run by the two sections, respectively, and the measured oflfeets to existing monuments from those lines on parallels 31° 47' and 31° 20', and on the azimuth lines: PuraUel Sl° 47'. United States tangent On original survey. Mexican astronom- ital station No. 2 Not shown Not found Not found . United States a No.2 Not found . I 5 United States astro- Monument No. 15 Jnited States as- tronomical sta- tion No. 2. 24.77 122.46 240.10 22.91 Meters. 15.19 15.00 Monument No. 15 . Monuiuent No. 21 . Monument No. 15 No. 21. 1 35.70 30 UNITED STATES AND MEXICAN ROUNDARY. Parallel ST- 47' — Continued. No. of monument. United States tangent. Mexican tangent. j On original survey. New No. No. Begins. Ends. Measured offset. NO. Begins. Ends. Measured ottset. United States. Mexi- 26 21 3 *3 i 4 5 5 5 5 United States as. trononiical sta- tion No. 2. Monument No. 20. MHer.. 58.40 00. 84 10.78 0.00 0.00 2.44 25.20 Meters. nomical station No. 3. 5 6 United Statesastro- nomical station United States as- tronomical sta tionNo.3. do . ... Monument No. 21. do 3 JIoTiumentNo.40. 0.95 United States astro- nomical station No. 3. 6 7 7 8 8 9 United Statesastro- ] nomical station 2C 33 40 do United States as- tronomical sta- tion No. 4. do I 3 Monument No. 21 . Monument No. 40. 9.87 60.72 do do 98.97 63.11 do ^'o-* 1 ■■ > A check tangent was run from United Stales astronomical station No. 2 between Monuments Nos. 15 and 21, giving offsets of 4.14 and 30.30 meters, respectively. Offsets to above points on parallel 31° 47' are aU measured to the north. Meridian lection. The line traced by both sections on the meridian section of the boundary was the straight line joining Monuments ]Sfos. 40, 40, and 53, which had been found to lie exactly in the meridiau. I'arallel St^ 20'. No. of monument. United States tangent. Mexican tangent. i 1 On original survey. r No. 8 8 8 9 Begins. Ends. Measured offset. No. Begins. Ends. Measurci offset. United states. Mexi- can. i 10 11 United States astror 53 United {States as- tion No. 5. United States a.s- tronomical sta- tion No. 6. — 6.49 0.00 ' Monument No. 53 . Monument No. 64. Meters. 0.00 om- do . . United States astro do 60.00 0.00 United States as- tronomical sta- tion No. 6. United States as- tronomical sta- tion No. 7. 12 13 64 Monument No. 04 . Me.xic.in astro- nomical station No. 7. 98.64 0.00 — .57 -129.29 —118.80 —108.56 2 2 2 2 Mexican astro- nomical station No. 6. do do station No. 0. 64 65 06 67 uom- 13 14 15 United Sta 15 16 es astro 9 9 9 9 10 United States as- tionNo.6. United States as- tronomical sta- tion No, 7. do —118. 59 -104. 01 -90.20 -94.24 4.05 do do do do do 15 r ^'"Vr t'bt' United States as- tronomical sta- tion No. 7. United States as. tronomical sta- tion No. 8. UNITED STATES AND MEXICAN BOUNDARY. Paralld SI- ^'6>'— Contiiiueil. 31 No. of monument. ] United States tangent. Mexican tangent. On original survey. Ne» No. Ends. MeasuredNo. offset. 1 Measured offset. United 1 Mejd- States. can. 10 10 10 10 10 11 Begins. Begins. Ends. 73 United States as- tronomical sta- tion No. 7. do do United States as- tronomical sta-. tiouNo.8. Ueters. 0.00 37.51 256. 58 257. 32 258. 13 — 0.73 0.00 Meters. ical static 16 17 nNo.7. 17 2 2 2 Mexican astro- No.O. do Mexican astro- nomical station No. 7. do — 44.54 196. 50 198. 17 do United States astronom- ical station No. 8 18 19 1 V7 United States as- tronomical sta- tion No. 8. do United States as- tronomical sta- tion No. 9. ilo United States astroi 11 ...:!::::::::::. M6\ic->u astronomj'-nl 2 3 Mexican astro- nomical station No. 6. Mexican astro- Mexican astro- IJ') CO station No. 7. 19 20 Mexican astronom 83 cal nomical station No. 7. •MoTi.,,.,„.,f -Mn OB ' 1S7 11 nomical station No. 7. [ do 1 do 0.00 United States astronom- 11 12 12 12 138. 58 0.00 Do United States as- tronomical sta- tion No. 9. Monument No. 98 . StatiouA.tangentNo.ia. 20 21 I 98 1 Station A, tangent No. 13. do 59.06 51.47 0.00 do Station A, tan- genfcNo. 13. MouumentNo.lU 3 Mexican astro- nomical station No. 7. Monument No. 98 . 379.78 i 4 1 Meviran atnlion 1 1 Monument No 111 n nn . station X 20 21 22 United Stat .8. 21 \ 98 22 106 13 Station A, tan- gent No. 13. do MonumentNo.lll do do — 7.62 —110.33 4 ■i 4 4 4 .^'i. do do do do .33 -97.04 - 89. 19 es astronom- do do — 66. 18 — 59.97 0.00 6.20« ilo 23 24 lU 13 :::::d: ;::::::::::; — 43. 01 United States as- tronomical sta- tion No. 11. United States as- tronomical sta- tion No. 12. ical station No. 11. 14 14 14 14 14 15 15 15 5 Mexican .slatiou No. 9. Monument No. 127 3.43 0.00 Mexic-tn as station Nc tronomical do do 5 5 do do 118.56 17.17 0.00 12.33 — 24. 63 117.66 United States astror cm- Do United States as- tronomical sta- tion No. 12. do Monument No. 127 26 27 27 122 127 5 Mexican station No. 9. do Monument No. 127 ---•do 29.70 32.86 do do Ou parallels 31° 47' and Sl*^ 20' ofle measured in th( = ToN. = ToS. 1 lueridiau. UNITED STATES AND MEXICAN BOUNDARY. Sonora azimuth line. LDfES TRACED BY UNITED STATES SECTION. LINES TRACED 1!V MEXICAN SECTION. [-=ToS.] tho grealost oliaets to No. of monument on original survey. Now No. Begins. Ends. Measured offset. rnite.l States. Mexican. 27 XVIII XVII XVI XV XV XIV 127 129 136 137 141 141 146 127 141 Meters. 0.00 0.00 —29.49 —34. 20 XVIII XVII XVI XV XV XIV 1 141 146 -6.00 .146 1m Munu , 204 tlie lines traced were practically tho straiglit lines joining the accepteil existiu California azimuth line. No. of monument. TTnitod States line. j Mexican lino. On origi- nal 1 New No. survey. , No. Begins. Ends. Meas- ured off- set. No. Begins. Ends. Meas- ured off- set. VII.... VI V IV IV HI (*) 207 220 221 221 1 Boundary post.... do do Between monu- ments Nos. 230 and 231 Meters. .00 .00 +32 55 Meters. no do 1 2 do do Monument No. 221. do Between monu- ments Nos. 230 and 231. do MonumentNo.247 do do +34 30 do +30. 40 do Between monu- + 32.11 +32 U menls Nos. 230 and 231. —18. 32 —25. 80 +62. 20 +62.20 .00 231 2 247 2 247 i 3 ments Nos. 230 and 231. do MonunicntNo.247. do MonumentNo.247. do MonumentNo.252. do -25.80 3 + 62.14 3 +02. 14 ; 4 MonumentNo.247. do do III ...1 2.')2 1 4 Monument No. 252. Monument No II fin 251 5 5 5 Monument No. 251 . MonumentNo. 258- do do +11.91 + 1.69 .00 1 II 4 Monument No. 252. Monument No. II. .00 257 do do 5 Monument No. II. Monument No. 258. do .00 .00 I 258 5 MonumentNo. 251 MonumentNo. 258. - .57 + = ToN. +=ToN. — =ToS. — = ToS. ■ Boundary post. Ou the Souora and (California azimuth liuus oflsets aro lueasureil at right angles to thu line as run. OPERATIONS OF THE MEXICAN SECTION. With the exception of some distances which, on account of the character of the country, were nieasnred directly by steel tape or by means of small triangles, the measurements along the boundary line were made by stadia. The offsets for points in tho parallel were measured with a steel tape in the corresponding meridian which had been previously laid oft' with a small theodolite. UNITED STATES AND MEXICAN BOUNDARY. 33 OPERATIONS OF THE UNITED STATES SF.f'TION. Ou parallel 31° 47' distances along tangents were measured by both chain and stadia. All other distances along the boundary line were measured by stadia. The meridians in which were measured offsets to points in the i)arallels were obtained by turning off from the tangents angles dependent on the azimuth of the corrected tangent at the point. Offsets were measured with a steel tape in the meridian so obtained. All distances were reduced to mean sea level of San Diego Bay by means of a line of levels carried by the United States section from the Eio Grande to the Pacific. JdINT OPERATIONS. The triangulations made by the United States section and checked by tlie Mexican section at Monument No. 1, on the Kio Grande, Nogales, and Yuma, are as follows: DETERMINATION OF LONGITUDE OF MONX'MENT NO. 1, UNITED STATES TRIANUULATION. A base was measured on the railroad near Astronomical Station No. 1, and a triangulation laid out by the United States section from this base, connecting Astronomical Station No. 1 with Monuments Nos. 1, 2, audo, the magnetic station near ]MonumentNo. 1, the longitude station at El Paso; also with the public buildings in El Paso and Juarez. By this triangulation the difference of longitude of Monument I^o. 1 from the longitude station at El Paso is + L" 18.78", making the longitude of Monument N<'. 1, 100"^ ;U' 39.03". MEXICAN DETERMINATION BY PLASHES. The longitude of observatory at Juarez was transferred to Monument No. 1 by the Mexican section by flashes, the difference between those points being + 2' 45.75", making the longitude of Monument No. 1, 106' 31' 38.10". TRIANOULATION AT NOGALES. A base line of 724,90 meters was carefully measured at night on the railroad at Nogales, Mexico, and a triangulation made connecting the astronomical station at Nogales, Ariz., with the azimuth station and monuments Nos. 122 and 127. This triangulation was repeated by the Mexican section. l\esiiU« (if Iriangulation. Latitude. LongiUule. 1 31 2U 4.70 31 20 0.7.5 31 19 59.30 Monument No 122 1 10 56 34 33 Monument No 127 111 4 34.46 TRIANGULATION NEAR YUMA, ARIZ. A base of 2,203 meters was measured by the United States section, checked by the Mexican section afterwards, and an extensive system of triangulation made connecting the astronomical station in the corral of the United States Quartermaster's Department, occupied by both the United States and Mexican astronomical parties for latitude and longitude, with the azimuth station of both sections, with Monument No. 207 on we.st side of the Colorado River, and with Monument No. 204 on the east side of the same river 20 miles below the junction of the Gila and Colorado. This triangulation was repeated by the Mexican section. S. Doc. 247 3 34 UNITED STATES AND MEXICAN BOUNDARY. The results of this triangulation are: I — Longitude. ! - ,. 114 37 23.40 114 37 7.44 114 36 56.61 114 46 48.64 114 43 54.31 32 43 29 64 Monument No. 204 32 29 1.03 Previous to commencing the erection of monuments it had been agreed that when the meridian of the site had been selected iu the field the corresponding distances from the pext preceding monument site to this meridian would be compared, and if found to differ more than one three- hundredths on parallel 31° 47', the meridian section, parallel 31° 20', and the Sonora azimuth line, or more than one flvehuudredths on the California azimuth line, they would be remeasured. Each section would then, from its own tangent or auxiliary line, lay off on the ground in this meridian the computed position of the monument. If the meridian distances of the points so located differed less than 2 meters it was agreed that the mean ijosition would be taken as the true position. Should this dift'erence exceed 2 meters the corresiJonding tangents or auxiliary lines were to be retraced. The agreed limits as to distances and oflsets were strictly adhered to except iu one case each — the discrepancy between the United States and Mexican measurements of the distance between Monuments 185 and 180 being one two-hundredand-seveutieth, and in their offsets at Monument 191 being 2.04 meters. As both of these cases occurred on the desert, where water was difficult to obtain, and where remeasuremeuts would have caused serious delay, and as they exceeded the limit but slightly, it was considered best, in the interests of the work, to accept these discrepancies rather than to attempt remeasuremeuts under such adverse conditions. The distances between monuments obtained by each section sejiarately were compared, and the mean of the measurements of the two sections taken as the true measurement. This result was then reduced to mean sea level of San Diego Bay, California, by the usual geodetic formula, employing the elevations given by the line of levels of the United States section. The distances thus obtained (with the exception of those on the meridian .section) were adjusted — in the parallels to the astronomical longitudes of their extremities, and on the Sonora and California oblique lines to the astronomical longitudes of their extremities and the observed azimuths. The results of these reductions are shown in the following tables, and in addition are shown the difference, in a north and south direction, between the United States and Mexican locations of the monument site, and also the character of the monument erected. fii (lislanCL-s, in mctem, between ts on ],a -allel 31"^' 47'. Distance l)etwcen monnments. Reduc- tion to level." Reduced distances. Mex. No. of monument. United States. Mexican. Mean. To mean sea level. with astro- nomical distance. from 1J.. , „ ,„,„„, 1 1 Masonry. Do. Do. Solid iron. 4,202.76 7, 568. 61 7, 527. 66 7, 930. 11 7,703.02 7,876.59 1 400 39 712.1 7,563.5 7, 533. 7 7,931.6 7,704.3 7, 870. 1 1,400.3 7, 010. 9 7,791.5 711.89 4, 260. 83 7,566.05 7, 530. 68 7,930.86 7, 703. 66 7,873.34 1,400.35 7,011.03 7,794,65 — 0.14 — .81 — 1.48 — 1.47 — 1.65 — 1.51 — 1.54 — .28 — 1.37 — 1.53 711.75 4,260.02 7, 564. 57 7,529.21 7,929.31 7, 702. 15 7, 871. 80 1,400.07 7,010.26 7, 793. 12 713.4 4,270.3 7,682.7 7,547.3 7,948.3 7,702.7 7,890.7 1,403.4 7, 027. 1 7.811.8 3 +0.36 5 6 + 1.04 Do. + .94 Do. + .03 Do. 9 10 11 7,012.36 7,797.80 —1.39 Do. Mascmry. UNITED STATES AND MEXICAN BOUNDARY. Final distances, in meters, heticeen monuments on parallel Sl° 47' — Continued. 35 . of monument. Distance between monumentf 5, 094. 78 6, 920. 12 4,671.24 3,281.42 1,657.06 6,906.2 4,675.2 3, 284. 1 5,094.79 6,913.16 4, 673. 22 3. 282. 76 1,656.88 4, 339. 92 3, 875. 05 3, 970. 52 3,969.2 3,969.86 3, 430. 65 3,431.2 3,430.93 1,991.14 1,99V 7 1,992.42 1,609.44 1,610.2 1, 609. 82 4, 437. 34 4,434.4 4,435.87 3, 815. 76 3,820.9 3,818.33 1,328.39 1,328.7 1,328.54 3,094.45 3,092.1 3,093.28 3,523.44 3, 531. 3 3, 527. 37 3,676.90 3,675.7 3,676.30 4, 300. 20 4,305.0 4, 302. 60 3, 430. 16 3,427.0 3,428.58 2,433.47 2,440.4 2,436.93 1,142.99 1,144.3 1,143.65 4, 149. 30 4, 160. 2 4, 154. 75 4,541.29 4, 535. 4,538.15 3,700.68 3,702.0 3, 701. 34 3, 000. 55 2, 999. 2,999.77 2,592.28 2,592.2 2,592.24 2, 775. 39 2, 780. 7 2,778.04 2,053.88 2,057.4 2,055.64 158, 828. 97 I 158, 858. 8 158, 843. 89 level. Eeduced distance. with astro- nomical distance. Hex. from U.S. 'e 5, 093. 80 6,911.82 4,672.31 3,282.11 1,656.36 4,339.09 3,874.31 \ 4,208.96 I 3,969.11 3,430.28 1,992.03 1,609.51 4, 434. 99 I 3,817.57 j 1,328.28 3, 092. 65 I 3, 520. 65 3, 675. 55 4, 301. 72 3,427.88 2, 436. 43 1,143.42 4, 153. 85 4, 537. 15 3,700.53 2, 999. 12 2, 591. 68 2, 777. 44 2, 055. 19 31.64 158,812.25 3, 978. 6 3, 438. 5 1, 996. 8 1,613.4 4,445.6 3, 826. 7 1,331.5 3, 100. 1 3, 635. 1 3,684.4 4, 312. 1 3, 436. 1 2, 442. 3 1, 146. 2 4, 163. 8 4, 548. 1 3, 709. 4 3, 006. 4 2, 597. 9 2, 784. 1 + .63 - .31 .00 _ ..38 + .28 4- .81 + .62 + .08 _ .14 4- .01 - .04 + .03 + .28 + .36 _ .40 - 33 ...... "u + 48 + 66 Masonry. Solid iron. Do. Masonry. Solid iron. Masonry. Solid iron. Do. Final distances, in meters, hetwaen monuments on the Meridian section. No. of monument. Distance between monuments. Reduc- tion to meansea Distance reduced to level. Kindofmonu- Masoury. .Solid iron. Do. Do. Do. Do. Masonry. Solid iron. Do. Do. Do. Do. Do. Masonry. l^t Ue.icau. Mean. 40 1 3,327.38 4. 449. 05 3,564.70 3,689.32 4, 747. 35 4, 765. 63 4, 773. 77 3,894.98 4,442.75 4,381.53 4,043.01 3,321.38 542. 20 3, 329. 1 4,448.4 3,560.2 3, 690. 96 4,7.52.59 4.751.0 4,774.05 3,l!82.4 4, 443. .58 4, 382. 88 4,055.2 3, 321. 2 3, 328. 34 4,448.73 -0.71 1.3,327.63 0.0 .0 .0 .0 .0 .0 .0 .0 42 .95 3,501.69 .I, 689. 35 4,748.99 4,757.55 4,772.91 3, 887. 87 4, 442. 25 3,690.14 — .70 43. 4,758.57 4,773.91 3,888.69 4,443.17 4,382.20 4,049.11 3,321.29 - 1.00 - .82 - .92 49... 51 .92 .,ooi.^o — .85 4,048.26 53 542. 1 „,.,. i„ [ . i„ 1 j„. u„ 49, 943. 27 4 , 4. b ' , - . 36 UNITED STATES AND MEXICAN BOUNDARY. Final distances, in meters, between monuments on parallel 31° SO'. Distance between monuments. 3, 313. 58 4, 987. 87 3, 324. 08 6, 096. 10 1, 125. 31 2, 529. 39 3, 794. 68 5, 679. 31 4, 036. 72 3, 487. 51 1, 967. 75 .■;, 987. 34 4, 675. 14 1,326.86 1,797.34 1,871.46 6, 060. 61 3, 983. 66 4,449.98 6,319.34 0,685.44 3,467.42 3, 991. 16 5, 153. 64 5, 693. 59 4, 46(1. 52 3, 308. 49 3, 474. 68 3, 074. 18 5, 114. 18 2, 355. 49 2, 787. 47 6,492.22 2,930.34 1,527.71 3, 559. 15 3,330.01 2,018.42 2.682.37 6, 120. 64 3, 976. 70 6,763.40 2, 138. 4y 3,613.50 5,605.20 6,469.70 5,774.46 2, 188. 43 3,333.79 4,011.83 6, 168. 40 5,401.90 4, 803. 00 3,313.60 4, 979. 80 3, 324. 29 0, 084. 35 1,128.98 2, 533. 60 3, 790. 80 5, 677. 70 4,031.20 3, 478. 60 1,965.88 5, 987. 71 4,681.49 1,329.46 1,795.05 6,060.23 3, 982. 49 4, 437. 85 C, 331. 68 6, 684. 92 3, 458. 70 3, 990. ( 4. 464. 65 3, 309. 24 3, 475. 46 3, 073. 04 3, 624. 14 3,344.71 4,990.13 4, 853. 93 441. S l,731.t 5, 115. C 2, 349. 64 2, 790. 62 i 6,470.68] 2, 925. 70 1,526.96 [ 3.554.85 i 3, 326. 10 2.021.40 2,675.87 6, 106. 53 3,981.09 6, 768. 25 2, 138. 12 3,617.22 5, 609. 66 2. 092. 89 6, 476. 55 5, 774. 95 2, T 90. 38 3, 334. 02 4, Oil. 83 6,175.93 5, 403. 80 4, 808. 23 3, 313. 59 4,983.84 3, 324. 18 0, 090. 22 1,127.15 2, 531. 49 3, 792. 74 5,678.51 4,033.90 3,483.05 1,966.82 I 5,987.53 ! 4,678.31 1,328.16 1, 796. 20 1,870.34 6,060.42 3,983.07 4, 443. 92 6,325.51 6, 085. 18 : 3, 463. 00 3, 990. 58 5. 148. 47 6, 693. 35 4, 462. 58 3, 308. 87 3,475.07 3, 073. 01 3, 623. 94 3,345.12 4, 992. 72 4,858.00 442. 42 1,729.37 5,114.1 2,352.57 2,789.04 6,481.45 2, 928. 02 1,527.33 3, 557. 00 3. 328. 05 l^educed distances. To agree with as- tronomical distance. 6,766.63 2,137.61 3,016.35 5, 608. 32 2, 092. 39 6, 475. 00 5,773.56 2,189.86 3, 333. 19 4,010.89 6,174.45 5, 402. 51 4, 807. 08 3,312.80 4,982.64 3,323.38 6,088.76 1, 126. 88 2,530.88 3,791.92 5, 677. 29 4,033.09 3,482.30 1,966.40 5, 980. 24 4, 677. 30 1, 327. 87 1,795.81 1,869.94 6,059.11 3, 462. 31 3, 989. 72 5, 147. 36 5,692.12 4,461.62 3, 308. 16 3. 474. 32 3, 072. 95 3, 623. 16 3,344.40 4, 991. 64 4, 856. 95 442. 32 1, 729. 00 5,113.53 2,352.06 2,788.44 6,480.( 2, 927. 39 1,527.C 3,556.23 3, 327. 33 2,019.48 2, 678. 1 6, 112. 27 3, 981. 7 6, 769. 3 2,138.4 3, 617. 8 5,610.6 2,093.2 6,477.6 5,775.9 2,190.7 3,334.5 4,012.5 6, 176. 9 5,404.7 Mex. U.S. ^- 6,091.2 I 1, 127. 3 2,531.9 j. 3, 793. 4 6,326.7 6,686.4 3, 463. 7 3,991.3 5, 140. 4 3, 475. 7 3, 074. 2 3, 624. 6 3,345.' 4, 993. 6 4,858.9 442.5 1,729.7 5, 115. 6 2,353.0 2,789.6 6, 482. 6 2, 928. 6 1,527.6 3, 557. 6 3, 328. 7 --.19 + 1.14 M.i.sonrj'. Solid iron. Do. Do. Sectional iron. Solid iron. .11 Section.-il iioi 4, 034. 7 -.37 Do. Masonry. Solid iron 1, 967. 2 — .43 5, 988. 6 — .22 Do. 4,679.2 —1.60 Sectional 1,328.4 -.19 Do. 1,796.5 Masonry. 1, 870. 7 -.44 Solid iron Do. Do. Masonry. Solid iron. Sectional iron. Do. Do. Solid iron. Masonry. Solid iron. Maaonry. Solid iron. Do. UNITED STATES AND MEXICAN BOUNDARY. 37 meters, betiveen monuments on parallel 31° 20' — Continueil. No. of monu- ment. Distance between monuments. Reduc- tion to ""level" Reduced distances. Mei. from Kind of monument. United States. Mexican. Mean. To agree To mean with as- sea level, tronomical distance. 114 115 116 117 118 119 120 ... 121 1,994.22 3,044.31 3,862.46 4, 145. 24 1,865.96 5, 149. 38 2,471.31 1,075.72 256.70 *I, 922. 09 -3,062.83 ♦3,067.06 *4, 403. 16 231.82 1.990.28 1,992.25 3,046.91 \ 3,045.61 3,862.43 3,862.44 4, 141. 65 : 4, 143. 45 1.864.60 1,865.28 5,135.23 1 5,142.30 2,471.31 2,471.31 1,075.73 , 1,075.73 256.70 256.70 1.917.29 1,919.69 — .43 — .66 — .83 — .89 — .40 — 1.11 — .54 — .24 — .05 *— .40 1.991.82 3,044.95 3,861,01 4, 142. 56 1,864.88 5, 141. 19 2,470.77 1,075.49 256. 65 1,919.49 3.062.71 3, 066. 13 4,403.45 1,992.6 3,046.2 3,863.2 4, 144. 2 1,865.6 5,143.2 2,471.8 1,075.9 256.8 1,920.2 3,063.9 3,067.4 4,405.2 — .31 + .48 -1- .35 -1-1.03 Sectional iron. Do. Do. Solid iron. Masonry. Solid iron. Do. Do. Do. Do. Do. Sectional iron. -(- .63 + .04 — .48 m + .65 -1- .76 + .31 — .31 3,063.24 3,063.03 *- .64 3,065.84 3,066.45 *- .64 4,404.65 4,403.91 j *- .92 125 126 Total 273,017.51 272,792.30 272,904.90 1 -60.77 272,845.43 272,954.2 * Distances marked as above were determined by triaugalation. Final distances, ire meters, hetween monuments on the Sonora azimuth line. No. of monn- Distance between monuments. Reduc- tion to mean^sea Reduced distances. -S.) Kind of United States. Me-Kican. Mean. To mean sea level. To agree with as- tronomical distance. , Masonry. Sectional iron. Masonry. Sectional iron. Do. Do. Do. Solid iron. Do. Masonry. Do. SoUdiion. Do. Do. Masonry. SoUd iron. Do. Do. Do. Masonry. Solid iron. Do. Do. Masonry. Solid iron. Do. Sectional iron. SoUd iron. Do. Do. Do. Do. Sectional iron. Masonry. Solid iron. Masonry. 394.11 5,647.28 3,665.60 5,688.13 5,341.67 2,528.45 3,053.65 6,173.87 2, 529. 90 4.236.79 4,569.35 3, 592. 49 4,568.86 2,028.56 5,518.10 5,632.46 4, .535. 78 5,523.13 6,370.76 7, 270. 59 3, 884. 47 4,663.77 4,062.76 3,606.87 5,236.91 4,557.97 5,989.55 5,294.19 5,387.32 4,668.84 3,953.42 3,840.63 4, 069. 36 1,989.95 5,295.83 393.51 5.637.35 3, 660. 18 5,696.30 5,354.61 2,534.23 3,045.46 6,184.13 2,533.84 4, 240. 52 4,565.38 3,591.21 4,569.25 2, 028. 87 5,524.90 5, 631. 96 4,531.78 5,529.98 6,369.38 7,290.63 3,892.10 4,658.48 4,053.55 3, 604. 20 5,237.71 4, 569. 21 5,977.44 5, 293. 77 5,379.85 4, 662. 30 3,952.35 3,839.24 4,061.88 1,988.10 5,281.81 393. 81 5,642.32 3,662.89 5, 692. 21 5,348.14 2, 531. 34 3,049.55 6, 179. 00 2,531.87 4,238.66 4,567.36 3,591.85 4,569.06 2,028.72 5, 521. 50 5,632.21 4,533.78 5,526.55 6,370.07 7,280.61 3,888.28 4,661.12 4, 058. 15 3,605.54 5,237.31 4,563.59 5, 983. 50 5,293.98 5,383.58 4,665.57 3, 952. 88 3,839.93 4, 065. 62 1,989.02 5,288.82 — 0.10 — 1.33 — ■'" I'-z — .59 -1.21 — .49 — .77 — .81 — .63 — .81 ::» — .77 — .61 — .75 — .88 — .94 — .50 — .60 — .52 — .34 — .49 — .56 — .50 — .51 — .44 _ .37 — .36 — .38 _ .19 1 - •^» 5,640.99 3, 662. 19 5. 691. 10 5, 347. 10 2,530.85 3, 048. 96 6,177.79 2,531.38 4,237.89 4,566.55 3,591.22 4, 568. 25 2. 028. 36 5, 520. 75 4, 533. 17 5,525.80 6,369.19 7,279.67 3,887.78 4, 660. 52 4,057.63 3,605.20 5,236.82 ?,503.16 5,982.94 5,293.48 5, 383. 07 4,665.13 3,952.51 3,839.57 4,065.24 1,988.83 5,288.32 393.5 5.638.0 3, 660. 2 5,344.3 2,529.5 3, 047. 3 6, 174. 5 2,530.0 4. 235. 6 4,564.1 3,589.3 4,565.8 2,027.3 5,517.8 5,628.4 4, 530. 8 5,522.8 6,365.8 7,275.8 3,885.7 4,658.0 4,055.5 3,603.3 5,234.0 4,560.7 5,979.7 5,290.7 5,380.2 4,662,6 3,950.4 3,837.5 4,063.1 1,987.8 5,285.5 + 0.01 + .18 + .06 + .04 + .01 .00 130 '!! .00 .00 139 140 142 .06 — .15 .00 145 146 .00 — .09 .00 .00 .00 .00 -H.07 -^- .05 -1- .07 -1- .18 — .05 — .06 152 153 154 155 156 158 -f.02 161 38 UNITED STATES AND MEXICAN BOUNDARY. Final (liatanceK, i Distance between monuments. 1,968.40 5, 197. 70 0,084.31 2, 945. 70 4, 758. 30 2,480,73 5,05,^51 4,467.84 3,365.58 4,475.31 5, 781. 93 3,275.28 4,931.43 4,286.88 0,014.37 7, 695. 93 4,097.74 5,705.80 7, 713. 33 7,298.47 7, 907. 79 4,215.93 4, 496. 87 4, 490. 74 4, 007. 18 7, 830. 22 6, 278. 96 3,554.76 3,259.00 3,139.33 5,381.94 5,726.85 3,124.20 5, 938. 12 7, 240. 19 7,776.79 7, 597. 09 7, 555. 07 6,409.00 4, 734. 12 4, 067. 87 4, 189. 56 3, 000. 00 1,967. .52 5, 205. 03 6, 085. 08 2,911.98 4, 747. 01 2, 477. 06 5, 046. 08 4, 461. 05 3, 370. 33 4,467.08 4, 284. 38 6, 007. 58 7. 688. 09 4, 698. 41 5, 696. 27 7, 709. 49 4,495.45 4,513.41 4, 003. 02 7, 816. 14 6, 204. 56 3, 547. 80 3,250.39 3, 1.39. 33 5, 375. 01 5, 722. 94 3, 127. 16 5, 938. 15 7, 228. 81 7, 773. 80 7, 593. 77 7, 567. 29 0, 396. 94 4, 725. 07 4, 058. 10 4, 183. 50 3, 000. 00 376,099.6 375,906.6 376, 1, 967. 96 5,201.40 6, 084. 09 2, 943. 84 4, 7.52. 05 2,478.89 5, 051. 10 4,464.44 3, 367. 95 4, 471. 21 5, 777. 66 3,271.93 4, 928. 27 4, 285. 63 0, 010. 98 7, 692. 01 4,698.07 5,701.04 7,711.41 i 7,295.91 7,902.57 4,212.50 4,496.16 4,505.07 4,005.40 7,823.18 6,271.76 3, 551. 28 3,254.70 3, 139. 33 5, 378. 48 5, 724. 89 3, 125. 71 5, 938. 13 7, 234. 50 7,775.30 7,595.43 7, 561. 18 6, 402. 97 4, 729. 60 4, 662. 98 4, 186. 53 Keduced distances. 1, 967. 81 5, 201. 01 6, 084. 24 2, 943. 03 4, 752. 30 4, 404. 19 3, 367. 76 4, 470. 96 5, 777. 33 3, 271. 74 4,927.99 4, 285. 43 6, 010. 70 7, 091. 00 4,697.85 5, 700. 78 7,711.0.5 7, 295. 57 7, 902. SI 4,212.31 4, 495. 95 4,504.86 4, 005. 21 7,822.82 6, 271. 47 3, 551. 12 3, 254. 54 3, 139. 19 5, 378. 25 5,724.06 3, 125. !,9 5, 9:17. 92 7, 234. 27 7, 775. 08 7, 595. 25 7, 501. 02 0, 402. 87 4, 729. 53 4, 662. 92 4,186.49 3, 000. 00 -31.46 ] 375,971.6 To agree with .as- tronomical distance. Mex. V. S. pt. 0, 048. 1 4, 461. 8 3, 366. 5, 774. 2 3, 270. 4, 925. 4 4, 283. 1 6, 007. 5 7, 687. 6 4, 695. 3 5,697.7 7,706.9 I 7,291.7 7.898.0 I 4, 210. 1 4, 493. 5 4, 5U2. 5 4, 003. 1 7, 818. 6 6, 268. 1 3,549.2 3, 252. 8 3,142.4 5, 383. 8 5, 730. 6 3,128.8 5, 944. 7,241.7 7,783.1 7. 603. 1 7, 568. 8 6, 409. 5 4,734.4 4, 667. 7 4, 190. 8 3, 000. + 2.04 +1.96 Masonry. Solid iron Masonry. Solid iron. Do. Sectional iron. Solid iron. Sectional iron. Sectional i Solid iron. Final distanoes, in meters, between monuments on the California azimuth line. No. of monu- ment. Distance between monuments. Kediic- tion to mean sea level. Eeduced distance. Mex. from TJ. S.pt. (+If. -S.) Kind of monument. United States. Mexican. Mean. To mean sea level. ^itK« tronoraical (Ustance. 0.00 Solid iron. Masonry. Solid iron. Do. Do. Do. Do. Do. 809.04 3, 348. 02 0,364.66 7,048.50 4, 309. 53 4,241.70 4,718.03 809. 73 3,352.41 6, 353. 99 809. 38 3,350.22 R 359 39, 0. 00 809. 38 - .02 3,350.20 — .08 : 6,359.24 - .07 7,049.33 — .03 4,313.73 02 4 239 20 809.4 3, 356. 6, 370. 2 7,061.5 4,321.2 4, 246. 6 4,729.8 209 ... + .92 + .40 + .50 + 1.48 + 1.14 + .38 210 211 7,050.29 i 7,049.40 4, 317. 98 4, 313. 76 4 236 75 4 'aa 22 213 4, 725. 28 4, 721. 66 — .03 4.721.63 UNITED STATES AND MEXICAN BOUNDARY. Final distances, in meters, between monuments on the California azimuth Jim- — Continued. 39 Distance between mo numents. 1 sea 1. Reduced distance. " United States. Mexican. 1 tion I^ZT^. ^V^tK^ tronomioal distance. fiJ*- n,onmne1t 6. 175. 85 6. 181. 82 6,178.83 1 — 04 6, 17S. 79 6,189.5 + . 28 1 Solid iron. 5. 379. 43 5. 382. 96 5,381.20 ; — 01 5.381.19 5, 390. 5 + .22 Do. 6,588.48 6,584.64 6,586.56 ] _ 01 6, 586. 55 6,598.0 + .32 Do. 6,461.52 6, 467. 22 6,464.37 — 01 6,464.36 6, 475. + .44 Do. 5,215.11 5,214.71 5,214.91 — 01 5, 214. 90 5, 223, 9 + .36 Do. 4,713,20 4,721.84 4,717.52 00 4, 717. .52 4,725.7 + .26 Do. 5,414.83 5,407.42 5,411.12 00 5,411.12 5, 420. 5 Sectional iron 2,777.00 2, 774. 16 2, 775, 58 00 2, 775. 58 2,780.4 i Do. 7,074.85 5,178.35 7,080.72 5. 169. 00 7,077.79 5, 173. 67 00 00 7,077.79 5, 173. 67 7,090.1 5. 182. 6 + .04 — .30 Solid iron. Do. 6,557.87 6,558.38 6,558.13 00 6, 558. 13 6,569.5 - .44 Do. 1 , 877. 03 1,877.03 1.877.03 — 02 1,877.01 1,880.3 — .52 Do. 4,359.80 4,355.10 4,357.45 - 06 4,357.39 4,364.9 — .66 Do. 4,292.76 4, 285. 70 4,289.23 — 06 4,289.17 4,296.6 — .26 Do. 5,868.36 5,861.63 5,865.00 - 08 5,864.92 5,875.1 - .52 Do. 5,007.86 5,005.03 5,006.44 - 15 5. 006. 29 5, 015. — . 80 ! Sectional iron 7, .524. .35 7,516.71 7,520.53 _ 44 7,520.09 7,533.1 - .98 Do. 7,486.58 7,472.60 7,479.59 — 1 11 7,478.48 7, 491. 4 -1.24 1 Do. 4, 924. 38 4,933.40 4, 928. 89 — 83 4,928.06 4,936.6 -1.18 Solid iron. 4, 555. 62 4,555.99 4,555.80 - 66 4,555.14 4,563.0 -1.04 1 Do. 4,097.08 4,104.50 4, 100. 79 — 59 4,100.20 4,107.3 — .98 Section.al iron 4,099.58 5,009.59 5,004.59 — 80 5,003.79 5,012.5 - . 90 1 Do. 3,620.45 3,620.84 3, 620. 64 — 61 3,620.03 3,026.3 — .08 Solid iron. 4.154.26 4,151.62 4,152.94 - CO 4,152.25 4,159.4 -.76 1 Do. 2, 8B6. 08 2,858.91 2,857.50 — 48 2,857.02 2.862.0 — .70! Do. 4,177.97 4, 179. 99 4,178.98 - 69 4,178.29 4.183.5 -.66| Do. 3,055.94 3,055.94 3,055.94 — 41 3,055.53 3,0C0.S — . 50 Do. 1,859.92 1, 861. 68 1,800.80 - 24 1, 860. 56 1, 863. 7 — .58 Sectional iron ■ 4, 713. 90 4. 710. 30 4, 712. 10 — 64 4,711.46 4,719.6 — .12 Do. 5,122.38 5,120.51 5,121.45 - 46 5, 120. 99 5, 129. 9 - .48 Solid iron. 1,641.46 1,641.49 1,641.47 — 16 1,641.31 1, 044. 2 - .48 Do. 3, 649. 83 3, 654. 90 3,652.37 - 34 3,052.03 3,658.4 — .42 Do. 3,025.12 3,031.58 3,028.35 - 37 3,027.98 3, 033. 2 - .26 Sectional iron 864.54 864.54 864.54 - 10 864.44 865.9 — .20 Do. 3, 665. 12 3, 665. 12 3,665.12 — 32 3, 664. 80 3, 671. 2 - .20 Do. 3,103.51 3, 106. 16 3, 104. 83 — 10 3,104.73 3. 110. 1 — .22 Solid iron. 2,625.36 2, 625. 36 2, 625. 36 — 08 2, 625. 28 2.629.8 — .18 Sectional iron 6, 247. 04 6,240.75 6,243.90 - 26 6, 243. 64 e,2,';4.4 - .01 Do. 3,681.64 3, 681. 64 3, 681. 64 - 15 3,681.49 3,687.9 Masonry. 5,498.50 5,492.52 5,495.51 - 14 5,495.37 5,504.9 .00 Solid iron. 3,555.48 3,558.65 3,557.06 - 08 3,556.98 3,563.1 .00 Do. 2, 461. 78 2.401.78 2,461.78 — 03 2,461.75 2,466,0 Crranite. 4,932.79 4,932.79 4,932.79 1 - 03 4, 932, 76 4, 941. 2 .00 Solid iron. 2,350.58 2, 350. .58 2,350.58 ' — 02 2, 350. ,56 2,354.6 .00 Do. 1, 768. 52 1,766.80 1,767.66 - 02 1, 767. 64 1,770.7 Marble. 226, 004. 79 225, 997. 79 226, 001. 29 —11 55 225,989.74 226, 379. 6 SECTION lO. METHODS USED FOR FIXING THE BOUNDARY IN THE ORIOrlNAX SURREY, 1819-1856. Astronomical determinations of the original survey. — In the first survey of the boundary line, in 1849-1856, there were established twelve stations for latitude and azimuth between the Rio Grande near El Paso and the Pacific near San Diego, and six of these — Paso del Norte, Oarrizalillo Springs, Nogales, Quitobaquita, Yuma, and Camp Eiley — were longitude stations. The results for longitude were obtained by observations of the transit of the moon and moon- culminating stars with telescopes of as large size as are usually used in field observations. 40 UNITED STATES AND MEXICAN ROUND AKY. In all cases where it was uecessary to disclose the results on the spot — as at those stations at the extremities of the azimuth lines, and at stations such as the one hundred and eleventh meridian of longitude, which formed turning- points in the boundary — the longitude was deduced from computations based on the data atibrded by the Greenwich Ephemeris before receiving corresponding observations. Owing to the fact that the final values of these longitudes when computed, using correspond- ing observations at Greenwich and other observatories, diflered from that first obtained by the predicted place of the moon as much as nineteen seconds of time, the difference of longitude between stations computed from different data was also affected by a considerable error. THE METHOD OF BUNNINO THE LINES ON THE GROUND. The parallel of 31° 17', the meridian section, and parallel Hl° 20'. — The initial point of parallel 31° 47' was determined by observations made by both sections of the original commission, and it was ascertained that the difference between the determinations of the parallel of 31° 47' made by the two sections was 0.84". It was mutually agreed to take the mean of the two results, and the point was ascertained and marked in the presence of both commissioners as the point where the parallel 31° 47' strikes the river; that is to say, the point where the boundary under the treaty of Decem- ber 30, 1853, leaves the river to run westward. A tangent to the parallel 31° 47' was laid oft" and prolonged westward, and Monuments Nos. 2 and 3 were set by offsets from the same, using the Bessel spheroid to compute said offsets. An astronomical station was then established at Carrizalillo Spring, the water nearest to the end of the required 100 miles, and its latitude and longitude determined. "A monnment was then established on the road due south of the observatory, and the parallel extended in both directions — east, until it met, in the sand hills, the line produced from the Rio liravo; west, it was extended to the end of the 100 miles, and the parallel was obtained by measuring offsets from the tangent." (P, 30, Emory's report.) In regard to the determination of the length of the line along parallel 31° 47', the result can not now be verified from the records. According to agreement of both sections, stated in Major Emory's reportof the boundary, " the 100 miles was obtained by combining the observed longitude at Oarrizalillo and the distance actually measured. (P. 30, Emory's report.) Later, the Mexican section made a new survey of the parallel 31° 47', starting a tangent at Oarrizalillo and extending it in both directions, east and west, and, not finding the monuments numbered G, 5, and 4 by Emory, they constructed four new ones. Two of these were near the locations of Nos.G and 5 (Emory), but the other two were erected instead of Monument 4 (Emory). This explains the discordance in the numbers on the United States and Mexican maps; the former showing eight monuments on parallel 31° 47', and the latter nine. For the pui-pose of measuring the distance between the monuments, a triangulation was made by Sehores Molina and Oontreras, extending the chain of triangles executed by Sefiores Fernandez Leal and Herrera along the meridian section to Monument No. 4 (Mexican) only; consequently, the distance between Nos. 3 and 4 (Mexican) was never measured by either section of the original commission, and the whole distance from the initial monument on the liio Grande to Monument No. 9, at the extremity of the line on parallel 31° 47', was never directly measured. This is not surprising when the difficiulties are considered under which that survey was conducted — the principal being the hostility of the Indians and the lack of water and other supplies in this desert region. UNITED STATES AND MEXICAN BOUNDARY. 41 The distances as shown by the United States and Mexican maps, coujparcd with the measured distances made by the present commission, are shown in the following tables: Comparison of Distances uetween Monuments, as Obtained from the Data Puxilisiied by the Commission OK lSt9-1856 with those Obtained by the Present Commission. Comparative distances on parallel 31° 47'. Monuments. Distances, 1849-1856. Difference from— United States. Mexican.! 1^92. United States. Mexican. I. (IE.) toll. (2E.) Meters. 697 Meiers. 713 4,278 56,745 19, 971 21,500 13. 192 21, 628 Meters. 713 54, 932 20,007 21,530 13, 214 21,656 Meters. + 16 Meters. - 8 —1, 813 + 36 + 22 + 50 —1,747 II (2E ) to III (3E ) 4,217 III (3E ) to IT V to VI (5E ) VI. (5B.) toTII.(6E.) VII.(6E.)toVIII.(7E.) 12, G47 21, 971 22. 627 98, 499 + 567 — 315 + 243 —2, 030 3E to5E 98 216 1 96 469 Meters. (1) Length of line according to United States maps, 1849-1856 160, 658 (2) Length of line according to Mexican maps, 1849-1856 - 160,847 (3) Length of line according to present conimissiou 159, 193 Difference between (1) and (3) —1,465 Difference between (2) and (3) - — 1,654 Meridian section. Meters. (1) Length of line according to United States maps, 1849-1856 49, 927 (2) Length of line according to Mexican triangulation, 1S55 49, 881 (3) Length of line according to commission, 1892 49, 928 Difference between (1) and (3) — 1 Difference between (2) and (3) —47 PARALLEL 31° 20'. A tangent to parallel 31° 20' was started from Espia and carried to Ojo del Perro. From Ojo del Perro a new tangent was run in both directions; east to the meridian, which checked the one run west from Espia, and west to the San Luis Mountains. At San Luis Springs, about 30 miles west of the initial point of the boundary on parallel 31° 20', observations were again made for latitude and azimuth, and a new tangent was started in both directions; east to meet the one from Ojo del Perro, and west across the San Luis Valley and the Guadalupe Pass. The ne.xt astronomical station was established at San Bernardino Springs, and the third tangent produced east and west; east to check and connect with tangent No. 2, and west as far as the hills west of San Pedro liiv^er. The fourth astronomical station was on the Santa Cruz River, in latitude 31° 17' 5(i.33", and from here a point on the parallel of 31° 20' was obtained by direct measurement, and a tangent started in both directions. The next station was at Nogales, in latitude 31° 21' 00.48" and longitude 110° 51' 2.10" west of Greenwich. From observations at this observatory a fifth tangent was deduced, and extended by a separate party in both directions, running west until the one hundred and eleventh meridian of longitude was reached. Owing to the difficulties of the country the longitude was transferred by direct measurement and by triangulation. (See Emory's report, p. 31.) "The monuments erected on the line were of two classes: First, of dressed stone, laid without mortar; second, of round stones, undressed, forming simply mounds. 42 UNITED STATES AND MEXICAN BOUNDARY. "Of tbe lirst, one was erected at the point south of the Carrizalillo, another at the intersection of meridian 108^ 09' 41.85" and parallel 31° 20', one at San Luis Springs, two at San Bernardino, one at San Pedro, one north of Santa Cruz, one where the line crosses (second time) Santa Cruz River, one at Los Nognles, and one at intersection of 111° and 31° 20'. Many mounds of the second das.s were erected, alway.s at points where the line crosses a road or trail. Mr. Salazar stated that he had erected, of dressed stone, in a permanent and durable manner, a monument at the initial jtoint on the Kio Bravo, and two monuments west of that point." (See Emory's Eeport, p. 32.) The following are excerpts fiom the journal of the joint commission, meeting of June 24, ISofi, page 37 of the report: Senor Salazar stated that after ho separated from Jlr. Emory, on the 20th of August, l><55, he reviewed with his parties the different Hues of the boundary; that is to say, the i)arallel 31*^ 47', the meridian, and the parallel 31° 20', on which lines the llexicau commission executed the following work: From the point south of El Carrizalillo, on which was erected a monument, he observed minutely on Polaris to determine the prime vertical ou both sides, east and west. The prime vertical and the parallel 31"^ 47' were connected by a triangulation, on the east side with that which had becu made at the initial point and on the west "side with the intersection of meridian. By this triangulati«m five points to the east were fixed, at which points he caused to be erected mouuuients of stone, with mortar, because he found not one established by the United States commission in said direction. The monument at the road was reconstructed of stone, with mortar. Upon all of them was inscribed the abridged inscription agreed npon. This line was then marked with ten monuments. That at tlie west itid he caused to be erected of dressed stone, with mortar, and inscribed with the complete inscription agreed upon, similar to that which was erected at the initial jioiut on the Rio Bravo. Mr. Salazar stated that he observed at the south end of the meridian for latitude and longitude, his results ditlering very little frcmi those of the United States commission ; that from this point was carried north a triangulation which was connected at the north end with that made on the parallel 31° 47', and was used to determine the position of said end (m the par.allel and on the meridian; that these two extreme points were left where the United States commission established them ; that having found no monument between them, he caused one to be erected intermediate, in sight of the Ojo de los Mosquitos, of dressed stone laid in mortar, with the usual inscriptions; that the monument at the south end was erected of dressed stone and mortar, with inscriptions similar in all respects to those at the north end and at the initial i)oint. Ou the parallel 31° 20', besides the observations he made at the intersection, he observed for latitude at San Luis Springs, at San Bernardino, and San Pedro River. He found monuments at the two first-named points, but none at the last; that his observations proved that the points were on the parallel 31° 20', aud he caused monuments to be erected at these points with mortar, having the usual inscriptions upon them, and that ho thought it proper to erect a monument of the same kind in Guadalupe Pass. Mr. Emory stated his entire satisfaction with what had been done by Mr. Salazar, and gave his assent thereto, except with regard to the monument at San Pedro River. He desired to call in Mr. Weyss, who was with Mr. Von Hippel when the monument was erected on the San Pedro. His own recollection was, that a very substantial monument had been erected at the San Pedro by the United States commission. Mr. Weyss was brought before the commissioners, and stated that a monument of dressed stone, with the usual inscription, was erected on the p.arallel 31^ 20', three thonsaud eight hundred and twenty-five feet west of the San Pedro River. The maps aud views were exhibited showing the exact locality of this monument. Mr. Emory stated, if the Indians had destroyed that monument it was all very well; but if it was still standing, there might be some discrepancy, amounting, possibly, to 1 inch of arc, or 100 feet between the latitude of the monument erected by Mr. Salazar aud that erected under his orders. If so, it might hereafter, when the country was settled, produce confusion. Mr. Salazar stated, that in case both existed he would take the mimument erected by Mr. Von Hippel as the true boundary. Assented to by Major Emory. For a complete list of all the monmneuts of every description found, see table at end of this section. The monument erected by Major Emory on the west side of the San Pedro Eiver, and that erected by Senor Salazar on the east, were both found in 1892, aud their latitudes, by astronomical observations, were as follows: Senor Salazar's monnment, 31° 19' 35" (United States); Major Emory's monument, 31° 20' 3.02" (Mexican), and the latter was used to retrace aud mark the line in 1893. UNITKD STATES AND MEXICAN BOUNDARY. 43 Comparative distances on parallel St^ 20'. Monuments. Distances, 1849-1856. Bist^^^ces, Diflereuco from— United States. Mexican. United Mexican. XI (lOE) Meters. Meters. Meters. Meters. Meters. 44, 390 5,885 4,8-5 4,404 20,156 18, 127 17,085 67, 729 23, 710 4,192 8, 082 24, 623 8,686 12,916 44,358 5,861 4,935 20,192 18, 087 17 002 46, 002 6,176 5,405 4,809 21,374 16, 991 IS ii\n +1,612 + 291 -1- 530 + 405 + 1,218 —1, 136 -1,325 +1,238 +5, 055 + 1.644 + 315 + 470 + 478 +1,182 —1, 090 -1, 242 4 1,521 +5,148 + 277 + 750 — 767 — 683 xvn (16E) XX (19E) 67.446 J 68,967 23,617 28,765 XXII CIE) XXIV (23E) 8,157 8,907 + 825 24,473 23,706 - 917 9,611 8,948 : + 262 12 893 12 fiSS 25R XXVIII (''7E) Meters. (1) Length of line according to United States maps, 1819-1856 264,860 (2) Length of line according to Mexican maps, 1849-18.56 265, 142 (3) Length of jine according to present commission 272, 954 Difference between (1) and (3) -|-8, 094 Difference between (2) and (3) +7,812 The line from 111° longitude and .31° 20' Intitude to a point in the Colorado River, 30 miles heloio the junction of the Gila and Colorado. — By agreement between the two commissioners the western end of this line was located in the Colorado Eiver, 20 miles below the junction of the Gila and Colorado. No monument could be placed here, but in the direction of the line, 4,135,74 meters from the initial point. Monument No. II, of iron, was erected. Tlie position of this monument is given as latitude 32° 29' 1.48", longitude 114° 46' 14.43", and the azimuth of the boundary line at this point as 71° 19' 23.18" southeast to the monument at the junction of 31° 20' with the one hundred and eleventh meridian, as determined by the original commission. As this longitude was found by the pre.sent commission to be 111° 4' 34.45" and the longitude of Monument II, 114° 46' 48.04", the computed azimuth of the line became 289° 1' 14.96"=70o 58' 45.04" southeast, a difference of 20' 38". The length computed by the original commission was 382,844.87 meters -4,135.74 meters =378,709.13 meters. The computed length in 1893 was 372,887.3, a differ- ence of 5,821.8 meters. After running the line for a short distance to the eastward the work was given up for want of water, and it was agreed that both parties cease work at the west end and proceed to the east end by the road along the Gila, the only available one at this season of the year, there to fix the point of intersection of the parallel of 31° 20' with the 111th meridian, as determined by the observed longitude of Nogales carried westward by triangulation and direct measurement. lu the latter part of August the instrument was placed in position and the azimuth (computed) of the new line (69° 19' 45.9" northwest) laid off, and the line was run by both United States and Mexican parties conjointly from peak to peak, marking these points by Monuments XIX, XTIII, XYII, XVI, XV, XIV, XIII, XII, XI, X, and IX. Monument IX stands on the Sierra de Sonoyta 14.5 miles from No. X, and about IJ miles north from the village of Sonoyta. The distance between monuments was determined by a rough triangulation consisting of intersections on prominent peaks, north and south of the line, measuring only the angles at the location of the different monuments and concludiug all others. 44 miTED STATES AND MEXICAN BOUNDARY. Ou the plain near Sonoyta a base was measured by the Mexican section and a connection made from this measured base with the line— Monuments IX to X — by four triangles with con- cluded angles, and from this line the distances between the other monuments to the eastward were computed. This triangulatlon was also carried westward to include Monuments YII and VIII, near the astrononucal station at Quitobaquita, and afterwards still farther west to Monu- ments VI and V. The distances obtained by triaugulation from the measured base were then adjusted to sum up equal to the distance from Monument VII to the eastern extremity of the line, as obtained by computing this length from the astronomical positions of the two ends, viz, Quitobaiiuita and the 111th meridian. The distance between Monnments VII and V, obtained from the triangulatlon from the measured base, was used uncorrected for the final adopted distance of Monument V from j\Ionu- ment VIl. The distance from Monument 1 1 to Monument IV was assumed to be that determined by the triangulatlon at Yuma. The sum of these distances, viz, Monument VII to V plus Monument II to IV, was then subtracted from the whole distance. Monument VII to Monument II, as obtained from the longitudes of Monuments II and VII, for the distance between Monuments V and IV. In 1893 neither Monument IV, on the Tinajas, nor Monument V, on the Tules, nor Monument III, on the desert, said to have been built a short distance east of Monument II, could be found, nor could anyone be found who had ever seen or heard of these monuments. The line of 1893 was therefore run by the United States section from Monument II to Monument VI, and afterwards carried eastward, from monument to monument, to its eastern extremity, now Monument No. 127. The Mexican section ran this line from the eastern end, and the location of points on the line between existing monuments where new monuments were erected in 1893-94 was determined by the data furnished by both surveys. The dilferences in the distances between the original monuments on this line, as determined by the fli-st survey in 1855, and those obtained by actual measurement in 1893, reduced to sea level and adjusted to sum up equal to the astronomical distance from Monument No. 204, on the Colorado River, to Monument No. 127, at the end of the line on parallel 31° 20', are given in the following table. The measured distance of stadia and triangulatiou reduced to sea level is 372,971.02 meters; the computed distance on broken line from the astronomical positions of the two ends, 372,887.3 meters; the difference being 83.8 meters, or 1 in 4,550. 'om2>araiive distances on Sonora line. Mouuiuent. Distance determined In— Difference. 1849-1853. 1892-1894. Meters. Meters. Meters. \1 175, 026 162,894 - 12, 132 I\ 31, 379 31,314 — 65 5 23. 105 23,415 + 10 5 11 6,974 7,273 + 239 SIII 44, 699 46,562 + 1,863 SIV 18,986 19, 875 + 8S9 sv 26, 494 27,565 -t- 1,071 5 VI . 14, 593 14, 746 + 154 SMI 3,519 4,230 + 717 5 VIII 27 963 28, 974 + 1,012 3 IX 5,262 5,638 + 376 P irallU -il" 2a 409 394 — 15 Metei Distance from Monument II to e\treiiut\ of lino on parallel il'J 20', according to United States maps, 1849-1856 378,' Distance according to present commission 372, 1 Dilfereuce 5,1 UNITED STATES AND MEXICAN BOUNDAEY. 45 Meastirements of the 20 miles from junction of the Gila and Colorado to initial point in Colo- rado. — We have by report of original commission the data to reduce to the junction of the Gila and Colorado, as then existing, the point selected by the commission in 1849 on the azimuth line joining the junction of the Gila and Colorado rivers with Jlonumeut I, on the Pacific. By the measurements then made this point was found to be 73.5 feet south and 1,070 feet west of the junction. It was originally marked by an iron monument, subsequently transferred to a point near the Colorado River on tlie new ArizonaSonora line, and called Monument II. If we admit that the post found in 1893 marks the point established in 1849, as all the testimony obtainable from old residents of Yuma seems to prove, we have the latitude and longitude of the junction of the Gila and Colorado 0.73" north and 12.53" east of the boundary post of 1893. Its latitude will therefore be 32° 43' 30.27" and longitude 114o 36' 44.08." Computing from Monument II to initial point in the Colorado Eiver by data of the original commission, giving the distance from Monument II to initial point as 4,135.71 meters and azimuth 108° 40' 36.82", we have latitude of initial point = 32° 29' 43.97", h)ngitude = 114° 49' 18.71". The positions of both junction and initial point are here given as derived from the observed latitude and longitude in 1893 at Tuma, transferred by triangulation to boundary post and Monument II. Computing the distance and direction of line from initial point in the Colorado to junction of Gila and Colorado, from latitude and longitude given above, we get the distance 32,171.4 meters, or 15 meters less than 20 miles. Its azimuth is 217° 38' 53.06". The difference of latitude of the two points is, by original commission, 13' 47.85"; by present commission, 13' 46.30"; of longitude by original commission, 12' 34.78"; by present commission, 12' 34.63". THE CALIFORNIA LINE FROM THE INIl'IAL POINT ON THE PACIFIC TO THE JUNCTION OF THE GILA AND COLORADO RIVERS. Emory's report, page 5, says : At the various conferences of the joint commission, the modoof conducting the survey was discussed; and it was agreed to determine the line by astronomical methods, as the only mode by which we could do so correctly and within our means. On page 144 the report says: The following is the order in which are arranged the subjects eiul)raied in the determination of the line: 1. The longitude of Camp Riley, near the initial point. 2. The longitude of camp near the, junction of the Gila and Colorado. 3. The latitude of Camp Riley, near the initial point. 4. The latitude of camp near the junction of the Gila and Colorado. 5. Transfer of the latitude and longitude of Camp Riley, by triangulation, to the initial point. 6. Azimuth of straight line from initial point, on Pacific, to Junction of Gila and Colorado. The comijutatious are given on pages 162-166, and on page 165 we find — Latitude of initial point on the Pacific 32 31 5il.63 Latitude of junction of Gila and Coloriido 32 43 32. 2 Difference of longitude 2 32 24. 9 From our results for latitude and longitude in 1892 and 1893 we have — Latitude of initial point on the Pacific 32 32 1. 34 Latitude of junction of Gila and Colorado 32 43 30.27 Difterence of longitude 2 .30 47. 9 The difference in the results for difference of longitude by original commission in 1849 and present commission in 1892 = 1' 37". Resulting azimuth at initial point on the Pacifii- by original commission 264 12 2.95 Azimuth of line Monument I to Monument VI, 1893 264 10 50.33 The line was run by the original commission from both ends toward the desert, and Monuments I, II, and III were erected near the west end and Monuments VI, V, and IV near the east end. The space between Monuments III and IV (82 miles) was unmarked. UNITED STATES AND MEXICAN BOUNDARY. Compuratire distances on California line. Monuments. Distance, 1849. Y^^^_ 1 Mexican. Distance, 1893. Meters. Differenc e from— TJnitcd States. Mexican. Meters. Meters. Meters. Meters. IIT 19,247 1 19,810 145,823 144,109 2.831 2,783 57,418 1 54,931 20,600 132, 080 2,780 70. 918 + 1,353 —13, 743 — 51 + 13,500 + 790 — 3 + 15,987 V Meters. (1) Distance between Monuments I and VI, according to United States maps. 1849 225,319 (2) Distance according to Mexican maps, 1849 221,633 (3) Distance according to present commission 226, 380 Difference between (1) and (3) 1,061 Difference between (2) and (3) 4,797 The Uuited States distances shown in preceding tables, of parallels 31° 47', 31° 20', and the California line, were deduced graphically from the United States maps of the original survey. The distances on the Sonora line were copied from the report of Major Emory, and agree with those given iu the manuscript report of Senor Jimenez. The Mexican distances along parallel 31° 47' were obtained from the tiiangulation made iu 185") by Senores Contreras and Molina, with the exception of those between Monuments I, II, III, and IV, that were taken grai)hically from the ]\Iexican maps. The distances along parallel 31° 20' and California line were taken graphically from the same maps. The meridian section was obtained from the triaugulatiou made in 185.5 by Seiiores Fernandez Leal and Herrera. DIl-'FERENCES BETWEEN DETERMINATIONS OF LONGITUDE BY ORIGINAL COMMISSION AND THOSE OF THE PRESENT SURVEY. The following table gives the latitudes and longitudesof the principal points along the boundary, aud shows also the difference between the determinations of the original commission and those of 1892. Two of these longitude differences have a material bearing on the location of the boundary as regards the area of territory lost or gained by either country in consecjuence of errors iu the first sui'vey. According to the treaty of 1S53, the parallel of 31° 47' north latitude shall be the boundary from the initial point on the Eio Grande where the parallel crosses the river; " thence due west 100 miles; thence south to the parallel of 31^20' north latitude; thence along said parallel of 31° 20' to the lllth meridian of longitude west of (Greenwich; thence in a straight line to a point on the Colorado IJiver 20 Phiglish miles below the junction of the Gila and Colorado rivers; thence up the middle of said river Colorado until it intersects the present line between the United States and Mexico." The length of parallel 31^ 47' was made by the original commission, from the initial x)oint in the Rio Grande to Monument 40, to be 1° 41' 57.55" (see p. 190, Emoi-y's Eeport), which is equal on Clark's Spheroid to 100,953.9 meters. The present survey made the length of parallel between the channel of 1853 — distant 71.04 meters from Monument 1 — and Monument 40, 159,264.4 meters. The survey of 1892 showed the channel of the Rio Grande to be 172.06 meters east of Monument 1, so that the length of parallel 31° 47' in 1892 was 159,365.5 meters. One hundred miles on parallel 31° 47' equals 100,933 meters, so the parallel now is 1,567 meters short of 100 miles; and at the time of original survey the parallel was 1,068 meters short of 100 miles. Monument No. 127 was placed at the iutersectiou of parallel 31° 20' with the lllth meridian of longitude, as determined by the original commission. Our longitude of Monument No. 127, is 111° 4' 34.4", or 4' 34.4" too far west — equal to 7,254,2 meters, or 4.5 miles. UNITED STATES AND MEXICAN BOUNDARY. 47 Tlie difference of longitude between tlie boundary i)ost at Yuma, and Monument 1 on the Pacific, was 2° 32' 24.9", as determined by tlie original commission in 1849. (Page 165, Emory's Keport.) By determination of 1892 it was 2° 30' 47.9". The distance from the junction of the Gila and Colorado to Monument I on Pacific, is 2,534 meters less than that by the original commission. Comparison of latitudes and longitudes observed in 1S92~93 with those of the original survey in 1S49-1S56. Latitudes. Longitudes. 1892-93. 1 1849-1856. j 1892-93. 1849-1856. 31 46 59.70 60.00 I 108 12 29.67 108 l:i 24.05 31 20 1.79 0.00 1 108 3 29.07 | 108 13 24.05 31 19 59.30 60.00 111 4 34.45 HI 0.00 32 29 1.00 1.48 114 40 48.64 114 46 11.43 32 43 29.54 31.60 114 36 56.67 114 36 22.20 32 31 61.34 59.63 117 7 31. S9 117 .S 29.70 The differences in the results for longitude are due to imjiroved methods of observation and the use of the telegraph by the present commission. Original vwniimcnls. PARALLEL 31° 47'. No. of nioDument 1 on original survey. No.whon „??etut in 1892. Distance ap„t. Description of monuments when sun-ey was made. United k. States. 1^ xican 2liUs. 1 3 Cutstone; pyramidal form ; square base; inscriptions; fair preservation. Koughly dressed stone; pyramidal form ; square base; no inscriptions ; poor preservation. Kouglily dressed stone ; pyr.lmidaU'ornn square lias.-; no iusoriptioiis; good 2 3 0.4 2.6 11 34.3 preservation. Kough stones; mud mortar; pyramidal form; square l.ase; inscriptions; 15 12.4 tumbling to pieces. Do. 5 21 13.4 Do. 6 26 8.2 Do. 7 33 13.5 Do. 8 40 14.2 Cutstone; pyramidal form : square liaae: in.scriptimis : L'wrl imservatiou. i 99.0 MERIDIAN SECTION. 8 10 9 10 Jl 40 46 53 Cutstone; pyramidal form ; square base; inscriptions; good j.reservation. Hough stones; mad mortar; pyramidal form; square ba,se; inscriptions; ; poor preservation. ; Cut stone; pyramidal form; squarr base: inscriptions; .■xccllcut preserva- tion. 15.2 16.8 31.0 48 UNITED STATES AND MEXICAN BOUNDARY. Original monuments — Continued. PARALLEL 31<= 20'. No.when repaired or rebuilt iu 1892. Distance apart. Miles. 10 11 53 0.0 Cut stone; pyramidalforra ; square baso; iiisiriptimia: exnellentpi-eserration. 12 13 64 28.7 Mound of loose atones; circular base ; height 4 feet; no inscriptions. 13 14 65 3.9 Mound of loose stones; badly scattered; circular base; no inscriptions. [ U 15 60 3.4 Rough stones; mud mortar; pyramidal tbrui; square base; inscriptions; tumbling to pieces. 15 16 07 3,0 Mound loose stones ; baiUy scattered ; square base ; no inscriptions. 16 17 73 13.4 Loose stones ; pyramidal form ; square base ; inscriptions ; tumbling to pieces. 10.5 Loose stones; pyramidal form; square base; no inscriptions; fumbling to pieces. 18 19 77 .1 Loose atones ; pyramidal form ; square base ; inscriptions ; tumbling to pieces. 19 20 82 9.9 Pulled down ; apparently pile of loose stones ; round base ; no inscriptions. 20 21 98 43.1 Loose stones; pyramidal form ; square base; no inscriptions; tumbling to 21 «o 106 18.0 Loose stones; almost entirely demolished; no inscriptions. 23 23 108 2.8 Loose stones; pyramidal form; sqmvrobase; no inscriptions; tumbling to pieces. 23 24 111 5,5 Do. 24 25 25 26 No trace remaining. Loose stones; pyramid;il form; square b;.se; no ins.iiiitiori.s ; tumbling to 118 14.8 pieces. 26 27 122 5.6 Loose stones; pvnuuid;il form ; siiuaru b;ise ; inscriptions; tumbling to pieces. 27 127 7.9 DO. 170.6 LINE J''ROM WEST END PARALLEL SI" 20' TO COLORADO RIVER. No. of monument on original survey. No. when repaired or rebuilt iu 1893-94. Distance apart. Description of monuments when survey was m;ide- mies. xis- 128 0.3 Mound loose atones ; round base ; 3 feet high ; no inscriptions. xnii 129 3.5 Loose stones; squaiebase; 25 feet high; no inscriptions. XVII 136 J8.1 Mound loose stones; round base; 2Jfeethigh; no inscriptions. SVI 137 2.6 Do. XV 141 9.2 XIV 146 17.2 Mound loo.se stones; round base; 5 feet high; no inscriptions. XIII 150 12,4 Mound loose stones; round base; 4 feet high; no inscriptions. xir 160 29,1 Mound broken lava; round base; 3 feet high; no inscriptions. X 162 4.5 Mound broken lava; square base; ifeethigh; no inscriptions. IX 168 14.7 Mound loose stones ; round baae; 4 feet high; no inscriptions. VIII VII VI No trace remaining. Do. Mound loose stones; round base; 3 feet high ; no inscriptions. 175 19.6 No trace remaining; probably never erected. Do. No trace remaining. IV III II 204 101.8 undermined. J No trace remaining. Initial 1 Pointed. 2.7 River. 1 235.7 * It "was decided by tlie engineers in chief of the two sections that this monument was not suflSciently authentic, and it was not accepted. Mouument 128, however, was erected ou the lino joining Konument^ 127 and 129, and but 1.81 meters south of the center of this mound. UNITKD STATES^ AND MEXICAN ISOUNUAKY. 49 Oni/inal i/i«»««ie>i/s— Ccmtinued. LINK FEOM THK (JOLOKAUO KIVEK To THK PACIFIC OCEAN. ' Xo. of Xo. whuMi I mouuinent repaired Disfuuce Description ..f nwinumeiits wlieu survey w:,,s maile. oil original or rebuilt apart, survey. in 1894. 0. 6 I Entirely i i-t. 8 ' Ca.st iron eniulisiietl; Itasc was iiI:K-e!•' UNITED STATES SECTION. By agreement between the eugiueers iu chief of the two .sections of the joint couiuiission. each section was to map the topographic features of a belt 2i miles in width on its own side of the boundary line, in such detail as would be necessary to plot the locations on field maps of a scale of 1 4- 30,000. To do this the measured distances along the boundary were used as bases, and stadia lines were run from the boundary, in a general northerly direction, to near the outer limit of the topographic belt, turning near this limit so as to cover most conveniently the principal topographic features in the vicinity, and then returning and closing on a located point on the boundary line. From these closed lines " spur lines" were run as needed, and from botli the closed and spur lines numerous secondary sights, giving azimuth, distance, and vertical angle, were taken. On both the closed and spur lines backsights and foresights were always taken, and at each of these sights the a/iniuth, the distance and vertical angle were read. The maximum error in distance allowed on closing was one three-hundredth, and in elevation one decimeter per kilometer per degree of average vertical angle of the courses of the Hue. In some cases locations were made by intersections, and occasionally the topogra[>hy was "filled in'' from located points by anl of tlie prismatic comjjass, hand level, and sketching. Between the Pozo Verde Mountains and the Colorado Elver, a distance of more than ;!23 kilometers, the region bordering the boundary line is ditticult of access, remote from railroads, is practically uninhabited, and is a true desert, containing but five badly spaced permanent watering places in the entire distance. Owing to these causes, and in order to expedite the work in this inhospitable region, it was decided that between the west end of parallel 31° 20' and the Colorado Eiver a topographic belt, 1 kilometer iu width, adjacent to the boundary line would be surveyed and plotted in the usual manner, but that the remainder of the L'i mile belt of topography would be taken by placing (lags on all of the prominent peaks, ridges, and other natural objects, to be located by the transit man engaged in measuring the boundary line. Another transit man would then occupy these positions and from them locate all flags in .sight. Other important topographical features were then to be located, either by stadia or by resection, and contoured sketches of the immediate vicinity made. Datum points for elevations were given by a line of levels carried along the boundary from the Kio Grande to the Pacific, and connected at VA Paso, Tex., and Yuma, Ariz., with bench marks of the Southern Pacific Railway and at San Diego. Cal., with a bench mark established by the United States Coast and Geodetic Survey. S. Doc. 247 4 50 UNITED STATES AND MEXICAN BOUNDARY. The datum ])hiiK', was that of mean sea level of San Diego Bay, California. (treat care was taken in running the line of levels. The rods were held on iron pins driven firmly in the ground. Equal foresights and backsights were taken, and at each setting of the instrument both of these sights were read until two values of each were obtaiued which did not differ more than 1 millimeter, the rod being undamped and reset after each reading. The mean of the two values thus obtained was taken as the true reading. Most of the topographic notes were reduced in the field by the observers who took tlieui, and about half of the field sheets were plotted there; tlie rest were plotted in the ofBce either by the assistant engineers in charge of topographic work in the particular region or by an assistant engineer i)ersonally familiar Mith it. TOPOGRAPHY OF TIIK MEXICAN .SECTION. From the initial monument on the KioCrraude to Monument 111 (XXIV) the method employed was to determine, by intersections from different points on the tangents, the most prominent jtoiuts of the ground, the lines joining these points then constituting bases from which other points were fixed by intersections. At some of these points conveniently selected, sketches of the ground were made to complete the configuration. In some places polygons were run with bearings and distances, having as bases points on the tangents or referred to said tangents, meas- uring the distances with tape or stadia. The heights were determined by vertical angles. From Monument 111 to 253 on the Pacific Ocean the method of detail employed was a series of polygons, run by bearings and distances by means of a field compass and odometer on wheels run by hand, said polygons having as a base two consecutive monuments of the boundary. From several points of these polygons sights were taken to the most prominent points of the ground to fix them by intersections, and a sketch of the ground was carried of 1 kilometer in width on each side of the line of the polygon. The heiglits were determined Avith aneroids and vertical angles. Each polygon was run so that it would take in the most important details of tiie ground, and was selected to obtain the best points of view for the sketches. At the Colorado River a special survey was made by a chain of triangles along its banks and 180 vertices were locatetl exactly on the banks of the river. Of these vertices one-half were on the American side and the other half on the ^Mexican side. The angles of the triangulation were measured with two theodolites reading to J minute, repeating each angle twice in both positions of the instrument. The first base for the triangulation was measured on the line ont from Monument 206 to Monument 207, and its azimuth obtaiued from the line of said monuments. The triangulation was carried on to Monument 205. Four bases of verification were measured at nbout every 45 triangles, and every section of the chain was computed from its own measured base. The islands were surveyed by polygons lying oii the vertices, measuring the distances with metric tape, when the polygons were small, or with odometers upon handwheels, when they were large. By the same method the main estuaries were surveyed and other polygons were run in the valley of the river so as to take in the detail of the Mexican side and make sure that no detail was hidden by the vegetation. The final results of the triangulation were computed with the ditterences of geographical coordinates, between Monuments 205 and 207, and were compared with those obtained for the same points by the geodetical work of the commission. The following differences were found; l)iHeren..5 and 25."»-2r)(>, and to modify the tables to conform to the new position of Monument 255, as relocated by the two engineers in chief after its destruction in January, 1895. J. W. Bai;low, jACono Blanco, Colonel of Eni/iiiirrn, ('i>miiiiKsi<»tcr. Inyo, en Jefe, de la Hevcion Mcx. 1). D. Gaillakd, Valentin Qama, Firnt Lieut, of Knijhueni. Adjuiito Astrouonio. A. T. MdSMA.N, GriLLKKill) 15. Y PlTGA, As.si.stdiitj Coa t (iikI (Iciidclic iSnrrc.i/. Adjiinto Aatrouomo. At a meeting of the commission held January 10, 181U!, a general form lor tlie joint report was agreed upon, which has been substantially followed in writing the re])ort. At a meeting of the International Boundary Commission, between tlie United States and Mexico, held in Washington, 1). C, on January 23, 189G, all the members being present, it was agreed, subject to tlie approval of the two Governments, to have the 20 sheets of the joint map of the survey of the United States and Mexican boundary, from the I»io Grande to the Pacific, engraved upon copper, tlie expense, approximately $8,000, United States currency, to be equally divided. Jacoiso I'.lanco, J. W. Baulow, Ingo. en Jefe, de In Seccion Met: Colonel of Engineers, U. 8. A. Valentin Gama, D. D. Gaillard, Adjiinto Astronomo. Captain of Engineers, U.S.A. GUILLEKMO B. Y PTJGA, A, T. MOSMAN, Adjiinto Astronomo. Assistant, Coast and Geodetic Siirvei/. Washington, D. G., February 34, 1896. At a meeting of the joint commission held this day, at which were present all of the members, it was agreed that the part of the joint report relating to astronomical observations (latitude, longitude, and azimuth) should consist of: First. A table containing the final results of the determinations made by the Mexican section of tlie commission with their probable errors; the method of observations; the number of nights on which observations were taken; the number of observations, and the name of the observer. Second. A similar table, giving the corresponding results obtained by the American section of the commission. Third. A table of means and flii;il values adopted by tlie International Gomniission. Jacobo Blanco, j. w. Barlow, Ingo. en Jefe, de la Sercion Me,v. Colonel of Engineers , Valentin Gama, Engineer in Chief of the American Section. Adjunto Astronomo. 1). D. Gaillard, Guillermo B. y Puga, Captain of Engineers, U.S.A. Adjunto Astronomo. A. T. Mosman, Assistant, U. S. Coast and Geodetic Survey. UNITED STATES AND MEXICAN i;OUNDARY. 53 st:ctjon 13. construction of the jmaps of the boundary. The field maps of the topography were mule, as described iu section 11, on a scale of 1-^30,000, tiie part on the north of the bouuda'y of a width of 2| miles by the United States section, and the part south, of the same width, by the Mexican section; the width of the entire belt plotted being 5 miles. At a meeting of the joint commission on October 23, 1895 (see section 12), it was agreed that the scale of the final maps shall be 1-^60,000; that the contour intervals shall be 20 meters; that the projection used shall be polyconic; that the intervals between meridians and i)arallels shall be five minutes of arc, and that the center meridians shall be perpendicular to the lower edges of the sheets, which shall be 1 meter in length. As a basis for plotting tlie maps the horizontal distances between monuments shall be used. Elevations will be determined by the level line run by the United States section. Before beginning the maps it was agreed tliat a mean parallel of latitude should be adopted, which should be the mean of all the observed latitudes along the boundary, and that the horizontal distances between monuments given in the tables of section 9, together witli the mean latitude, should govern their location. The topography of the 2^ miles to the north of the line was then drawn in pencil, reduced from the field maps of the United States section, by the United States draftsmen. The topography of the 2.J miles south of the line was also drawn in pencil, reduced from the field maps of the Mexican section, by the Mexican draftsinen. The maps in pencil were then carefully compared before inking. The land boundary between the Rio (irande and the Pacific was contained in 18 sheets. A sheet (numbered 19) was then drawn for the Colorado River section. As the river and the eastern side had been surveyed by the United States section in March, 1S93, and the river and the western side by the Mexican section in February and lAIarch, 1891, the two representations of the river do not correspond,* so both are shown on sheet No. 19 in difterent colors. In the following table column i shows the observed latitudes at nineteen stations along the boundary called A, and column 3 the mean geodetic latitudes resulting called G; column 5 shows the difference G — A, or the derived "station errors" in latitude of all these nineteen stations. Mean geodetic latitudes, reduced to mean of United States and Mexican obseried latitudes on whole tin Moiinmenta. Mean geodetic S = G. Observed S-=A. G — A. 1 Olil No. Xe«- No. J 1 31 46 61.35 31 46 59.40 +1. 95 On EiO Grande. 60.95 60.88 + .07 Mex. Station No. 2, oude.-ert. 5 15 60.54 60.34 + .20 Near Wragg's Kanch. a 21 60.62 58.85 + 1.77 Near Columbus. 7 26 60.56 .58.08 +2.48 Near Carizalillo Springs. 9 11 40 31 60.59 19 59.48 31 59.70 19 61.79 + .89 -2.31 Upper corner. Lower corner. 1 13 U 59.27 59.29 57.94 62.60 +1.33 U.S.Sta.No.6,nearWliilewater. -3.21 Mexican Statioi. No. 6. 16 19 67 77 55.52 61.51 60.85 62.89 56.86 58.99 59.65 60.07 —1. 34 ! Near Lang's Rancli. +2.52 San Bernardino. +1.20 Max. Station No. 7, Niggerhead. -3.18 U.S.Sta. No. 9, Dutch Charleys. 21 98 62.13 63.02 -.89 ' SauPedru. 2i 111 57.83 57.58 + .25 Lanoria. 11 122 204 32 57.03 29 2. 16 32 60.75 29 1.00 —3. 73 Nogales. +1. 10 East bank Colorado Kiver. 32 43 35.85 ■ 32 43 34.69 +1. 16 U. S. Station No. 13, Yuma. I 258 32 32 1.01 32 32 1.34 -0.33 On Paciflo coast. * The difference in the two representations of the river arises from the fact that the bed of the river changed betv United States survey in 1893 and that of the Mexican survey in 1894. UNITED STATES AND MEXICAN BOUNDARY. Meau lalitiidea and longiliides of monnmeiUs on pu^-iilhd Sl^ 47 Mean la itn.le. Longitude. 'No. Mean hi itmle. Longitude. Old. New. , V „ ' / ^ 31 40 01.35 106 31 39.03 6 21 31 40 60.62 107 35 55.08 fil. 35 32 6.15 22 60.01 37 10,98 CI. 35 34 48.40 23 00. 00 38 12. 30 fil. 23 39 36.60 24 6". 58 41 1.27 01.11 44 23.51' 25 00.57 43 26.71 00.98 49 25.01 7 20 00.50 44 17.32 no, 8.-I 54 19.01; 27 00. 50 46 15.15 00.72 59 18. 9V 28 00.50 48 29.51 CO. 70 107 12.31 29 60. 57 50 49.55 00.59 4 39.40 30 60. 58 53 33.44 60. 4e 9 36.31 31 60.58 55 44.04 60.48 12 50.38 32 60.58 57 10.87 60.51 17 13.71 8 33 GO. 58 58 0.44 60.53 20 11.73 34 00. 58 108 u 38. 69 60.54 22 10.77 35 60. .^.9 :i 31.50 r,o. .^5 23 19. R8 30 CO. 59 5 52. 55 oil, .'•.7 -O .-.. -ri 37 CO. 59 7 40.81 Mean liiiitudes and longitudes of monument Longitude. Old. New. s on parallel 31 Mean latilude. SO'. X Old. New. Mean lalitn.le. Longitude. 11 53 31 19 59.48 108 12 29.67 91 31 19 61.95 109 ,52 24.96 54 59.47 15 0.28 92 01.98 50 0. 35 55 59.40 19 16.34 93 C2. 02 58 49.19 50 59.46 20 37.23 94 02.01 110 54.37 57 59.45 22 54.07 95 02.06 3 5.84 58 59.44 26 26.30 90 02.08 5 2.13 59 59.44 27 45.48 97 02.11 7 19.22 00 59.43 31 50.50 21 98 02.13 9 25.78 01 59. 42 35 28.98 99 61.35 12 34.00 62 59.41 36 51.84 100 00.59 15 38.45 63 59.40 38 57.98 101 00.52 15 .55.19 13 64 59.39 41 29.75 102 60.25 17 0. 02 14 05 55.16 45 23.40 103 59.44 20 14.13 15 00 55.37 48 47.84 104 .59. 08 21 43.13 10 67 .55.52 51 49.75 105 58.05 23 28.25 68 55.58 53 55.10 22 106 57.63 27 33.80 69 55.07 57 3. 65 107 57.51 29 24.64 70 55.73 59 9. 41 23 108 57.45 30 22.43 71 55.85 109 2 59.82 109 57.60 32 36.99 72 55.87 3 42.46 110 57.75 34 42.90 17 73 55.92 5 18.23 24 111 57.83 35 59.32 74 57,17 7 41.72 112 58.15 37 40.68 75 59. 04 11 10.56 113 58.88 41 31.98 70 0(1. 37 13 49.17 114 59.11 42 47.35 19 77 61.51 10 0.95 115 59.48 44 42.58 78 61.53 17 15.36 116 50.94 47 8.71 79 01.58 21 1.88 117 CO. 43 49 45.47 80 01.02 23 58.88 26 118 60.05 50 56.03 81 01.63 24 49.13 119 58.57 54 10.58 20 82 01.65 25 57.08 120 57. 57 55 44.08 83 01.00 27 7. 84 57.13 50 24.78 84 01.70 30 57.13 27 122 57.03 56 34.49 85 01.72 33 27.82 123 50.81 57 47.12 80 61.75 36 15.94 124 56.46 59 43.02 87 01.80 40 15.26 125 50.11 HI 1 39.05 88 61.84 44 28.18 126 55.00 4 25.68 89 61.88 40 39.20 28 127 55.58 4 34. 45 -Ji 61.91 49 10.17 UNITED STATES AND MEXICAN BOUNnARY. Mean luliUidcs, loiii/itudes, and azinuilim alomj tin 55 Colorado Monnnients. Mean latitude. Longitude. Azimuths. To monu- inrat. Distance. . Jfelert:. Old No. ^7 Back. ^ -. ^ u , 27 127 31 19 55.5 111 4 34.4 110 40 12 290 38 22 129 6,031.5 XVIII 129 31 21 4.6 111 8 7.8 110 34 51 290 25 59 136 28,973.8 XVII 136 31 26 34.2 111 25 15.1 110 26 12 290 24 53 137 4,235.7 XVI 137 31 27 22.2 HI 27 45.4 no 21 20 290 19 53 141 14,746.5 XV 141 31 30 8.9 111 30 29.1 no 20 49 290 12 17 140 27,505.0 XIV 146 31 35 19.1 111 52 49.4 110 14 37 2911 8 20 150 19,875.1 xm 150 31 39 1.8 112 4 37.2 no 5 18 2S9 50 44 160 46,562.1 XII 160 31 47 38.1 112 32 19.5 109 51 13 2K9 48 50 102 7,273.3 X 162 31 48 58.2 112 .30 39.0 109 48 22 289 41 110 108 23,415.2 IX 168 31 53 15.0 112 50 37.9 109 39 14 289 29 20 175 31, 314. VI 175 31 58 55.6 113 9 21.2 110 24 22 289 32 23 204 162,894.5 II 204 32 29 2.2 114 40 48.6 108 40 37 288 39 38 205 3,000.0 205 32 29 33.4 114 48 37.5 127 375,887.3 Mean hitilndcs, lomjitudts, and azimnths along the California live from Monument Xo. 30G to Monument No.SoSon Paciji: Monuments. Mean latimdc. Longitude. Azim Forward. uths. Ba k. To Old No. r o , ,r r . .. o , „ , „ Meters. 206 32 43 5.0 114 43 23.2 85 ^ 31 9 265 30 52 207 809.4 VI 207 32 43 3.0 114 43 54.3 85 30 52 260 43 220 70, 109. V 220 32 39 57.0 115 28 36.7 85 i 17 205 1 20 221 2,780.4 IV 221 32 39 49.2 115 30 23.0 85 11 33 264 15 15 252 132, 080. 3 HI 252 32 33 8.0 116 54 20.4 84 17 57 264 14 51 254 9, 068. 254 32 32 38.0 117 12.2 84 14 43 204 13 32 255 2,466.0 255 32 32 30.6 117 1 46.2 84 14 34 204 12 53 256 4, 941. 2 ' 256 258 32 32 32 14.4 31 111 117 4 .-.4.6 84 12 57 264 n 32 258 206 4,125.3 226, 379. 6 The foregoiug report is hereby attested by tlie signatures of all the mt'iiibers of the Interna- tional l>ouiidary Commission. Done at the office of the commission in the city of Washington, 1). V., this the 14th day of Augnst, 1896. Jacobo Blanco , Iiujeniero en Jefe de la Secciihi Me.vicana. Valentin Gama, Adjtmto Astrimomo. GUILLERMO B. Y PlTGA, Adjunto Astro iiomo. .). W. Barlow, Colonel of Engineers, Enf/ineer in Chief of the American Section. A. T. MOSMAN, Assistant, United States Coast and Geodetic Survey. D. D. Gaillard, Captain of Engineers, I'. N. A. At a meeting of the International Boundary Commission held at the office of the commission^ in Washington, D. C, August 14, 1896, present all members, the following resolutions were unanimously adopted : 1. That the full report of the Joint commission prescribed in Article V of the convention of July -29, 1882, shall consist of the accompanying manuscripts, written in the English and Spanish languages, both in duplicate, compri-sing, in the English copies, 100 pages, and in the Spanish copies, 94 pages, of type-written test, includiug tables. These copies have this day been signed by all the members of the commission, and one copy in each language will be retained by each 56 UNITED STATES AND MEXICAN BOUNDARY. section of the cominissiou for transmittal to the proper department of its government; also, copies, each iu duplicate, one for each section of the commission, of the joint map of the survey, comprising nineteen engraved sheets, on a scale of 1 -4- 00,000, covering the boundary from the Rio Grande to the Pacific Ocean aud showing the topography of a belt of territory 5 miles wide. 2. The report and map above specified are now complete and have been dnly attested by the signatures of all the members of the commission. 3. In addition to these will soon be completed a set of illustrations, 300 in number, prepared from photographs taken iu the field, showing views of the 2r>8 monuments marking the boundary and special characteristic scenes. 4. It is further agreed that the engraved plates and electrotypes of the map, twenty of each, shall be equally divided between the two sections of the cominissiou. These plates and electrotypes ^ 47' 176 Monuments Nos. 8. 9, and 10, on the meridian section 176 Monuments Nos. 12 to 27, on parallell 31° 20' 176-177 Monument No. 26, at Nogales, Ariz 177 Letter from commission to Secretary of State on proposed reservation alimg bouudary 178 .Monumeut 27, western! of parallel 3L 20' 178 CUAPTEU VII: New monuments — Provisions of the conventions of 1882 and 1889 179 Description of all the new monuments erected; their location; kind of monument, whether stone or iron, and the inscriptions placed ou them 179-180 Description of the irou monuments 179-180 1. I'ar.allel 31^ 47' and meridian section, Monuments Nos. 1, 2, 3 180-181 Inscriptions of plates for stone monuments 181 Ditfereuces in United States and Mexican otfsets, locating monuments, Monument No. 4 181 Method of constructing the concrete base and erecting iron monuments 181 Monuments Nos. 5 to 15 182 Ditticulties from lack of water in desert 182 Monuments Nos. 16 to 39— Monument No. 40, at "corner"— silver-mining region 183 Monuments Nos. 41 to 52 — Annoyances encountercjl on meridian section 184 Organization of party 185 2. Parallel 31^ 20' 185 Monuments erected from Nogales eastward 185 Much rain encountered, Monuments Nos. 53 to 66 186 Apache outlaws, Monuments Nos. 67 to 80 187 Guadalupe Canon 187 Monuments Nos. 81 to 121 188-189 Monument No. 122, at Nogales 189 Monuments Nos. 123 to 127 • 190 3. Souora azimuth line 190 Difficult work iu the Pajaritos, Monuments Nos. 128, 129 190 Monumeut No. 152, on Lesna Mountain, Monuments Nos. 130 to 158 191 The Tule and Tinajas Altas Mountains, Monuments Nos. 159 to 205 192-193 Monument No. 204, Colorado Valley 193 Organization of party 194 Colorado River section of boundary 194 4. California azimuth line, Monuments Nos. 206 to 210 194 Monument No. 210, iu sand hills 194 Monument No. 223, below sea level, Monuments Nos. 211 to 231 195 Proposed irrigating caual 195 Monument No. 231, on crest of coast range overlooking desert 195 Monuments Nos. 232 to 252 — Monuments Nos. 246 and 247, on crest of Tecate Mountain 196 UNITED STATES AND MEXICAN BOUNDARY. 5 t'HAi'TKi! VII — Coutiuui'd. New moiiumeuts — Continued. p Destruction and reerection of Monument No. 255, Monuments Xos. 253 to 25S I97 Inscription on Monument No. 258, documents placed in foundation Xi)>5 Summary lyi) Plate 4. — Design for iron monuments Ki;) Plate 5.— Designs for sectional iron monuments l;)!) Plate 6. — Design for stone monuments njij C'HAI'TEK VIII: Photography, biology, and financial statement^ — Photographers employed at different times liiy Description of photographic instruments 1!)art of Mexico, were already on the ground; and after the usual official and personal civilities had been observed, a meeting of all the members was held at the Mexican custom-house in .Juarez on the 17th of November, 1891, when the International Boundary Commission was duly installed. Tlie proceedings at this meeting were somewhat formal in character, and resulted in the preparation and signing of a document declaring the fact of the organization of the commission; copies in both English and Spanish were then made and transmitted to the proper departments in Washington and Mexico. The preparaition of a plan of operations was now given careful consideration by the two engineers in chiel' with the assistance of the associate engineers, and was adopted on the 21st of the month. Its provisions related entirely to the methods to be pursued in making the surveys. A copy of this agreement will be found in the report of the joint commission. The Mexican section of the commission at this time was prepared to take the field in prose- cution of their surveys, having already been provided with instruments, camp equipage^ and an escort of troops. The American commission, on the contrary, had nmde no provision whatever, and there being no further duty to be performed by them until the necessary men and material conld be assembled for field operations, the joint commission separated on the 22d of November, the Mexicans to begin their survey, the Americans returning to the Eastern States to procure instruments and skilled assistants, preparatory to entering upon their part of the required work. The months of December, 1891, and January, 1892, were spent by the American commissioners in procuring instruments, engaging assistant engineers and other necessary employees, considering and devising plans for organizing the field parties and supplying them while engaged in the desert and mountain legions to be crossed during the progress of the work. 8 UNITED STATES AND MEXICAN BOUNDARY. The American members reassembled at El Paso on February 2, 1892, aud at ouce begau the work of organizing the field parties and collecting the necessary transportation. A general division of the work of the commission was decided upon, as follows : The senior commissioner, who, by designation of the President of the United States, was also the disbursing officer, to have charge, as engineer in chief, of all duty pertaining to the location, construction, and erection of monuments; the disbursement of the funds, including the payment of employees and purchase of property aud supplies. The second member to have general supervision over the running of the line in the field and the topography. The third commissioner to have general charge of the astronomical work. This division of labor was substantially adhered to throughout the continuance of operations. Following is the organization of the American commission on taking the field at El Paso in February, 1892 : J. W. Barlow, lieutenant-colonel of Engineers, commissioner, and engineer in chief; D. 1). Gaillard, first lieutenant of Engineers, commissioner; A. T. Mosmaii, assistant, Coast and Geodetic Survey, commissioner; L. Seward Terry, secretary and disbursing clerk; J. F. Hayford, assistant astronomer; J. L. Van Ornum, assistant engineer and topographer; E. L. Ingram, assistant engineer; B. A. Wood, assistant engineer; T. H. Logan, transportation clerk; J. T. Amos, field clerk; James Page, computer; P. 1). Cunin'ngham, levelman; J. H. Wright, photog- rapher; L. S. Smith, transitmau; A. F. Woolley, jr., transitmau; H. B. Finley, recorder; N. G. Ellerbe, recorder; Thomas Evans, rodman; Joe H. AVheeler, rodman; D. L. Ledbetter, rodman; C. W. Speiermann, rodman; Henry Griilin, rodman; Edmund Davis, rodman; A.J.Sampson, rodman; A. Van Ornum, chaiuman; W. T. Simpson, chainman; Luke O'Reilly, targetman; F. (x. Malloy, targetman; Albert Lang, targetman; E. Frye, targetman; J. S. Bilby, carpenter; W. J. Tucker, blacksmith; L. C. Chriss, wagon master (temporary); James Groves, chief packer. Besides these, about twenty men were employed as teamsters, packers, cooks, and hel[>ers; the aggregate number of employees of all classes being about sixty. In addition to the above, Capt. W. L. Finley, ^STinth United States Cavalry, was detailed by the War Department to act as quartermaster and commissary of subsistence for the commission ; and Capt. and Asst. Surg. E. A. Mearns, United States Army, as medical officer. By an arrangement with the Superintendent of the United States Coast and Geodetic Survey, a longitude party, consisting of C. II. Sinclair and G. li. Putnam, observers, audO. B. French, recorder, was detailed to determine the longitude, by telegraph from Los Angeles, of San Diego, Yuma, Nogales, and El Paso. A point on the boundary 100 miles west of El Paso was also included in the work of this party. The personnel of the organization was not entirely permanent; some changes among the subordinates of the engineering force occurred from time to time as contingencies arose; while among the teamsters, cooks, and laborers, the changes were quite frequent. In the higher departments the men employed continued, without exception, until the close of the work for which they were engaged. The transportation and camp equipage was purchased for the expedition, and proved to be of excellent quality, well adapted to the service required. It was at first as follows: 7 four-mule baggage wagons, 3 six-mule water-tank wagons, 3 two-nuile light spring wagons, 1 two-mule buckboard, 1 four-mule ambulance, 25 mules for packing, 83 mules in all, and 11 saddle ponies. Tiio tentage consisted of 5 otTficers' wall tents, 12 conical wall tents, 20 small wall tents. It was found unnecessary to materially increase the number of animals during the entire progress of operations; but experience taught us that a special pack train was a very expensive method of transportation, and not an absolute necessity. In May, 1892, another baggage wagon was purchased, and in the following October the pack train was greatly reduced, and later on discontinued; the animals being put in harness and employed in hauling additional wagons, which were much needed. These animals were, however, frequently used for packing on parts of the line where wagons could not be taken, and restored to the teams when the emergency had passed. Captain Finley served but a short time with the commission. His services were valuable and appreciated in procuring and organizing the transportation, but after a few days of camp exjierience UNITED STATES AND MEXICAN BOUNDARY. 9 the Captaiu, at bis own request, was relieved ou the 25th of March, 1892, and his duties transferred to Maj. T. H. Logan, formerly of the Fifth United States Infantry, who ably and zealously performed them for a period of twenty mouths, when physical incapacity — the result of an old wound — compelled his resignation. Assistant Surgeon Mearns continued with the surveying expedition, being a most efficient and careful medical officer, as well as an enthusiastic and energetic collector of specimens of natural history, until relieved by request of the medical department, in jSTovember, 1892. Dr. Mearns was restored to the commission in July following, and r.emained until the close of its field work in September, 1894. On leaving the field Dr. Mearns was assigned to professional duty at Fort Myer, Va., and, with the permission of the War Department, continued the preparation of his biological report with his usual zeal and industry. The commission, on commencing operations at El Paso, was provided, by direction of the War Department, with a military escort to accompany the expedition as a protection against Indians or other marauders. This force consisted of 20 enlisted men of the Tenth Cavalry, Lieuts. P. K. Trippe and 11. G. Paxtou commanding, and a detachment of 30 enlisted men of the Twenty-fourth Infantry, under Lieut. A. (3. Ducat, jr. The latter officer was relieved at his own request before taking the field, the detachment going out under the command of Lieut. J. K. Seyburn, Twenty- fourth lufantry, who was also the acting quartermaster and commissary of subsistence for the escort. Many changes occurred in the personnel of the escort, the troops being relieved and others substituted as the exigencies of the military service required. A complete list of the several officers and detachments serving with the commission will be given in another place. The commissioners are pleased to express their appreciation of the assistance rendered by the several officers who served with the escorts, and of the high soldierly qualities displayed by them in many difficult and laborious situations. They would also testify to the general good conduct of the enlisted men, and their usual cheerful performance of duty. During the first season's opei-ations it was deemed advisable to keep the entire organization as nearly iutact as possible, and under the constant personal supervision of the commissioners. It was also expected to work in concert with the Mexican expedition, and possibly on alternate sections of the line, which would have greatly lessened the labors of each party. Owing, however, to various causes, among which was the fact that the Americans were able, with their better organization and more practical methods, to make more rapid progress than the Mexicans, this plan could not be carried out, and it was finally determined that both parties should run the entire line, each selecting such points for astronomical determinations as might be thought proper, and afterwards compare the results. Under all the existing conditions this was the only practical method of proceeding. To carry out the work of the American commission conveniently the whole force was sub- divided into detachments as follows, the general camp moving as often as 7iecessary to keep within touch of all sections : 1. Astronomical party for determining latitude and azimuth: J. I'\ Ilayford, assistant astron- omer and observer; James Page, computer; H. B. Finley, recorder; J. S. Bilby, general helper; a cook and 2 teamsters; 1 spring wagon, 1 baggage wagon, and, when necessary, 1 water-tank wagon. 2. Tangent party for runniug the tangents: E. L. Ingram, assistant engineer and observer, in charge; N. G, Ellerbe, recorder (temporary); 2 chain men; 4 target men; 1 cook and 1 helper; 2 teamsters; 1 spring wagon, 1 baggage wagon, and 1 water- tank wagon. 3. Topographical party: J. L. van Ornum, assistant engineer, in charge: P. D. Cunningham, level man; L. S. Smith, transit man; A. F. Woolley, jr., transit man; fi rod men; 1 cook and 1 helper; 3 teamsters. The main supply camp, with the commissioners and field office, frequently included one or more of the other jiarties, and for convenience and economy combined the messing outfits. This was especially so in the beginning. Afterwards it was found expedient to separate the parties more completely. Besides the parties above enumerated there were employed with the supply camp: B. A. Wood, assistant engineer, draftsman; T. H. Logan, quartermaster and commissary; J. T. Amos, S. Doc. 217^5 10 UNITED STATES AND MEXICAN BOUNDARY. field clerk and assistant ; J. H. Wright, photogi-aplier; 1 blacksmith. 1 wheelriglit and carpenter, 1 cook and 1 helper, several teamsters and laborers. Of the cooks and teamsters but few remained permanently, and it was only after numerous trials and changes that a satisfactory complement of these indispensable employees could be obtained. A plan which worked very well was finally adopted with the teamsters of giving a monthly increase of wages for satisfactory and continuous service. The photographic work was first undertaken by J. II. Wright. He was soon found to be ill ada])ted to field service, and his place was supplied by M. .J. Lemnion for a short period. He was also unsatisfactory, and Mr. I). R. Tayne was employed iu August, 1892, and continued to the close of the entire work, rendering most faithful and efficient service in his profession as photog- rapher, and also as overseer in the erection of monuments. In conducting the survey across the desert west of the Kio Grande the expedition encountered severe difficulties. The absence of water iu the vicinity of the line for the first 50 miles, and the soft, sandy nature of the soil, which retarded the progress of wagons, being among the most serious. Men and animals were new and unseasoned to hardship, but in a few days the majority became accustomed to field life, and the work soon progressed rapidly and satisfactorily. The main camp and supply train reached Old Monument No. 4, 50 miles west of the Rio Grande, on the 20th of March, 1892. To this point all supplies were hauled across the desert from El Paso. After leaving the vicinity of the river, water was obtained from Strauss and Lanark, stations on the Southern Pacific Railway, by hauling from 10 to 15 miles. While camped at Old Monument No. 4, and its vicinity, water was obtained from a well 3 miles north of this monument. This well is 100 feet deep, the water raised by windmill and horsepower for supplying a large herd of cattle owned by a ^Irs. Wragg. The quantity was quite abundant but the quality bad, being strongly alkaline. Beyond, in New Mexico and southeastern Arizona, water was obtained with less difficulty, several natural springs and a number of ranchmen's wells having been found available. From this point (Monument No. 4) westward advantage was taken of the Southern Pacific Railway in the transportation of supplies from the most convenient point of purchase to the stations nearest the field of operations, which method greatly relieved the strain upon the animals of the expedition. The survey continued without serious inconvenience, reaching the "corner" at the western extremity of the boundary on parallel 31° 47' iu the latter part of April. The main camj) remained here from the 22d of April until the 18th of May. At the latter date the astronomical observa- tions had been completed, including an exchange of telegraphic signals between this station and El Paso. For the latter puri)ose a field telegrai)h line was erected to this point from the railroad at Separ, about 35 miles distant. The material for the line was loaned by authority of Gen. A. W. Greeley, Chief of the Signal Service of the War Department, and put up under the direction of Lieut. Frank Greene, United States Signal Service, by a company of the Twenty-fourth United States Infantry, Bvt. Maj. James N. Morgan, commanding. The wagon transportation was supplied from the boundary train. This work was performed with remarkable expedition. The line was in working order on the evening of the fifth day after the material arrived. It was used four nights for excihauge of signals, and immediately removed. Before moving this camp the tangent and topographical parties carried their work well along the meridian southward, and were able to obtain water from Mosquito Springs, 15 miles distant and near the line, on the Mexican side. The water in the vicinity of camp at the "corner" was scarce and of poor quality, a moderate supply being obtained from a well owned by Mr. Boyle, 3 miles west of camp. From the wells of Mr. Rector, several miles south, some water was obtained, and also from the Garrizalillo Springs, 15 miles eastward. Wood in abundance and of excellent quality was always available, being generally the roots of dead mesquite, which were obtained with little labor and made the best of fuel for cooking. For evening campfires grease wood, yucca, and the branches and roots of mesquite served a good purpose. For a time a supply station was established on the railroad at Separ, whence stores were liauled by the commission teams to the camps along the parallel of 31° 20' as far as San Bernardino, UNITED STATES AND MEXICAN BOUNDARY. 1 1 some miles west of tbe Guadalupe Mountains. From the latter point, until within reach of Nogales, a supply station was established near Bisbee, on the Arizona and Southeastern Railroad, which point was easily accessible by the wagons of the expedition for a distance of 100 miles along the boundary. The main camp reached San Bernardino on the 26th of July, and all the work of the survey was completed in that vicinity during the month of August. On August C a detachment of men and teams, under T. H. Logan, was sent overland 240 miles to El Paso to take up the work of monument ei'ectiou on the parallel of 31^ 47'. This transportation consisted of 4 baggage wagons, 1 water-tank wagon, 1 spring wagon, 1 buckboard, and 2 saddle ponies. At El Paso another spring wagon with 2 horses was purchased for this party, and later on a water-tank wagon and 1 baggage wagon were added, the animals being supplied from the 1.5 pack mules which had been sent from the main camp for duty with the monument party. This party when fully organized consisted of the following men and transportation: One com- missioner, Lieut. Col. J. W. Barlow, in general charge; E. L. Ingram, assistant engineer, in charge of location party; T. H. Logan, quartermaster, and in charge of working party; D. R. Payne, photographer and general assistant; 1 stone mason, 1 blacksmith, 1 rodman, 7 teamsters, 4 laborers, 1 cook, and 2 helpers — a total of 21 persons. A Mexican party, consisting of one commissioner, an assistant engineer with helpers, and appropriate transportation, accompanied this party and assisted in the location of monuments. The work of construction and erection was done wholly by the American section. A detachment of 12 enlisted men from the Twenty-fourth Infantry and 2 troopers from the First Cavalry were attached as an escort for this party, and were provided with a baggage wagon and 4 mules for transportation. This monument party continued work until the close of November, erecting monuments along the parallel of 31° 47' and the meridian section to the parallel of 31° 20'. It then moved overland and joined the main survey camp near La Noria, Ariz. The entire force was now engaged in completing the survey of the line along parallel 31° 20' to the angle at the one hundred and eleventh meridian, where the boundary changes its direction. The weather in this elevated mountain region having become very trying upon the men in the field, and it being very important that the desert country adjoining the Colorado River be surveyed before the heat of summer should make that work impracticable, it was decided to transfer the entire expedition to Yuma and carry on the survey from the Colorado River across the deserts on either side during the winter and early spring months. The expense of shipping by rail was found to be so great that it was decided to move over- land, and to accomplish this with the least possible delay in prosecuting the fleldwork, the trans- portation was divided. About one-half was started via Tucson and along the wagon road near the Southern Pacific Railway on the lath of December, 1892. This detachment Safely reached Yuma on the 31st of the month. The other half remained with the parties which were completing the survey in the vicinity of Nogales and followed early in January, 1893. The engineers and others engaged upon the survey, with their instruments and i)ersonal baggage, were sent by rail to Yuma, reaching that point in time to commence work at once, with the aid of the first section of the transportation previously sent over. Two survey parties were here organized from the whole force to push the surveys both east and west from the Colorado River, with a view to completing the work on the Yuma and Colorado deserts before the advent of hot weather. After finishing at Yuma the astronomical determinations for latitude and azimuth, and connecting the observatory with old Monument No. VI, on the west side of the river, and old Monument No. II, on the east side, by triangulation, the astronomical party was discontinued as a separate organization and its menjbers assigned to duty with the two line parties. The entire organization was now divided as follows: 1. Survey party for tangent work and topography from the Colorado to the Pacific: E. L. Ingram, assistant engineer in charge, running theodolite; P. D. Cunningham, trausitmau; H. B. Fiuley, transitman ; C. W. Spiermann, levelman; A. Lang, in charge of heliotrope; 9 rodmen, 1 cook and 1 helper, 4 teamsters, 2 packers, and 1 guide— a total of 23 persons. 12 UNITED STATES AND MEXICAN BOUNDARY. The transportation of this party consisted of 2 baggage wagons, :i water-tanlv wagon, a light spring wagon, Ki draft mules, and 2 riding horses. 2. Survey party for operations east of the Colorado to the one hundred and eleventh meridian: J. L. Van Ornuin, assistant engineer, in charge of topography; J. Y. Uayford, assistant engineer, in charge of the azimuth line; L. S. Smith, transitman; James Page, transitman; Ernst Franke, levelman; J. T. Amos, clerk and assistant quartermaster; 3 heliotropers, 9 rodmen, 1 mechanic, 1 packer, 4 teamsters, 2 cooks, and 3 laborers— a total of 29 persons. The transportation for this party consisted of i baggage wagons, 2 water-tank wagons, 2 spring wagons, C pack and 5 riding animals — a total of 41 animals. To supply these parties with rations and forage, the remainder of the transportation was kept busy hauling from Yuma to the respective camps until the distance became too great for economical service from this point. When the party working toward the coast had crossed the desert and entered the region of the Coast Eauge of mountains its base of supplies was changed to San Diego, and to supply the the party working eastward, after getting beyond convenient wagon communication with Yuma, stores were shipped by rail to points on the Southern I'aciflc Eailway and hauled, thence to the line by wagons. At Yuma the commission office, including the draftsman and photographer, was retained until late in May, when that camp was abandoned. The senior commissioner then took charge of the monument party just organized for work on parallel 31° 20', i)roceeding to i!fogales for this purpose. The second commissioner went to Buenos Ayres, near the boundary, south of Tucson, to take charge of the survey party approaching that point from the west, and the third commissioner went to San 1 )iego to supervise the party working in that direction tlirough the Coast Range of mountains. The monument party was made up from the men and transportation which had been engaged in hauling between Yuma and the survey camps, with some necessary additions and modifications. Its organization was as follows: One commissioner, Lieut. Col. J. W. Barlow; B. A. Wood, assistant engineer; T. H. Logan, quartermaster and overseer; D. E. Payne, photographer and painter; 2 rodmen, 1 blacksmith, 1 stone mason, it teamsters, 5 laborers, 1 cook, and 2 helpers; a total of 21 persons. The transportation consisted of 3 baggage wagons, 1 truck wagon, 2 water-tank wagons, 2 spring wagons, 5 horses, and 24 mules. This party as above organized assembled at 2fogales in May, 1893, and took up the work of locating and erecting monuments on parallel 31° 20', eastward from the one hundred and eleventh meridian. These three organizations were continued, with some changes, until the completion of their duties. During this season the aggregate force employed reached the maxinuim, being 80 men and 22 wagons of all classes. The party working westward completed the survey to the Pacitic September 23, lS9.i, and, with the exception of those retained for special office work, the members were discharged and the transportation sold. The other party was engaged on its work in the field until the 20th of October, when, having reached the one hundred and eleventh meridian, it was transferred to Tucson, where the disbursing office had been previously established, and there disbanded. The majority of the men were discharged, and such transportation as was no longer required for the monument party was sold. The assistant engineers and instrument men were transferred to the office in San Diego for temporary service reducing notes and preparing field maps of their work. After the survey parties were disbanded, the only field force retained was the monument party, which, having finished its work on parallel 31° 20' and the meridian section, in aSfovember, 1893, took up the work of locating and erecting monuments westward from the one hundred and eleventh meridian. On taking the field again, after its reorganization at Tucson, this party was considerably strengthened to meet the increased difficulties on this part of the boundary, and consisted of the following men and transportation: One commissioner, Lieut. Col. J. W. Barlow; B. A.Wood, assistant engineer, in special charge of location; D. It. Payne, photographer and overseer; J. T. UNITED STATES AND MEXICAN BOUNDARY. 13 Amos, quartermaster ami clerk; M. E. Cnnniugham, wagon master; Jolm Duncan, foreman of laborers* Joe H. Wheeler, I'odman; 1 blacksmith, 1 stone mason, 9 laborers, 9 teamsters, 2 cooks, and 2 helpers— a total of 31 men; 2 spring wagons, 1 buckboard, 3 water-tank wagons, 5 baggage wagons, 1 truck wagon, 5 horses, and 36 mules. The commissioner met with a severe accident early in December which compelled him to leave the field for several months. General charge of operations was then given to B. A. Wood, assistant engineer, whose zeal, energy, and intelligence are worthy of special mention in connection with this part of his service. The above organization of the monument party was continued while operating between the one hundred and eleventh meridian and the Colorado Eiver. On reaching Yuma the question of sui)ply became much simplified, and the force was considerably reduced. The supply camp, hitherto a necessity, was discontinued, and the surplus transportation sent overland under charge of Mr. Amos, to San Diego, where it was subsequently sold. Mr. Wood's services being required in the office at San Diego, ]Mr. Ingram relieved him at this point. The following organization was that employed in monument location and erection from the ('olorado Eiver to the Pacific: E. L. Ingram, assistant engineer, in charge; D. R. Payne, overseer and photographer; M. E. Cunningham, wagon master; 1 blacksmith, 1 cook, 1 helper, 2 packers, 3 teamsters, 5 laborers; a total of 10 persons. The transportation consisted of 1 spring wagon, 1 buckboard, 2 baggage wagons, 2 water- tank wagons, 1 truck wagon, 3 horses, and 26 mules. Theie were employed in the office at San Diego at this time upon clerical and preliminary map work : L. Seward Terry, secretary and disbursing clerk ; J. L. Van Ornum, assistant engineer; J. F. Hayford, assistant engineer; B. A. Wood, assistant engineer; James Page, computer; P. D. Cunningham, computer; P. A. Mosman, computer; Joseph Thompson, assistant clerk. This otlice force was reduced as rapidly as the services of these assistants could be spared. The monument party completed the erection of monuments to the Pacific in June, 1894, when the party was disbanded and the transportation and cami) equipage sold. The assistant engineer and the photographer joined the office force in San Diego, and were engaged in preparing the records of their work until the fall, when the entire commission adjourned to ineet again iu Washington in October, 1895, to complete the reports and maps of the expedition. It has been previously stated that the principal assistants, who were engaged at the begin- ning of operations, continued with the expedition until the close of the work for which they were employed. It is proper to add in the case of each of these gentlemen, viz, Messrs. Van Ornum, Hayford, Ingram, and Wood, that they all brought to bear upon their duties rare intelligence and excellent previous training, and throughout the difficult and arduous work devolving upon them were ever willing and prompt to further the interests of the commission. To them is due large ci-edit for the successful completion of the survey and the erection of the monuments. The same might be said of Mr. L. S. Smith, who, holding the position of transitman from the beginning, was advanced in pay and responsibility, and is especially deserving of commendation for efficiency in investigating the causes of stadia error. The services of Mr. A. F. Woolley, jr., transitman, were also valuable and appreciated during the several months that he remained with the expedition. It is also ijroper to mention, in this connection, the services of Mr. James Page, computer and transitman, for thorough efficiency, and those of Mr. P. D. Cunningham, a most zealous and conscientious young engineer, who rose from the position of levelman to that of assistant engineer. Messrs. C. W. Speiermann, Ernst Franke, and H. B. Finley were faithful, industrious, and tlioroughly conscientious assistants, who rose from subordinate positions to places of higher responsibility and pay during the progress of their work. Maj. T. H. Logan deserves especial mention for rare skill, zeal, and industry in managing men and transportation in the field, and would have undoubtedly continued to the end except for physical disability. Mr. L. Seward Terry, secretary and disbursing clerk, performed his delicate and responsible duties from the beginning to the close of operations with entire satisfaction, combining in his methods clerical ability of high order with rapidity of execution and extreme accuracy of detail. 14 UNITED STATES AND MEXICAN BOUNDARY. Mr. J. T. Amos, assistaut clerk and assistaut quartermaster, was a man of ability and sterling- integrity, conscientiously performing the duties assigned to him. Among the more subordinate members of the expedition were several whose good conduct and pluck under adverse conditions were conspicuous, serving in great measure to prevent accidents and delays in the field. In this list should be mentioned M. E. Cunningham, hired as teamster, and afterwards promoted to wagon master; John Duncan, also a teamster, and promoted to master laborer upon monument work. Among the most deserving rodmen were Joe H. Wheeler, Thomas Evans, Albert Lang, W. T. Simpson, Albert Davis, and Eugene Gill. Of the teamsters and packers whose services M'ere specially praiseworthy were W. P. Blair, W. F. Mallory, Jack Nimo, Andrew Linder, John Groves, Charles Kohrer, and Eobert Lynch. Officers of c rt wilh Intel-national Boundary Datf cif joinin^r.' I>ate of relii A. C. Ducat, jr.... P.E. Trippe -T. K. Sejburn E. A.Mearns :;. G.Paxton T.G.IrvinJr F.N.Kingsburi-.. W. P. Jackson .... W.C.Eawolle Capta R. B. Bryan First lientenaiit | do J. R. Seyburn Second lieutenant Twenty-fourth Infantry. First lieutenant Twenty-lnurlb Infantry do Tenth Cavalry Second lientenant Twenty-fourth Infantry Captain Medical Depart Second lieutenant ! Tenth Cavalry First lieutenant Second Cavalry , Apr. Captain , do I July Second lieutenant Twenty-fourth Infantry 1 Aug, 23, 1892 Feb. 9, 1892 29, 1892 Feb. 20,1892 9, 1892 Aug. 10, 1892 id Cavalry M.C.Wossells ' Captain do H. E. McYay First lieutenant i Medical Departine F. A. Winter do G. R. McMaster , Second lieutenant ] Twcntyfourth Infantry E. A. Mearns Captain ■ Medical Department S. V. Ham Second lieutenant , Twenty-fourth Infantry B. W. Leavell First lientenant do W. H. Bean do , Second Cavalry Dec. .Do. Sept. 1,1892 Apr. -,1893 Sept. 14, 1892 Kov. 9,1892 Nov. -,1892 Dec. 6.1892 .do Apr. 17,1893 Apr. 17, 1893 Nov. -, 1893 June — , 1893 Oct. — , 1893 July 22, 1893 Sept. 8, 1894 Oct. 10, 1893 Nov. 5, 1893 Oct. 19, 1893 Dec. 20, 1893 Dec. 20, 1893 Aug. 4, 1894 Aug. 19, 1894 Oct. 2,1894 Xumher of en listed men > International Bonndary Commisaii ' January February I Maicb I Vpiil • Ma\ I July Septi 1 ( )( toher NoAen.bii Dei emlx i Date. 1892 October Deceinbei Januar\ M in h Api 1893. M.} 29 1 lanuar\ J-> June 29 Uhiuir\ 15 July 23 i Mircli 4> August 13 Apnl 41 Sept. ml). 1 15 Ma\ 43 1 UNITED STATES AND MEXICAN BOUNDARY. 15 CHAPTER II. GENERAL DESCRIPTION OF THE COUNTRY ADJACENT TO THE INTERNATIONAL BOUNDARY LINE. Any general description of the country adjacent to the international boundary line between the Rio Grande and the Pacific must of necessity give au incomplete idea of its appearance to one unfamiliar with the arid regions and the peculiar character of its fauna and tloia, for probably in no section of the Fnited States of equal extent is the rainfall so small and the summer heat so intense. The average annual precipitation along the entire boundary is but about 8 inches, and on the Yuma and Colorado deserts but 2 or 3 inches, a deficiency which will be made more significant to the ordinary reader when it is stated that the boundary line, although having a total length of about 700 miles, crosses but five permanent running streams between the Rio Grande and the Pacific and this, too, although crossing most valleys and mountain ranges nearly at right angles, the direction most favorable for encountering all existing streams. From the summer of 1890 to that of 1893 the entire country between tlie Rio Grande and the Colorado suffered from a drought of unprecedented duration and severity, the effects of which were intensified by the overstocked condition of the ranges. This state of affairs added greatly to the difficulties and expense of the survey. Vegetation was parched, water holes dried up, and scarcely any grass was left by the famishing cattle. This long drought was broken by abundant rains in July and August, 1893, but not until the stock-raising interests had suffered severely. The small rainfall of this region generally occurs at two periods of the year — midwinter and midsummer — the latter rainfall the greater and by far the nu)St important; consequently this period is known as the "rainy season." The summer rains generally commence about the 1st of July iind cease sometime between the 1st and 20th of September. It is soon after the first of these rains that vegetation in this region begins to assume a spring-like character. Leaves burst forth, the hills and valleys are covered with grass, and a bewildering profusion of wild flowers covers the entire country. As if conscious of the short duration of the rainy season, these grow with great rapidity, and their seeds mature ere the rains cease. In a month or so thereafter they have again assumed the somber colors typical of fall and winter. Thus in the short space of three or four mouths vegetation here enjoys its spring, its summer, and its autumn. Before going more into details it may be well to note certain general characteristics of this I'egion which at once strike the ordinary traveler. These are the bare, jagged mountains rising out of the plaius " like islands from the sea;" the abundance of the evidences of volcanic action in times geologically recent; the parallelism of the mountain ranges with one another, aiul with the Pacific Coast; the general absence of trees; the preponderance of evergreen vegetation, and its dull, leaden-green hue; tlie prevalence of thorns in nearly all vegetation; the general absence of fragrance in flowers; the resinous character of the odor of the most common trees and shrubs, and the abundance and large size of the cactus. The entire country along the boundary is thinly settled, the principal settlements within 20 miles of the boundary on either side being at Lake Palomas, Hachita, the Sulphur Spring Valley, La Morita, the San Pedro Valley, the Huachuca Mountains, the Santa Cruz Valley, Oro Blanco, Arivaca, the Baboquivari Valley, the Papago rancherias of Pozo Vei'de, Cobota, and Pozo de Luis, the Sonoyta Valley, the Colorado River Valley, and tlie country between the summit of the Coast Range and the Pacific. The only towns within the limits above mentioned are Bisbee, Santa Cruz, Xogales, Yuma, and San Diego. With the exception of these towns and settlements the rest of this zone of about 24,000 square miles contains less than loo permanent inhabitants. Milling and stock raising comprise the principal occupations of the settlers, but at the time of the survey both of these were in a very depressed condition, owing in the one case to the low price of silver, and in the other to tlie long drought of three years' duration and to the overstocked condition of the ranges. An exception to this depression, however, was found at Bisbee, Ariz., where are located the mines and reducing works of the Copper Queen Company, wliich are reported as returning excellent profits to the owners. Although the soil in many places is very fertile, yet the great scarcity of water renders it impossible for the inhabitants to carry on agriculture, except to a very limited extent. 16 UNITED STATES AND MEXICAN BOUNDARY. But for sandy stretches on tbe deserts many miles in length, and rough passes through the mountains, the natural roads along the boundary are very good. With the exception of the Colorado River section, there exists, however, no practicable wagon road along any one of the six sections of the boundary line and witliiu a reasonable distance of it, which lies either entirely iu the United States or in Mexico, a fact which even now, in spite of the small number of inhabitants along the boundary is the cause of considerable unavoidable inconvenience to travelers when customs otlicials are encountered. It is rather remarkable that an arbitrarily chosen boundary line like the one under discussion, should, between the Rio Grande and the Colorado River, follow almost exactly the summit of the divide which separates the waters flowing north into the United States from those flowing south into Mexico. Having given the foregoing general description of the boundary line, the different sections, beginning at the Rio Grande, will be briefly described in turn. ^Section 1, jxtraUel 31° 47'. — The Rio Grande in the vicinity of El Paso, Tex., is a variable stream with turbid waters carrying an immense amount of sediment, and as a consequence it is bordered by alluvial bottoms, through which by erosion, it is continually changing its bed. Floods generally occur in June and July, but during the greater part of the year the volume of flow is comparatively small and the river can readily be forded. In dry seasons it ceases entirely to flow for weeks at a time. In the immediate vicinity of the Initial Point of the boundary the mountains on either side encroach on the river, and as a consequence its banks there are more stable and its changes of bed smaller in extent. Leaving the Rio Graude the boundary line crosses the Muleros Mountains, a rugged, broken mass, almost destitute of vegetation, composed of a curious and bewildering intermixture of stratified limestone and igneous rocks. Between H and 3 miles west of the summit of the Muleros Mountains the line reaches, by a rather abrupt ascent, the surface of a wide, sandy mesa, about 4,000 feet above sea level, over which it continues for a distance of about 48 miles. Mile after mile this mesa stretches in an endless monotony of fiat, rolling ridges and shallow valleys, with not a tree to relieve the dreary aspect of the landscape. The earth is covered with a coarse, brownish- yellow sand, which supports, in places, an excellent growth of black grama grass, and a stunted growth of greasewood, mesquito, yucca, and " ochetilla" (Fouquieria splendens). On the edge of this mesa lies the Sierra del Potrillo, a cluster of bare, rounded mountains, giving evidence, by extinct craters and the extent of the " mal i)ais" in its vicinity, of considerable volcanic activity in the past. Toward its western edge the mesa becomes more rolling, and rocky hills covered with broken lava are scattered at intervals over its surface. Descending from the mesa by a well-marked and rather abrupt descent, the line passes for a distance of about 17 miles over a broad, level valley, bare of vegetation, and having a soil composed of a stiff clay sediment, which becomes almost impassable when wet. This valley lies between tbe Floridas and the Tres Ilermanas mountains, and extends in a north and south direction. Down this valley, and connecting at Deming, N. Mex., with the Southern Pacific Railway, a railroad luid been located a year or two previously, and the grading extended from Deming to a )>oiiit several miles below the boundary, when work was suspended on account of financial ditticulties. Anticipating the completion of this railroad a town site was laid out where it crossed the boundary line; lots were sold, and a small settlement, bearing the name of Columbus, was started. A mile or two south of this settlement commences a chain of shallow, marshy lakes, whose waters are strongly impregnated with alkali, and which are connected with one another by a small running stream. This chain, called Lake Palomas, terminates in a broad, shallow lake, several square miles in area, with no visible outlet. When the water in this lake is low its shores are covered with an alkaline deposit, 2 or 3 inches in depth, resembling snow. About 5 miles south of the boundary, on the western edge of the chain of lakes, and near some line, bold springs, was located the Mexican custom-house, which had been recently moved there from Asceuciou as a ])unishment for an outbreak against the Government at that place. One troop of cavalry was quartered there at the time, giving to the place an unexi)ected appear- ance of life and activity. The peculiar chain of lakes constituting Lake Palomas is supposed to l)e h but little profit is derived, owing to the scarcity of water and the cost of transportation. A good road leads from this vicinity, via Carrizalillo Spring, to Deming, X. Mex., and another, via Hachita, to Separ, a station on the Southern Pacific Railway. Sevtion 3, the meridian section. — Commencing nt Monument 40 the lines passes, for a distance of about 5 miles, over the Apache Mouutaitis and then over a broad, fertile valley, covered with a thick growth of mesquite, greasewood, etc., on its northern and western border, and with excellent grass in other places. This valley is bounded on the northwest by the majestic Sierra de la Hacheta (locally known as the Big Hatchet Jlountain), and stretches away to the south and east to unite with the valley of the Corralitos Eiver. A little over a mile east of Monument 4(1 are situated the " Ojos de los Mosquitos," yielding a plentiful supply of water, impregnated with alkali. From this point good roads lead to Carri- zalillo Si>ring, Dog Spring, Ascencion, and the settlements along the Corralitos River. From Monument 4(5 the portion of the valley over which the line passes rises with a gentle slope toward the south, until the foothills of the Dog Mountains are reached, when the section terminates at an elevation of about 4,900 feet above sea level. This point is marked by Monument 53, a fine, cut-stone monument, identical in appearance with that marking the beginning of the section. Section S, parallel 31° 20'. — From Monument 53 the line passes for several miles over the rough hills south of the Dog Mountains, thence across the east branch of the Playas Valley, the White- water Hills, the west branch of the Playas Valley, and the San Luis Mountains, all in a distance of about 35 miles. A little over a mile north of Monument 55 is Dog Spring (Ojo del Perro), at which is located a cattle ranch, and which furnishes a supply of excellent water suflicient for several thousand head of animals. The country along this part of the boundary is covered with excellent grass, which attbrds xJasturage for numerous cattle and horses. A little over (5 miles north of Monument 58 is Alamo Hueco Spring, where the supply of water is both excellent and abundant. At the south end of the Whitewater Hills water can generally be found, but in very dry seasons the quality is poor and the supply very limited. In such cases, however, a plentiful supply can be obtained about 6 miles southwest of this point, at " San Francisco Water." This entire region abounds in game, and is a veritable hunter's paradise. Hundreds of antelope roam over the valleys, and deer, bear, and turkeys are plentiful in the mountains. On the summit of the San Luis range, which here forms the ''continental divide," the boundary line attains its greatest elevation, about 6,000 feet above the sea. About 4i miles north of the boundary the road from Dog Spring crosses the mountains by an excellent pass known as San Luis Pass. Two miles north of the line is another pass less traveled than the former, but shortening the distance considerably. 18 UNITED STATES AND MEXICAN BOUNDARY. To the iioi'th of San Luis i'ass the range gradually rises in height to Animas Peak, which prac- tically marks its northern extremity. To the south of the pas.s the mountains become higher anil more rugged, and the range stretches south into Mexico as far as the eye can see, forming here the axis of the Sierra Madre, and presenting a wild and picturescjue beauty singularly fascinating. On the foothills and lower slopes the prevailing rock is red basalt, while on the summit and upper slopes it is apparently an igneous rock of volcanic origin resembling granite. The valleys at the base and lower slopes are dotted with evergreen oaks, the acorns affording food for thousands of wild pigeons, while on the upper slopes are dense forests of junii^er, pine, fir, and Arizona cypress. A few hundred yards northeast of Monument 66 is situated San Luis Spring, which affords a moderate supply of fair water, and from which good roads lead to Lordsbiirg and Separ, on the Southern Pacific Railway. No settlements are now found in this vicinity, those at one time existing having been abandoned during the raid of the noted Apache chief, Geronimo. Pros- pective settlers are now deterred through fear of a small band of renegade Chir-ica-hua Apaches, who, under the leadership of the redoubtable " Kid," still continue their murderous raids in the vicinity, and as yet have succeeded in escaping the pursuit of the numerous detachments of troops .sent against them. Leaving the San Luis Mountains the line passes over the Animas Valley and the Guadalujie Mountains and descends into the San Bernardino Valley. The Guadalupe Mountains where crossed by the Ijoundary line are in reality but the broken. Jagged edge of a terrace, marking a descent of about 1,400 feet from the Animas Valley to the San Bernardino Valley. For the most part bare of trees, they present to the eye a confused mass of peaks, crags, ridges, and cafions. Through these the old emigrant road makes its way by sudden turns and steep descents until it enters the Guadalupe Cafion, which gradually widens, improving tiie character of the road thereby. This rough and difficult passage, called Guadalupe Pass, is the only route through the mountains within many miles north or south of the boundary. IVlonument 71 in these mountains marks the intersection of the boundary line between Arizona and New Mexico with the international boundary line. By local repute the boundary line between Souora and Chihuahua is said to intersect the international boundary line at the same spot; but as this boundary line is generally shown as the axis of the Sierra Madre, it would seem that the intersection should occur at Monument 65, on the San Luis Mountains. Water was found at a small spring in Guadalupe Canon, and also in wells near the point where the boundary line crosses the canon. In San Bernardino Valley the line crossed the first running water since leaving the Eio Grande, over 102 miles distant. In this valley, a few miles north of the boundary line, rises San Bernardino Creek, the most northerly tributary of the Yaqui River. Numerous springs are found in the valley, and thousands of cattle seek pasture on its marshy surface. A large ranch is established at some fine springs just north of the line, while a short distance south of the line are found the ruins of a bastioned adobe fort and numerous outbuildings, marking the site of a floui-ishing presidio established during the Spanish rule. Good roads lead from San Bernardino to Tombstone and Bisbee. Crossing the gravelly mesa west of the San Bernardino Valley the line passes over the Per- rilla Mountains, which, with the Swisshelm Mountains to the north, form a spar of the Chir-i-ca-hua Mountains, and divide the San Bernardino Valley from the Sulphur Spring Valley. A short distance south of the line is a very j)rominent, flat-crested peak, Cerro Gallardo, locally known also as " Niggerhead," which forms a prominent landmark. About 2 miles southeast of Monument SI was located a " vinateria," where a supply of good water was obtained from a shallow well. From the Perrilla Mountains the land slopes gradually and uniformly down to the middle of the valley, and by a similarly long and tedious slope the foothills of the Mule Mountains are reached. Several settlements are located in this valley, as water can always be obtained by sinking wells to a moderate depth. Crossing this valley the boundary line passes through a gap near the southeastern extremity of the Mule Mountains, thence along the north slope of the valley lying between the Mule Mountains and the Sierra San Jose until the valley of the San Pedro River is reached. About 10 miles north of the boundary line, in the Mule Mountains, is located the prosperous mining town of Bisbee, a place of about 2,000 inhabitants. About 20 miles to the northwest of UNITED STATES AND MEXICAN BOUNDARY. 19 Bisbee is Tombstone, once one of the great mining camps of the world, but now containing about 1,500 inhabitants, and bearing on all sides evidences of depression and decay. About 4 miles south of Monument 90 is located the Mexican customhouse of La Morita, recently moved there from the San Pedro River. From the Mule Mountains to the end of parallel 31° 20' the country is fairly thickly settled, and the distance between watering places nowhere exceeds 10 or 12 miles; consequently in this region it is not necessary, as heretofore, to describe all available water in detail. The San Pedro lliver, in the vicinity of the boundary line, is ordinarily a stream of about 15 feet in width and 6 or 8 inches in depth, fringed with a fine growth of cottonwood and willow, and possessing the distinction of being the only southern tributary of the Gila wliich has an uninterrupted flow throughout its entire length. The valley bordering the river is very fertile, but the bed of the river has sunk so deep that irrigation is attended with many obstacles, and consequently but a very limited portion of the valley is under cultivation. On the east bank of the San Pedro, a few miles south of the line, is the little village of San Pedro, where until very recently was located the Mexican customhouse, now removed to La Morita. A good road leads from Benson, through the Sau Pedro Valley, to the higli table-lands of northern Souora. From the San Pedro River the slope rises rapidly, but uniformly, to the Huacliuca Mountains, over the southeastern end of which the line passes at an elevation of about 6,100 feet. These mountains and their lower slopes are covered with a heavy timber growth generally similar to that found on the San Luis ]\Iountains. They are the highest embraced within the limits of the survey, attaining, at a point about 4 miles noi'th of the boundary, an elevation of about 9,400 feet. At the foot of the mountains, about 15 miles north of the line, is beautifully situated Fort Huachuca, an important post garrisoned by four companies of infantry and two of cavalry. From the Huachuca Mountains to the San Rafael Valley the line passes over a beautifully picturesque grazing country, badly cut up by canons, from which it descends into the San Rafael Valley, the name by which is known that portion of the valley of the Santa Cruz River lying east of the Patagonia Mountains and adjacent to the boundary line. The Santa Cruz River rises in the hills a few miles north of the boundary, flows south into Mexico for about 15 miles, then turns around the south end of the Patagonia Mountains and flows north, again crossing the boundary line, and continuing its generally northern direction, flowing for a short distance and then sinking beneath the sands, to reappear again, until it disappears finally a short distance beyond Tucson. The stream is bordered by a noble growth of cottonwoods, whose bright green leaves were a welcome sight after the ashen-green color of the vegetation previously encountered. That portion of the valley of the river which lies in JNIexico is very fertile, and a considerable part of it is under cultivation. The little town of Santa Cruz is picturesquely situated in this valley at the foot of the mountains, about 7i miles south of the line. In the San Rafael Valley, at La Noria, is situated the United States custom house, from which a rough road leads to Crittenden, on the Arizona and New Mexico Railway, and a good road down the Santa Cruz Valley and around the Patagonia Mountains to Is'ogales. Leaving the San Rafael Valley the line passes over the rough, oak-clad foothills of the Patagonia Mountains, which it crosses in a gap a short distance north of San Antonio Pass, at an elevation of about 5,(i00 feet. These mountains are quite pictures(iue, being heavily wooded, the growth consisting principally of oak, with a few conifers on the higher slopes. They are rich in minerals and contain some of the first mines worked by Americans in Arizona. The San Antonio Pass, an excellent one for pack animals, crosses this range a little south of the line and cuts off the tedious detour along the Santa Cruz Valley, From the Patagonia Mountains the line descends over a badly cut up hill country to the Santa Cruz River, which it crosses for the second time. The elevation of the river is about 3,675 feet, and it is somewhat singular that the two lowest points on the boundary between the west end of parallel 31° 20' and the Initial Point on the Rio Grande differ in elevation less than 16 feet from each other, and less than 23 feet from the Initial Point on the Rio Grande. The two points in question are at San Bernardino Creek and the second crossing of the Santa Cruz River, the former being the lower of the two. From the Santa Cruz the line begins to ascend, passing over a hilly country, the broken and cut up character of which increases to the termination of the line in the Sierra de los Pa,jaritos at an elevation of about 4,800 feet. 20 UNITED STATES AND MEXICAN BOUNDARY. Nestling amidst tlie bills, in a narrow valley abont 8 miles east of the termination of parallel 31° 20', lies the town of Nogales, containing about 3,500 inhabitants, and built on both sides of the boundary line, which passes tangent to the south front of the buildings on the United States side of International street. This street has a width of about 50 feet and lies entirely within Mexican territory. The grasping and overreaching action of the United States settlers in building right up to the boundary line results in many inconveniences to the customs officials and peace officers of the United States, who, in order to patrol this important street, must rely for permission to do so upon the kindness and courtesy of the Mexican officials. Open, yet lawful, evasions of customs duties result from the position of this street with reference to the boundary line, as in one somewhat noted case observed where liquors of United States manufacture were sold to the consumer in a saloon on the United States side of the line, while cigars of Mexican manufacture were sold by the same establishment from a stand in front of the saloon but on the Mexican side of the line, thus enabling consumers from either side to obtain, duty free, liquors and cigars from the same establishment. At Nogales are located both the United States and Mexican custom-houses, the latter a flne^ ■well-arranged building, the annual customs receipts of which are very large, as Nogalesis situated on the railway which runs from Benson, Ariz., to Guaymas, on the Gulf of California, and is the only railway entering Mexico between the Rio Grande and the Pacific. Good roads lead from Nogales north t(5 Tucson, and south to Magdalena, Herniosillo, and Guaymas. Section 4, the azimuth line from the west end of parallel 31° 20' to the Colorado River. — A fine masonry monument. No. 127, situated in the Sierra de los Pajaritos, on the north slope of a steep ridge, marks the beginning of this section of the boundary line, which for about 21 miles continues in these mountains. The term " Sierra," as applied to them, is a decided misnomer, for unlike the mountains pre- viously encountered, they consist of a confused mass of rocky crags, peaks, fiat-topped mountains with vertical sides, enormous trachyte dykes, steep, narrow ridges, and deep canons, all mingled in startling confusion. The most common rocks are porphyry, red basalt, syenite, and volcanic breccia. Gold and silver veins are found in numerous places, and placer gold is obtained in most of the caiions. The mountains are covered with a fine growth of evergreen oak, juniper, and raanzanita, while magnificent walnut, sycamore, and ash trees line the caiions. Excellent grass covers the hills; thousands of beautiful wild flowers spring up on all sides during the rainy season; game is abundant, and the climate unsurpassed. From the highest part of these mountains the view is beautiful beyond description, and stretches away for 75 or 100 miles in every direction. Throughout this entire region, probably one of the roughest and most cut up in North America, there are no roads and but a few blind trails. Little or no water is to be found during the dry season, except by digging, although there is evidently a considerable underground drainage, as the Altar lliver, Arivaca Creek, and Nogales Creek, all permanent streams, derive their waters from the drainage of. these mountains, which were notable, not only on account of their beauty, but also because they constituted the last timber-covered mountains encountered on the survey until the Coast Kange was reached, and because in them was seen for the first time the strange and ungainly "giant cactus" (cereus giganteus), called "suguaro" by the Mexicans. Leaving the Sierra de los Pajaritos the line crosses in succession the Baboquivari Valley, the Baboquivari Mountains, and the Moreno Flat. Although absolutely bare of trees and bushes, it is hard to picture a more beautiful valley than the Baboquivari, in the vicinity of Buenos Ayres, during the "rainy season." To the northwest towers the striking Baboquivari Peak, venerated by the Papagos as the abode of their God; in the foreground is a wide lake, while in every direction stretch gentle swells and hollows covered with magnificent grass and with a profusion of wild flowers. Thousands of cattle and horses find pasturage in this valley, and stock raising would be very profitable did this condition of things last; but the ranges here, as in all places along the border, are overstocked; the lake dries up in the spring, and water has to be pumped from bored wells several hundred feet deep. This valley marks the eastern limit of the region along the boundary reached by the summer UNITED STATES AND MEXICAN BOUNDARY. 21 "sea breezes" from the Gulf of California, which here were constant and refreshing. In the hills at the south end of the valley and a short distance below the line, is situated the Mexican custom house of Sasabe, while at Buenos Ayres, about 6 miles north of the line, is located the United States custom-house. At the foot of the Babo(iuivari Mountains (here called the Pozo ^'erde Mountains), a little over a mile south of the line, is located the Papago Rancberia of Pozo Verde, named from a hue spring in the vicinity, which is the only natural water, except that in the Sonoyta Valley, until the Colorado Kiver — 200 miles distant — is reached. This rancberia consists of about 35 adobe huts, and contains a population of about 150 persons, who own several hundred head of cattle and horses. Au excellent road leads from Tucson, via Buenos Ayres, La Osa, and the south end of the Pozo Verde Mountains, to Pozo Verde, while another and shorter road on the west side of the Baboquivari Mountains leads from Tucson, via La Ventana, to the same [dace. The broad valley west of the Baboquivari Mountains is called the Moreno Flat, from a mouutaiu of the same name on its west slope. The soil of this valley is very fertile and supjiorts a fine growth of mesquite. In seasons of normal rainfall the grazing is excellent, but as little rain had fallen during the loug drought preceding the survey, scarcely a blade of grass could be seen, while the surface of the entire flat was cut up by innumerable cattle tracks, leaving the soil loose and powdery for a depth of 2 or .'5 inches. In this valley, on July 3, 1893, was encountered a sand storm of frightful violence. About 4 o'clock in the afternoon a dense, dark-brown cloud was seeu rising in the south, which presented a singularly threatening appearance. The sun, which until then had been shining brightly, was soon overcast, and in a few minutes after the cloud was first noticed the storm burst in all its fury, filling the atmosphere to a height of several hundred feet with the loose soil of the valley. In ten or fifteen minutes after the storm burst it became as black as midnight, respiration was almost impossible, and it was only by breathing through a handkerchief held in front of the mouth that suftbcatiou was avoided. In about half an hour the wind began to subside and the darkness to diminish, and finally, in a little over two hours after the storm commenced, the setting sun shone faintly through the particles of dust which still filled the air. Many sand storms were encountered during the progress of the work, but none so appalling as this in its suddenness, violence, and darkness, and uone so remarkable for the brevity of its duration. A few miles northeast of the Moreno Mountain, in the center of the valley, has recently been located a large cattle ranch, called La Ventana, at which a good supply of slightly alkaline water is pumped from two artesian wells, between eight and nine hundred feet deep. This ranch is the last white settlement in the United States near the boundary until the Colorado Eiver Valley is reached. From the Moreno Flat the line passes over a low saddle in the mountain of the same name, thence over the mesquite-covered flat northeast of the Cobota Eange, passing but a few yards north of the low, rocky, vertical escarpment which marks the most northernly point of this range. The flat terminates at the Lesna Mountains, a jagged trap-like range, composed principally of porphyry, and forming a spur of the Cobota Mountains. This range is bordered on both sides for a width of several miles by a luxuriant growth of mesquite, palo verde, palo fierro, and cactus. At the point where the line crosses is a remarkable peak, called Cerro de la Lesna, having vertical sides and two horn-like prominences, over the north one of which the line passes. About 6 miles southeast of this peak is the Papago Eancheria of Cobota, plentifully supplied with water from a shallow well. About 2 miles west of Cobota is a Yaqui and Papago liancheria, called Pozo de Luis (and also El Vauori), situated at the west entrance of the pass through the Cobota Mountains. At these rancherias were seen large herds of cattle and horses, ail in excellent condition, and the former superior to any others seen on the survey. The water at Pozo de Luis is the last encountered until Sonoyta, distant 50 miles by wagon road, is reached. About 2 miles north of Cerro de la Lesna a few "renegade'' Papagos, called "Los Coches," were located at a well which is reputed to yield a very unreliable supply of water. These Indians were fugitives from Mexican justice, having been outlawed for their numerous crimes. They were 22 UNITE]! STATES AND MEXICAN BOUNDARY. iinicli dreaded by tbe few travelers tbrough tbis regioii, but failed to sustaiu tbeir reputatiou, for ou approacb of tbe working parties tbey abandoned tbeir raucberia witb all its contents and did not return until tbe survey bad progressed many miles beyond. Tbe country along tbe boundary on botb sides of tbe line between tue Baboquivari Mountains and tbe Sierra de las Tinajas Altas forms a part of tbe Papagueria, a region probably as little traveled and as little known by wbite men as any in our country. Tbe Papagueria, as indicated by its name, is settled almost exclusively by tbe Papagos, a tribe wbicb numbers several tbousand persons, only about one-balf of wbom reside witbin tbe limits of tbe United States. Tbis entire region is a hopeless desert, on wbicb none T)ut these hardy Indians could tind subsistence. At tbe few permanent wells and springs are located tbeir rancberias, from wbicb, as soon as the July rains begin, they scatter over the Papagueria to their numerous " temporales." These "temporales" are located near some natural or artificial water hole, from which their supply of drinking water is obtained, and are in close proximity to cultivable lands. Tbe bouses are generally built of adobe, and tbe fields protected by rude fences of mesquite brush. In tbe "temporales," so deserted and forlorn during most of the year, a wonderful change takes place witbin a day or two after the first rain of summer. Where before all was desertion and silence all is now life and activity. Cattle and horses are being driven to pasture; bouses and fences repaired; Indian corn, beans, pumpkins, and melons planted, dams repaired, and shallow irrigation ditches cleaned out. Ill many cases the natural rainfall alone is relied upon and no recourse is had to artificial water boles or ditches. Owing to the fertility of tbe fields and tbe beat of tbe climate the crops mature rapidly, and in three or four months the " temporales" are again silent and deserted. Occasionally, when the winter rainfall is unusually great, crops of wheat are also grown at the "temporales." During June and July the food supply is greatly augmented by the fruit of the giant cactus, which ripens then, and which is gathered in great quantities by tbe squaws. Some of it is eaten fresh; some dried for winter use; some boiled into preserves; from some a beautiful carmine sirup is made, and not a little is consumed iu tbe manufacture of a slightly intoxicating fermented drink. Another drink, nonintoxicating and very refreshing, is made from a minute, gum-coated seed called "chilla," which partly dissolves when placed in water. Every year the Papagos make long excursions to the mountains to gather acorns for food, and in times of scarcity tbey make great use of mesquite beans and seeds of certain grasses. They are an intelligent tribe, peaceably disposed both toward the United States and Mexico, but possessing an undying hatred for their old enemies, tbe Apaches. The men are well armed and are skillful hunters, and the young squaws far above tbe average in good looks. Like the Yumas, Oo-co-pabs and Diegenos, the Papagos proved tborouglily honest as far as tbis expedition was concerned, not a single piece of property and not an article of food having been stolen, and this, too, notwithstanding tbe fact that throughout the Papagm'-ria, owing to the great scarcity of water, the escort was always camped many miles from the working parties. Tbe Papagos look witb longing for the coming of "Moctezuma," their promised Messiah, who is to right alJ wrongs and to make the arid desert a garden and his people greater than all others. Except in tbe vicinity of civilization, their bouses are built with tbe doois facing the east, so that when Moctezuma comes with the rising sun be may find all doors open for him. Leaving Cerro de La Lesua the line crosses a broad, mesquite covered flat, about IS miles in width, and then passes in succession over tbe east branch of tbe Sierra de la Nariz, the Santa Kosa Valley, in which is located a " temporal " of tbe same name, and the west branch of the Sierra de la Nariz. Tins range is a spur of the Sierra del Ajo on the north, and is a bare, rugged mass of igneous rocks overlaid with a capping of broken black lava, which gives it a most dreary and somber aspect. On the east branch of the range just north of the line is a most interesting and elaborate system of fortifications, formed of walls of lava about waist high and 2 or 3 feet in thickness, excellently located for defending the crest against assault. These fortifications were said to have been constructed by tbe Papagos for defense against Mexican troops when tbe region belonged to Mexico; but this is a mere tradition, which could not be verified. At the south end of tbe east branch of tbe Sierra de la Nariz is located the Nariz Temi)oral, a little south of tbe road from Altar to Sonoyta. UNITED STATES ANU MEXICAN BOL-NDAKY. 23 After leaving the Sierra de la Nariz the line passes over a valley about 12 ujiles wide and then crosses the Sierra de Sonoyta, at the end of which flows the Sonoyta Elver, a stream about 12 feet wide and 6 or 8 inches deep. Sonoyta was formerly quite a flourishing little agricultaral village, but heavy rains caused the river bed to sink so deep below the level of the surrounding lands that irrigation was attended with many difliculties, and by a lamentable want of energy and united action in constructing a dam to raise the level of the water the village fell into decay, family after family moving away, until now scarce a half dozen Mexican families remain, while abandoned fields and magnificent fig trees, dying for want of water, are painful reminders of past prosperity. About 8 miles west of Sonoyta is situated the Mexican custom-house at Santo Domingo, on the ranch of Don Cipriauo Ortega, who cultivates about 300 acres of land, the largest area under cultivation by one person near the entire boundary. About 6 miles west of Sonoyta is the little settlement of Quitobaquita, near some fine springs, which burst out of the hills on the United States side of the line, but serve to irrigate a field near the river, on the Mexican .side. Two families of Mexicans reside here, but the houses near the springs all lie within the limits of the United States. The valley of the Sonoyta is quite fertile and must at one time or another, as shown from evidences now remaining, have been almost all under cultivation. The Sonoyta Eiver drains a very large basin, embracing almost the entire country between the Cobota Mountains and its actual source, a mile or so east of Sonoyta. For a short distance it continues as a running stream, then disappears, reappearing in the vicinity of Santo Domingo. Beyond this point it reappears, as a succession of shallow pools only, in two places, Agua Dulce and Agua Salada, the character of the water at each place being indicated by its name. Agua Salada is about 11 miles south of west of Quitoba((uita. With the exception of the Mexican families located at the settlement before mentioned the other inhabitants of the Sonoyta Valley consist of Papago Indians, who engage in agriculture and placer mining, liich gold mines have been located in the vicinity of San Antonio, about 30 miles south of the line, but the absence of water renders it extremely difiicult and expensive to develop them. About the same distance southwest of Quitobaquita is the prominent Sierra Pinacate, near the foot of which are immense salt beds, at present almost inaccessible on account of the sandy roads and the absence of water. From (Juitobaquita good roads lead to Altar, Mexico (via the Xariz Temporal), Gila Bend, on the Southern Pacific Railway (via the old Ajo Mine), and Tucson, Ariz, (via Nariz Temporal, Pozo de Luis, and Cobota, uniting with the road from La Ventana to Tucson a few miles north of the former place). On all of these roads, however, there are stretches of from 40 to 50 miles without water, and a. journey on them should never be attempted in summer unless an ample supply of water is carried along. Probably nowhere ahing the boundary cioes the cactus growth attain such luxuriance as in the foothills of the Sonoyta Valley. The giant cactus here attains a height of 40 or 50 feet and forms perfect forests, if the word forest can iiroperly be applied to a collection of these strange, ungainly, helpless-looking objects, which seem at times to stretch out clumsy arms appealingly to the traveler, and which one can not see on its native desert without unconsciously associating it with the uncouth forms of vegetation peculiar to the Carboniferous Era. Another large and very striking cactus found in this vicinity is called "pitahaya'' by the Mexicans, who esteem it very highly for its most palatable fruit. It consists of a cluster of incurving stems, several inches in diameter and 10 or 15 feet in height, which are covered with coarse, hair-like spines. All the hills and mountaius iu this vicinity are covered with a thick growth of "cholla" cactus, the needle-like spines of which readily penetrated shoes, leggings, and clothing, and caused much pain and annoyance to the working parties. From the Sierra de Sonoyta the line runs along the north slope of the Sonoyta Valley and then passes over the barren, cactus-covered ridges which lie between the Quitobaquita Mountaius and the Cerro Salado and separate the Sonoyta Valley from the dreaded Tule Desert. When the surveying party was working in this vicinity during the month of June, 1893, the heat was intense, the maximum temperature in the shade reaching 118° F. and the mean maximum in the shade for the whole month of June averaging 110^ F. The standard thermometer used was not graduated sufficiently high to give the temperature in the sun after 8 or 9 o'clock a. m., at 24 UNITED STATES AND MEXICAN BOUNDARY. which time it ranged from 130° to 140° F. ; the temperature in the shade at this time generally ranging from 95° to 105° F.. a ratio which would seem to indicate an average maximum sunshine temperature during June of about 150° F. The temperature during June, 1893, must be considered, however, as in excess of the average, for a thermometer record kept at Sonoyta and covering a period of several years showed this to have been the hottest June during the period covered by the observations. At times the breeze which had swept over the scorching sands to the south was so hot as to wither vegetation and burn the skin as would the heat from a furnace, rendering it necessary, even when in the shade, to screen the face from its scorching heat. Leaving the divide north of the Oerro Salado the line strikes the Tule Desert, a wide, waterless area dotted with extinct volcanoes and numerous bare, isolated peaks of black or dark-brown igneous rocks, which but add to the loneliness and desolation of the scene. About tlie middle of this desert is a broad, low depression called "Las Playas,'' which is bordered by a fringe of mesquite and greasewood, and in which a few "charcos," or natural water holes, retain water for a short while after the occasional rains. West of this depression is a considerable area covered with lava from one of the extinct volcanoes in the vicinity. Near the road in this vicinity is the skeleton of a camel, which, the Mexican guide stated with much relish, had been brought for use on the deserts in northern Sonora and had perished here of thirst. Many miles to the south of the line the view is cut off by ridges of drifting sand, while to the north it is limited by jagged, rocky ranges, among the most prominent of which is the Sierra Pinta, a bare, rocky sierra, one-half of which is light gray while the other half is reddish brown. Between the Sonoyta A'alley and the Colorado Eiver the vegetation consists almost entirely of palo verde, palo fierro, mesquite, greasewood, and giant cactus, while the only grass seen is a tall, uninviting-looking species, called "galleta" by the Mexicans, which mules and horses ate with avidity and which is sufficiently plentiful, when one becomes familiar with the localities where it grows, to supply the place of hay, were it not for the fact that the scarcity of water ordinarily renders it impossible for travelers to delay long enough to permit their animals to graze. Leaving the Tule Desert the line crosses in succession the Sierra del Tule, the Lechuguilla Desert, the north end of the Sierra Lechuguilla, and the south end of the Sierra de las Tinajas Altas — the name by which this portion of the Gila Eange is known. The three sierras enumerated above present to the eye much the same general appearance, although dift'ering greatly from all other mountains encountered heretofore. They are bare, desolate, rough, and jagged to an unusual degree, and so steep that in many places it is impossible to climb to the summit, while in most places it is both arduous and dangerous; and when the jagged, knife-like crest is finally reached it often proves to be so narrow that it is impossible either to walk along it or set up an instrument there. All three of these ranges rise directly out of the surrounding desert and appear to be crests of mighty ranges whose foothills and lower slopes lie buried far beneath the drift and sand. The Sierra del Tule and the Sierra Lechuguilla are composed of a bewildering chaos of trachyte, porphyry, granitic rock, and lava, while the Sierra de las Tinajas Altas is composed of a coarse, grayish rock resembling granite, which appears at one time to have been washed by water, and as a consequence has been worn smooth and indented with numerous cavities similar to those found in rocks on the seashore. A few miles north of the boundary, in the Sierra del Tule, are several peaks of gray rock curiously capped with black trap or lava, one of which, called the Cerro de la Cabeza Prieta, is a very i)rominent landmark when crossing the Tule Desert. An extinct volcano, whose sides are curiously streaked with black lava, is situated on the west side of the Sierra del Tule, about 3 miles north of the wagon road, and the entire country south of this volcano is covered with a mass of broken, black lava. During the "early sixties" there was a large influx of Mexicans from Sonora to the gold diggings on the Colorado River, and an enterprising Mexican dug two wells near the road, in the Tule Mountains, built a small adobe house, and occupied it with his family for two years, for the purpose of selling water to travelers. But the deaths from thirst along this route became so frequent that the road was soon abandoned, and for over twenty years had remained unused. ■I%i UNITED STATES AND MEXICAN BOUNDARY. 25 Having accidentally learned of the former existence of these old wells, which are not shown on any maps, arrangements were made to have them cleaned ont as soon as possible. This was done by a party of Mexicans and Papagos fi'om Sonoyta, who found them almost tilled up., These important wells are situated on the road about 5 miles north of the point where the line crosses the summit of the Sierra del Tule, and when thoroughly cleaned out yield a supply of about 500 gallons per day. The water is beautifully clear, but owing to the presence of minerals has a vile taste and is very unwholesome. Near the wells stand the ruins of the old adobe house, the only building between Quitobaquita and the Colorado Eiver. About 6 miles northwest of these wells and about one-fourth of a mile east of the summit of the Cerro de la Cabeza Prieta, in a deep, rocky canon, are a number of natural tanks, worn in the rocks and filled by the rains. These tanks when full contain about 5,000 gallons of water, all of which is seldom exhausted, by evaporation alone, before another rain tills them. Tliese tanks are known as the "Tinajas del Cerro de la Cabeza Prieta," but were never much used by travelers, as they were off the road and could not be reached by vehicles. Many years ago the Papagos were accustomed to camp at these tinajas and the Tinajas Altas for the purpose of hunting "big horns" or mountain sheep, which then, as now, constituted the principal inhabitants of these desolate sierras. In the vicinity of the tanks are still seen the remains of their old camps, around which are strewn the horns of the mountain sheep — as many as twenty or thirty pairs having been counted at a single camp. This noble game is still plentiful in these mountains, fortunately protected by their ruggedness, their inaccessibility, the deserts which surround them, and tlie risk of death from thirst to which hunters would subject themselves. In the side of a natural, semicircular amphitheater on the east side of the Sierra de las Tinajas Altas, about 3.^ miles north of the boundary line, are the Tinajas Altas, a series of beautifully picturesque, natural tanks, worn in the solid rock by the waters of a narrow, rocky valley several hundred feet above, which, during the infrequent rains, come tumbling down the narrow gorge on the west side of the amphitheater and fill the tanks. These tanks hold about 15,000 or 20,000 gallons in all, when tilled. They consist of seven large ones and a number of small ones; but with the exception of the lowest tank, which can be approached by animals, they are very difficult of access. The next three are reached with difiSculty by climbing the steep, water-worn rocks on the left of the gorge, but the upper ones can only be reached by ascending, to a height of several hundred feet, the stee]) ravine on the right of the gorge. To render this water available for the uses of the survey it was siphoned from the upper tanks to the lower one by a suitable length of hose. The water, although sometimes covered with a green scum, is deliciously cool and palatable. Unless consumed by prospectors or smugglers, which is seldom the case, water can be found at all times in some of these tanks, as there is no loss from seepage, and as the steep, rocky surrounding and overhanging walls greatly retard evaporation ; to what extent is shown by the fact that on the reconnoissance from Yuma to Quitobaquita in the winter of 1893 these tanks were found nearly half full, although the rainfall at Yuma for the preceding twelve months had aggregated less than three-fourths of an inch, a remarkable deficiency even for this dry section. That this water supply was a very uncertain one when the road from Sonoyta to Yuma was much traveled (as was the case during the rush to California in " the tifties " and to the Colorado Eiver diggings in " the sixties") becomes painfully apparent from the number of graves, about fifty in all, on the bluff just east of the tanks. These graves, covered by stones laid on the ground in the form of a cross, mark the resting jjlace of thirsty travelers who had pushed on to the tanks, hoping to find water there; but disappointed in this, and too weak to journey on, had perished miserably of thirst; their sufferings aggravated in many cases by the knowledge that the water which they craved could be obtained in one of the tanks but a few yards above them, had they but strength to climb to it. Although these tanks are now but little known, few Americans having ever visited them, yet it is very interesting to note that they are shown on the map made by Father Kino, the Jesuit missionary, of the region around the Gila and the Gulf of California, as the result of his travels from 1698 to 1701. S. Doc. 21:7 G 26 UNITED STATES AND MEXICAN BOUNDARY. Two other tanks, of which do previous knowledge had been obtained, were discovered a short distance above the heads of the two valleys which indent the east side of tlie uionntains between 1 and 2 miles north of the boundary. These had each a capacity of about GOO or 800 gallons. The road from Sonoyta to Yuma passes by Agua Dulce, Agua Salada, Tule Wells, and the Tinajas Altas, from which point it keeps on the east side of the mountain range and parallel to it to the valley of the Gila, down the south side of which it passes until the town of Yuma is reached. In "the fifties" the road forked about a mile north of the Tinajas Altas, the west fork going- through the pass at this i)oint, and thence directly over the Yuma Desert to the town of Yuma. This part of the route, however, was soon abandoned on account of the heavy sand and the loss of life from thirst. The road between Agua Dulce and Yuma is for the most part very heavy, and, until the Tule Wells were reopened, no certain supply of water could be counted on between Agua Dulce and the Colorado Eiver. This road is appropriately called by the Mexicans " El camino del Diablo." When traveling it for the first time, alone or with but few companions, it is hard to imagine a more desolate or depressing ride. Mile after mile the journey stretches through this land of "silence, solitude, and sunshine," with little to distract the eye from the awful surrounding dreariness and desolation except the bleaching skeletons of horses and the painfully frequent crosses which mark the graves of those who perished of thirst — grim and suggestive reminders when the traveler's supply of water is running low. In a single day's ride sixty-five of these graves were counted by the roadside, one containing an entire family, whose horses gave out and who, unable to cross the scorching desert on foot, all perished together of thirst. Their bodies were found by some travelers during the following rainy season, and were all buried in one grave, which is covered with a cross of stones and surrounded with a large circle of stones, inside of which not a bush nor a blade of grass grows. Near by lie the skeletons of their horses and the broken fragments of their water bottles. During the few years that this road was much traveled, over 400 persons were said to have perished of thirst between Sonoyta and Yuma, a record probably without a parallel in North America. Leaving the Sierra de las Tinajas Altas the line crosses the Yuma Desert and descends into the valley of the Colorado, terminating at the point where it intersects the axis of the channel of that river. The name Y'uma Desert is applied to the entire country included between the Gila Eiver, the Gila Range, the Gulf of California, and the Colorado River, a region without water and covered for the most part with shifting sands and a scrubby growth of greasewood. I'arallel to the Gila Range and separated from it by a valley 4 or 5 miles in width is a range of hills which begins about a mile or two north of the line and extends northwest for a distance of 15 or 20 miles. About halfway across the desert the line crosses a ridge of drifting sand 2 or 3 miles in width and then a low, volcanic ridge which borders it on the west. Many miles to the south is seen a perfect sea of sand out of which rise jagged, isolated peaks and extinct volcanoes. Every- where else is an endless succession of sandy swells and hollows sloping gradually down to the Colorado River. Descending abruptly from the desert the line passes over the fertile valley of the Colorado and terminates in the channel of that stream. Section 5, Colorado River. — The Colorado, like the Rio Grande, is a variable stream, carrying an immense amount of sediment, and is generally navigable by light-draft steamers throughout the year for several hundred miles above its mouth. The river floods in June, during which time great changes of channel take place in those reaches, which, like the boundary section, are bordered by alluvial banks. The river valley along this section is many miles in width and is covered with a dense growth of mesquite, cottonwood, willow, arrowwood, (juelite, and wild hemp. The soil is exceedingly fertile from the frequent inundations, and would doubtless produce fine crops. The Colorado Eiver along the boundary is peculiar in that its course does not follow the lowest depression between the Gila Range and the Coast Range, but lies some 50 or 60 miles east of this depression, and at an elevation of over a hundred feet above it. Nor does it seem, as is sometimes contended, that this elevation is due entirely to the constant deposition of sediment along its banks and the consequent elevation of its bed, for tlie profile along the boundary over UNITED STATES AND MEXICAN BOUNDARY. 27 the Colorado Desert, west of Yuma, shows the same gradual and uniform downward slope, until the depression at Salton River is reached, and on this desert no alluvial sediment appears ever to have been deposited either in recent or past ages. Moreover, in slope, elevation, and composition, this desert appears but a continuation of that on the east side of the valley. This river is also remarkable for the very high tides at its mouth, and for the "bores" which at certain phases of the moon come rushing up the tidal portion of the stream, threatening with destruction all small craft encountered. At the junction of the Gila and Colorado is located the Jiourisliing little town of Yuma, which before the advent of the Southern Pacific Eailway furnished supplies for almost all of Arizona and Xew Mexico. The town still supplies the mining camps on the Colorado Eiver and its vicinity, and has become quite a resort for persons afflicted with pulmonarj^ troubles. Extensive projects for irrigating and cultivating the fertile lands of the Colorado River Valley and vicinity are now being promoted, but up to the present time practically none of this land is cultivated, except by Indians. The river valley from Y'uma to the gulf is inhabited only by Yuma, Co-co-pah, and Diegeno Indians, peaceable and light-hearted people, fond of games, excellent swimmers, and delighting, like all savages, in painting their faces and bodies. The men are noticeable for their splendid physique, but the women are generally fat and unattractive in appearance. As a rule they possess no firearms, and on the lower reaches of the river may yet be seen hunting with the bow and arrow. They still cremate their dead, frequently burning at the same time the rude hut and personal effects of the deceased. Section 6, azimuth line from the Colorado Firer to the Pacific Ocean. — Starting at the Colorado River, the line x^asses for about two-thirds of a mile over the fertile river valley, then rises to the water-washed mesa southeast of Pilot Knob, a prominent, isolated mountain about a mile north of the line. Over this mesa the line passes for about 3 miles, when it encoianters several high ridges of drifting sand, all of which it crosses in a distance of about 4 miles. From the sand hills to Salton Eiver, a distance of about 27 miles, the line passes over a flat desert, similar in ai^peai'ance and vegetation to the Y'uma Desert, and forming a part of the Colorado Desert, the name which is applied to the entire country included between the mountains north of the Southern Pacific Railway, the Colorado River, the Gulf of California, and the Coast Range. From Salton River to a point a little over a mile east of the north spur of Signal Moun- tain, a distance of about 21 miles, the line passes over an alluvial depression, a considerable portion of which is covered at intervals of several years by the overflow from the Salton and i^ew rivers, as was the case in the summer of 1891, when their overflow filled the dry bed of the Salton Sea, and for a time threatened to submerge the tracks of the Southern Pacific Railway in this vicinity. To understand the nature and cause of these overflows it is necessary to describe somewhat in detail the topography of this region for a considerable distance on both sides of the boundary line. About 5 miles below the boundary the Rio Padrones, a branch of the Colorado, ordinarily about 75 feet in width, and having a very swift current, separates from the main stream and flows in a generally southwest direction, emptying into a lake several miles in length, called Jululu Lake. This lake lies some 15 or 20 miles south of tlie boundary line, and near its west shore are the famous mud volcanoes of the Colorado Desert, while a short distance west of these loom up the bare, rocky ridges of the Co-co-pah Mountains. The outlet of this lake, known as Hardys River, flows in a generally southeast direction, and unites with the Colorado some 20 miles above its mouth. The area included between the Colorado and these western branches is intersected by numer- ous " blind channels," which are all filled when the Colorado overflows. At times of extraordinarily high water in that river another channel, which branches from the Colorado in the same locality as does the Rio Padrones, becomes filled, and under the name of Salton River flows west for about 30 miles, then northwest for about 50 miles, antl empties into the depression called Salton Sea. At the same time Jululu Lake becomes so filled from the over- flow that a portion of its waters seeks an outlet by a channel called Xew Eiver, which flows in a northwest direction for about GO miles, and also empties into Salton Sea. When the flood in the Colorado subsides these streams cease to flow, aud their courses are marked by a succession of 28 UNITED STATES AND MEXICAN BOUNDARY. lagoons remaining in the deep channels which their waters have cut in the alluvial soil. Exposed to the dry atmosphere of the desert, these lagoons soon evaporate, and for years at a time not a drop of water can be found along their courses. Ordinarily the height and duration of the flood in the Colorado barely suffices to fill Salton and New rivers for a short distance from their sources, and it is only at long intervals that any part of the waters of these streams reaches Salton Sea. This, however, occurred in 1801, when not only were these rivers tilled, but so great was the volume of water poured into them that they in turn overflowed their banks and submerged much of the surrounding country, the overflow of the two rivers, which in the limits of the United States are approximately parallel to one another, in some cases uniting. The channels of these streams are fringed with a thick growth of mesquite, while the limits of overflow are plainly marked by a most luxuriant growth of an Amaranthus (called "quelite" by the Mexicans), a plant much esteemed as food for cattle. The growth of qnelite, mesquite, and grass following the overflow of 1891 furnished fine pasturage for several thousand head of cattle brought here from the overstocked ranges of Arizona and California. The entire area between the head of Salton Sea and the Gulf of California once undoubtedly formed a part of this gulf, from which in comparatively recent geological times its waters were separated by some process still somewhat obscure. By many it is believed that this separation was effected by an elevation or upheaval in the region between the boundary line and the present head of the gulf. While admitting that this theory is perfectly plausible and quite possibly correct, j'et from the present condition of things it seems more probable that this separation was effected by the deposition of sediment from the Colorado liiver, aided perhaps by the action of the winds and tides on this sediment. From the configuration of the surrounding country it would ap])ear that before this separation occurred the Colorado lliver must have flowed into the gulf on its east shore about 75 or 100 miles below its then head and at a point where the gulf must have been quite narrow, limited as it was by a spur of the Co-co-pah Mountains on the west and by the Yuma Desert on the east. When we consider the immense amount of sediment brought down by the waters of the Colorado, and the further fact that rivers emptying into the sea invariably discharge their waters at right angles to the shore line, in this case directly across the narrow gulf, it does not seem improbable that in time this sediment would separate the waters above the mouth of the river from those below. If this theory is correct, the original bottom of the gulf would be found only in the vicinity of Salton Sea, which is about 250 or 275 feet below mean sea level, while from that point to Jululu Lake would be found a gradually increasing thickness of sedimentary deposit from the overflows, first, of the Colorado and afterwards of Salton and New rivers. To the north of Salton Sea the old beach line is easily traced, and its elevation differs but little, if any, from that of the Pacific, showing that if any elevation or dei)ression has occurred elsewhere, this locality at least has been practically unaffected thereby. Salton and New rivers present the anomalous condition of two streams parallel to one another, and to the axis of lowest dep^-ession in their vicinity, the first being about 18 and the second about 8 miles east of this axis, as measured along the boundary. The corresponding elevations of the surface at each point being +20', — 7', and — KJ' respectively, referred to mean sea level; the last marking the lowest point along the entire boundary line. About 4 miles west of this ]ioint the line crosses the foot of the north spur of Signal Mountain, a iiromineut peak marking the north end of the Co-co-pah Eange, and visible from all points of the Colorado Desert. For about 10 miles the line passes over a bare, rocky, water-washed mesa, about 300 feet above sea level, from which, by a succession of three or four terraces, indescribably bare, jagged, rough, and precipitous, the line, in a distance of about 11 miles attains the summit of the Coast Range at an elevation of about 4,500 feet. This range acts as an effectual barrier in shutting off from the Colorado Desert the moisture- laden winds of the Pacific. This action was beautifully shown in March, 1893, when for three days it had been raining almost continually over the entire country west of tlie summit, several inches of rain having fallen in that time. Daring this entire period a gale from tlie coast was UNITED STATES AND MEXICAN BOUNDARY. 29 driving a continual mass of dark rain clouds over the crest of the Coast Range, where at the time it was alternately raining and snowing. Encountering the hot air rising from the desert these clouds rapidly began to dissipate, and finally disappeared entirely about 10 miles east of the summit, appearing when viewed from below like a vast cloud of steam exhausted into air. Between the Co-co-pah Mountains and the Coast Range, and about 10 or 15 miles south of the boundary, is a large salt lake, called Lake Maquata by the Indians, and about 9 miles east of the summit of the Coast Range and about 5 miles south of the boundary, in the mouth of a large caiion, is a small stream of pure mountain water. During the years when New and Salton rivers remain dry no water is found near the boundary line between the valley of the Colorado River and Coyote Well, a very shallow well of wretched- tasting water, about 8 miles north of the boundary and about 12 miles east of the summit' of the Coast Range. The entire Colorado Desert is subject to frequent sand storms and constant and violent winds prevail along the foot of the Coast Range. The summer heat is fearful; the highest temperature ever recorded at any Weather Bureau Station in the United States, 128° F. in the shade, having been obtained in July, 1S87, at IMammoth Tank, a station on this desert about 25 miles north of the boundary. Although far less traveled than before the advent of the railroad, the desert continues to claim its victims, over half a dozen persons having perished of thirst on it during the past two years. From the summit of the Coast Range to the Pacific, settlements become more frequent; the country is better known, and the maps more accurate; consequently less detail is necessary in describing it. The descent from the summit to the Pacific is far more gradual than that to the Colorado Desert and the entire character of the vegetation undergoes an abrupt change; the mountains being covered with a dense growth of brush, while the valleys are dotted with beautiful evergreen oaks. Leaving the summit of the Coast Range, the line crosses the Jacumba Valley and the broken country west of it, and passes just to the south of Round Mountain; thence it crosses succes- sively the rocky ridges west of Round Mountain, Milquata Valley, another succession of ridges, Tecate Valley, and Mount Tecate, passing over the south slope of this mountain at an elevation of about 3,400 feet. Leaving Mount Tecate, the line crosses Cottonwood Creek, the south slope of Otay Mountain, at an elevation of a little less than 1,700 feet, Otay mesa, Tijuana River, and the high, flat ridges in the vicinity of the ocean. For many years previous to the completion of the Southern Pacific Railway a stage line had been maintained between Yuma and San Diego; wells had been sunk in many places on the desert, and stage stations established in their vicinity. At the time of the survey this road had remained untraveled for years; the wells had all filled up; the station houses were but ruins, and all traces of the old road were in many places obliterated for miles at a stretch. Although still known by their old names, the stations now afford neither a permanent water supply nor shelter. The road used on the survey followed the old stage route along the Colorado and Salton River valleys, via Hanlons, Cooks AVells, and Seven Wells, until Gardners Station was reached. From this point to JSTew River station the old road had been washed out by the overflow of 1891, and consequently it was necessary to continue down the Salton River Valley for several miles and then ascend to the sandy desert on the north, on which the road continued for a few miles, descending into Saltou River Valley and crossing the dry bed of that river about a mile below the boundary. From this point the road continues to Indian Wells, crossing the boundary line about 3 miles east of New River, and uniting with the old stage road a short distance east of Indian Wells just after crossing the dry bed of New River. From Indian Wells to San Diego the road follows the old stage route, via Laguna Station, Coyote Well, Mountain Spring, Jacumba, Campo, Potrero, and Dul/Ai-a. Between Cooks Wells and the point where it crosses Salton River the road is very heavy. Just before reaching Mountain Spring Canon a stretch of very heavy sand is encountered, which continues up to the mouth of the cafion. The road through the caiion is rough beyond description, and although but 3 miles in length, caused more damage to vehicles than did any other road on the entire survey. 30 UNITED STATES AND MEXICAN BOUNDARY. Witli these exceptions, tlie road is fair for the entire distance from Salton Eiver to San Diego. It must be borne in mind, however, that between the Colorado River and Jacumba Valley there is ordinarily not a blade of grass, while often for months at a time not a drop of water can be found between the Indian village, a few miles east of Cooks Wells, and Coyote Wells, a distance of 80 miles by road. Twelve miles beyond Coyote Wells is Mountain Spring, attbrding a good supply of excellent water. The next water, a bold sulphur spring, is found about 8 miles farther, at Jacumba, the first settlement encountered after leaving the valley of the Colorado River. From this point to the Pacific, water is sufScieutly plentiful to render a detailed description of its location unnecessary. To persons unfamiliar with the deserts of the Southwest, it will doubtless appear that undue prominence has been given to the question of water in the preceding description of the country along the boundary, and in refutation of this idea it is necessary to call attention to the fact that supplying, the working parties with water on the deserts was the problem of the survey, in comparison with which all other obstacles sank into insignificance. To the traveler on the desert the all-important questions are: The distance to the next w-ater, the nature of the supply, and the character of the intervening roads. For while he may be able to live without food for several days, he knows that, exposed to the scorching heat of summer, men drinking their fill at sunrise frequently become crazed and in some cases perish of thirst before sunset. Nor must it be forgotten that at such times so profuse is perspiration and so rapid its evapora- tion that the quantity of water consumed by men and animals is very large, averaging at one period of the survey about 7 quarts per day for the men and 20 gallons for the animals. On the desert the mirage continually mocks the traveler with deceptions apparently so real that it is difiQcult to persuade liim that what he sees is a mere atmospheric freak and has no actual existence. Just before sunrise craggy peaks are seen, capped by similar, inverted peaks, which gradually become flatter and flatter, frequently stretching out like great arms from the summit and uniting •with those from neighboring peaks. Once a city with all its buildings appeared in a valley many miles to the north, but the morning sun (juickly resolved it into a number of large bowlders, near the foot of a craggy mountain. At another time, on the flat, bare Yuma Desert, the reconnoissance party seemed to be in a level depression, surrounded on every side by a vertical, palisade-like wall of solid rock, 50 or 100 feet in iieight, which moved with them as they journeyed toward the river, but gradually diminished in height until it finally disappeared. The most common deception, however, is seen in the heat of the day, when beautiful, quiet lakes and timber-fringed ponds lie in tantalizing attractiveness, apparently but a few hundred yards away, the details so perfect that the reflection of every object on the bank is faithfully reproduced, audit is little wonder that thirsty travelers unaccustomed to this mirage are lured from the road to procure this water, which ever appears but a little distance ahead, yet is never reached. It was also in the heat of the day that distortions of the size and form of animals generally occurred; as in one case where a band of wild horses was mistaken for a herd of antelope, and followed for several miles as such before the mistake was discoveied; and in another, where a coyote was mistaken for the same animal. At times a jack rabbit would loom up on the desert with the apparent size of a cow, while occasionally the legs of animals would be so comically lengthened as to give them the appearance of being mounted on stilts many feet in height. BECONNOISSANCES. Owing to the fact that a considerable portion of the country lying along the international boundary is of a character little calculated to invite travel by white persons, it was impossible to secure in advance reliable information concerning water, roads, and the general topographical features of the country, which information was essential to a proper prosecution of the survey. To obtain this information mounted reconuoissances were made from time to time as required by the progress of the work. With the exception of a reconnoissance of about 100 miles made by Mr. J. L. Tan Ornum, assistant engineer in charge of the topographic party (who also formed one of the reconnoissance UNITED STATES AND MEXICAN BOUNDARY. 31 party on three other occasions when the aggregate distance covered was about 700 miles), these reconuoissances were made by Lieut. D. D. Gaillard, United States Corps of Engineers, with a party comprising from two to five persons in all. . Pack mules were used to carry supplies whenever the character of the couiitry was such as to render the use of a spring wagon impracticable. The total distance covered on the recounoissances was 2,134 miles — 2,008 miles on horseback and 126 miles on foot. The time occupied in making a single reconnoissance varied from one to fourteen days, and the corresponding distances from 24 to 413 miles. The usual discomforts incident to such exiieditions were experienced and were aggravated, in the case of recounoissances on the desert, by the intense heat and the scarcity and poor quality of the drinking water. On a reconnoissance of 301 miles, made June 2-11, 1893, the maximum thermometer reading in the shade each day varied from 105° to 118° F. The discomfort of the trip was further increased by the ftict that the first four watering places were 45, 40, and 50 miles apart, respectively. In many cases there was little or no grazing for the animals, and as it was impossible to pack enough hay to last them for the entire trip they had to be fed principally on barley, and were often without water for considerable periods — on one occasion for a period of forty hours. Yet in spite of privations it is pleasant to be able to record the fact that not a man nor an animal was injured or disabled on any of these expeditions. CHAPTER III. ASTRONOMY. On the organization of the International Boundary Commission at Juarez, Mexico, November 17, 1801, the members of the Mexican section were present with a full outfit of instruments and observers ready for work. These instruments had been purchased by the Mexican Government at the date of the first convention in 1SS2, and were used by them to determine the latitude and longitude of Juarez at that time while waiting for the United States Government to appoint a commission. The United States commissioners having reached El Paso without instruments, men, or transportation, it was necessary for them to return north to organize their party, engage assistants, procure instruments, and purchase animals, wagons, and camp equipage before they would be able to begin field operations. The time between December 1, 1891, and January 20, 1892, was spent in securing assistants and in organizing the transportation for the field parties. Instruments used. — The question of the proper instruments to use for the observations of latitude, azimuth, time, and magnetics received careful consideration. The time was too limited to have new zenith telescopes of improved ijatteru constructed, and as the old Wurdemanns used in the survey of the northwestern boundary in 1872-1876 were stored at the engineer depot at Willets Point, N. Y., a requisition was made for the following astronomical instruments in addition to barometers, surveyors' transits, etc., for the topographical work of the survey: Two Wurdemann zenith telescopes, Nos. 18 and 20; two sextants and artificial horizons; two mean time chronometers; two sidereal chronometers. The two zenith telescopes were completely overhauled and were partially reconstructed by Fauth & Co., of Washington. In the field operations but one of them was actually used, the other being held in reserve. Each was furnished with spare level-tubes in case of accident to those attached to the instruments. For azimuth observations a 10-inch repeating theodolite, reading to 5 seconds on horizontal limb, was made by Fauth & Co., having an eyepiece micrometer and high standards for supporting the telescope, enabling the telescope to be " transited through " for reversal instead of being lifted from the wyes. This instrument was used for azimuth observations, using the liiethod of measuring by micrometer the angles between the star near elongation and the mark. The high standards, constructed of aluminum, were of great service in the field iu running lines on the ground, while 32 UNITED STATES? AND MEXICAN BOUNDARY. the micrometer in the eye end, together with the use of signals by heliotrope, facilitated the placing of the forwai'd signal quickly in line with the back signal. Micrometer readings on both back and forward signals afterward determined the small correction to be applied to the place of the forward signal. Two direction theodolites of 8-iucli limbs reading by two micrometer microscopes to single seconds were purchased from Fauth & Co., in January, 1803, and were used in measuring the angles of the triangulations made at Nogales and Yuma. These theodolites were made with low standards and telescopes of high power. One 8-inch repeating theodolite or altazimuth was borrowed from the United States Coast and Geodetic Survey for the magnetic observations, and was used along the parallels of 31" 47' and 31° 20', after which it was returned, at the request of the Superintendent, to the Coast Survey office, being needed in Alaska. This instrument was wholly of bronze and brass, no steel or iron being used. The telescope was fitted with an eyepiece micrometer and could be used for latitude observations instead of a zenith telescope, and it carried above the telescope a box containing a 6-inch needle for measuring the magnetic declination. The sextants and artificial horizons were used for time observations. Observations of the sun's altitude were made in forenoon and afternoon, and the resulting errors of chronometers were sufficiently accurate for use in latitude and azimuth observations. The four chronometers were put in complete order by Negus & Co., of New York. For trans- portation each chronometer was inclosed in a leather case, and two of these cases were then inclosed in a well-padded wooden box. This box was then inclosed in an outer wooden box having a false inside cover and bottom, backed by a system of spiral springs to deaden jars. The chronometers were kept in these double boxes from the time of leaving New York to the end of the work at San Diego, except the chronometers used for astronomical observations, which were immediately returned to the boxes after the observations were finished. This method of packing the chronometers was very satisfactory in its results, no injury to any chronometer having occurred, although transported many hundred miles over a very rough country with no roads, and the temperature of the chronometers changed very slowly, although the usual viiriation in the outside temperature during the twenty-four hours was from 50° to 70°. For a detailed description of all these instruments see report of John F. Hayford, assistant astronomer. Zenith telescope No. 20 was used for all the latitude observations and No. IS held in reserve in case of accident to the former. The mounting of the zenith telescope and theodolite under one cover, so as to combine stability of foundation with portability, was the subject of considerable study and experiment. An observ- atory of some sort was required, and it needed a floor. This observatory must be used also as an office for the astronomical party during the day in which to do the necessary computing and writing, none of our tents being large enough for this purpose. The whole must be portable and composed of parts small enough to load readily on a wagon. Both the zenith telescope used for latitude and the theodolite used for azimuth observations were mounted on hollow, triangular wooden piers 5 feet long, hooped with iron, painted, and sunk like fence posts, after which the triangular inside was filled with earth well rammed. A floor of boards, 9 by 12 feet, made in six sections and to fit around the wooden piers, supported only at the four corners, was laid, on which was erected a tent in the form of a " lean-to shed," with roof sloping toward the north, and o])enings the whole length of the roof over each instrument. The sides and roof of the tent were suijported and stiffened by a framework of wood and held in place by rope guys at corners and sides. The hollow wooden piers were very satisfactory and proved as firm as masonry. At Nogales and Yuma the zenith telescope was mounted on the brick piers used by the United States Coast and Geodetic Survey longitude party, and at those places the observatories were of wood. A comparison of the results obtained at these stations with those where the wooden piers and tent were used were all in favor of the latter. The instrument changed less in level during the night when mounted on the wooden pier, and the temperature inside the tent was more nearly the same as the outside air. The usual difference was 1° C. only, which rendered the stars observed very steady. UNITED STATES AND MEXICAN BOUNDAEY. 33 LONGITT'DES. The original plan agreed on by the joint commission for running the boundary was to determine both the latitude and longitude of the extremities and turning points of the boundary, at or near which points the monuments erected by Emory were reported as still standing, and to observe for latitude and azimuth on the parallels at points about 20 miles apart. Dr. T. (J. Mendenhall, Superintendent United States Coast and Geodetic Survey, at the request of the State Department, detailed a party to determine the longitude of five points, viz: El Paso, the monument at the intersection of parallel 31° 47' with the meridian, Kogales, Yuma, and old Monument Xo. 1 on the Pacific, near San Diego. The field work was completed between January and June, 1892. The method used was exchange of signals by telegraph. Usually ten nights' exchanges were obtained, five with one observer at eastern station and the other at western, then five more with the positions of the observers reversed. The same stars were observed at both stations for time and instriimental con-ection to eliminate errors in the right ascensions of the stars used. Assistants 0. H. Sinclair and G. li. Putnam had charge of the longitude parties, and the field expenses of both parties were paid by the United States section of the Boundary Commission, but no salaries to either officer. The longitude of Monument No. 1, where the parallel of 31° 47' leaves the Eio Grande, was fixed by a triangulation connecting the monument with the longitude station at El Paso. The longitude of monument 40 at the intersection of parallel 31° 47' with meridian was obtained directly by using a temporary field telegraph line erected by direction of General Greeley, Chief Signal Officer, United States Army, connecting with the Western Union telegraph line at Separ, on the Southern Pacific Eailway. General Greeley also furnished operators at both ends. The line was very quickly and successfully erected under direction of Lieut. Prank Greene, signal officer. Department of Arizona, by a detachment from the Twenty-fourth Infantry under command of MaJ. .James N. Morgan, to whom we are indebted for the prompt and successful completion of the work. The longitude of Nogales was transferred to monument No. 127, at the intersection of parallel 31° 20' with the one hundred and eleventh meridian, as determined by Emory, by a triangulation connecting the monument with the longitude station at Nogales. The longitude of monument No. 204, 20 miles below Yuma, on the line connecting monument No. 127 with the initial point in the Colorado, was obtained from the observed longitude at Yuma by triangulation. The longitude of monument No. 207, where the line from the junction of the Gila and Colorado leaves the river, was obtained from the same triangulation. The longitude of monument No. 258, on the Pacific, was furnished by the Coast and Geodetic Survey, based on observations for longitude made at San Diego in 1892, connecting this point with the main chain of longitude stations on the Pacific Coast and reduced to the monument by Coast and Geodetic Survey triangulation. lleaults for difference of longitude by United States Coast and Geodetic Survey of points on Mexican boundary. SAN DIEGO, CITY PARK, CAL., AND TUIIA, GOVERNMENT RESERVATION, ARIZ. Date. A K p. 10 09. 162 .095 .087 .100 .130 .144 :: .112 .130 .152 I March 16 1892 Observers change stations : March 24 ISS' March 26 1892 Weighted mean. 10" 09.H4'±O.UU5-. Transmission or vrai'e and armature time = 0.032- ±0.002'. Personal equation between C. H. Sinclair and G. R. Putnam, S — P = +0.192>±0.0M-. 34 UNITED STATES AND MEXICAN BOUNDARY. Results for difference of longitude iy United States Coast and Geodetic Survey of points on Mexican feoMndary— Continued. YUMA, GOVERNMENT RESERVATION, ARIZ., AND NOGALES, IN REAR OF CtTSTOil-HOUSE, ARIZ. April 13, 1892 April 14, 1892 Aprill5,1892 April 16. 1892 April 17, 1892 Observers change April 19, 1892 April 20, 1892 April 21, 1892 April 22, 1892 Apra23,1892 Weighted TransmiBSion or wave and ar Personal equation between C 14" 43.690- ±0.007'. wave and armature time = 0.045'±0.003'. Sinclair and G. R. Putnam NOGALES, IN REAR OF CUSTOMHOUSE, ARIZ., AND EL : +0.150- ±0.005'. IN UNITED STATES RESERVATION, TEX. April 29, 1892 April 30, 1892 May 1,1892 May 2,1892 May 4,1892 Observers change stations : May 6,1892 May 7,1892 May 8,1892 May 9,1892 May 10,1892 "Weighted mean, 17" 48.520-±0.009'. Transmission or wave and armatare time^: 0.034'±0.001' Personal equation between C. H. Sinclair and G. R. Putnam, S — P = +0.126 ±0.004'. CORNER OF BOUNDARY, NEAR MONUMENT NO. 40, AND EL PASO, IN UNITED STATES RESERVATION, TEXAS Date. A A , p. May 14 1892 6 52. 642 .660 594 May 16 1892 Weighted mean, 6" 52.626' + .013'. Transmission or wave Applied personal equation, S — P= + 0.126- ± 0.08". Absolute longitudes of the several positions can only be given after the final adjustment of the general longitude system of the United States has been made; at present but a very few Hues are wanting to complete the longitude net. Approximately we have: Time. Longitude. h.m. ,. 7 05 57. 350 7 12 49.976 7 23 45.870 7 38 29. 560 106 29 20.25 108 12 29. 64 110 56 28. 05 114 37 23.40 Yuma UNITED STATES AND MEXICAN BOUNDARY. 35 Tlie probable error of any of these results may be taken as ±0.12^ or i 1.80". We also bave the resulting value for the supposed Wheeler station at El Paso: Time, 7'' 05'" 50.7127": longitude, 106O 29' 10.90". Longitude of pi-ominent points on boundary. Points. Longitude. o , „ 1 106 28 55. 11 Monument No. 1, Rio Grande 106 3139.03 108 12 29 67 110 56 34. 63 111 4 34.45 114 46 48. 64 114 43 54.31 117 7 31.89 MonumentXo 358 Pacific LATITUDES. All the observations for latitude were made with zenith telescope ^o. 20, by the method of micrometer measures of difference of zenith distance of pairs of stars near the zenith. The time for latitude and azimuth was obtained by sextant observations on the sun. As it -was necessary to have the results for latitude and azimuth for the use, of the tangent parties at each station without delay, and as no one catalogue would give the accurate places of a sufficient number of stars from which pairs could be selected to observe for latitude, arrangements were made, before leaving Washington, with Prof. T. H. Saffoid, of Williams College, to make selections for our use from the large number collected by him during many long years of labor, together with the latest publications available, and to furnish us with the mean declinations for 1892 of stars properly located for observation along the boundary. By means of these lists of stars it was possible to observe as many pairs as were convenient on any one night, and to observe as many nights as were necessary to obtain a satisfactory result. Usually about 100 results for latitude were obtained, the number of pairs used varying from 20 to 60, with a resulting probable error of from ±0.03" to ±0.05". The apparent places were computed for the actual dates of observation, and the final result for latitude of the station was obtained within three or four days from the time of the last observation. AZIMUTH. The observations for azimuth were made with theodolite No. 725, 10-inch Fauth. The method used was that described in Bulletin No. 21, United States Coast and Geodetic Survey, 1890, entitled " Determination of an azimuth from micrometric observations of a close circumpolar star near elongation, by means of a meridian or transit and equal altitude instrument, or by means of a theodolite with eyepiece micrometer.'' This method is capable of great accuracy of result, but demands that an elongation mark be set up in the direction of a vertical plane passing through a close circumpolar star when near elongation, and that an instrument with an eyepiece micrometer be available to measure micrometrically the angle between the vertical planes passing through the mark and star. By. this method a satisfactory result for azimuth for a night could be obtained in from thirty to fifty minutes; one set or result taking about ten minutes. The instrument was too small and light to obtain the best results, but three sets per night and three nights gave an azimuth with a probable error of result of less than ±0.3"; the probable error of a .single result was aboirt ±0.5". More than four sets on the same night were found to add nothing to the accuracy of the mean for that night, but several nights' observations were needed as the mean results of different nights differed frequently by a second or more. Mean range for 15 stations =^1.2". As the observations were made very near elongation — within half an hour — and on both sides of that epoch, but a portion of one turn of the micrometer was used, and any error in the assumed values of the micrometer or of the chronometer correction was nearly eliminated from the mean result of the night. 36 UNITED STATES AND MEXICAN BOUNDARY. The atmospheric conditions were very favorable for both latitude and azimuth observations, the stars showing as bright points and very steady. The temperature of the observing tent rarely differed more than a degree froiA that of the outside atmosphere. All the observations for latitude, time, and azimuth were made by Assistant Astronomer John F. Hayford, and for a detailed description of the instruments used, method of observation and reduction, and for the results, see report of assistant astronomer hereto appended. Mr. James Page served as computer during the whole time devoted to astronomical observa- tions, and made all the astronomical computations, which were afterwards revised by Messrs. Hayford and Finley. Mr. H. B. Finley served as recorder for the astronomical party, recording all the astronomical observations, and in addition assisted in the measurement of horizontal angles for the triangulation. On the completion of the astronomical and triangulation observations at Yuma, Mr. John F. Hayford, assistant astronomer, and Mr. James Page, computer, were transferred to the party running the line between the Colorado River and monument 127, and Mr. H. B. Finley, recorder, to the party running the California line between the Colorado Biver and the Pacific. These gentlemen performed all their duties while with the astronomical party, often exposed to great hardship and discomfort, with zeal, energy, and intelligence. At several stations observations were continued throughout the entire night between sunset and sunrise, and during the days they were kei)t busy at the observation of time and magnetic declination, and in computing. Owing to lack of laborers, they worked also with pick and shovel to set the wooden piers and erect the astronomical tent to be ready for observations the night following the moving of observatory and camp from one station to another. The catalogue of stars furnished by Professor Safiford is herewith given in tabular form. In this catalogue the declinations are given to hundredths of a second, and have been revised by Professor Safiford since the latitude observations were made. The original declinations were given to tenths of a second only and used in computing the resulting latitudes. The column headed JS in the catalogue gives the correction to be applied to the catalogue declination to obtain the value used in comijuting the latitudes along the boundiiry. INTRODUCTION TO THE CATALOGUE. [By T. H. Sartbrcl.l This introduction is briefer than it would have been if I had not been taken suddenly and seriously ill when just completing the preparation for press. 1. Selection of stars. — The pairs were selected for the stations with especial reference to avoid- ing doubtful positions. The proper motions are the doubtful element owing to deficiency of old authorities. The best pairs then are those contained in Auwers' Bradley, and also observed very lately. The rejected stars were those which when data were collected, were found not to have been lately observed; when no good early authority was at hand. 2. General basis. — The system of the Berlin Jahrbuch (Auwei's') was adopted. This is quite generally employed as a standard by many of the best modern observers. It is fortunately very near that of the American Ephemeris (Boss's), but is rather farther north on the average, a few hundredths of a second only for 1802. The Jahrbuch system agrees still more closely with the Pulkova Catalogue for 1885, which has reached me since the computations were closed. This catalogue is based on an entirely independent investigation, with newly graduated circle and new ' constants of refraction. 3. Precession. — Struve's were used, as in the princii^al ephemerides. The terms depending on the cube of the time were taken into account where necessary. 4. Data employed in compilation. — All respectable catalogues of 1855 or since, with partial omission of the Eadcliff for 1860. In doubtful cases, the single years of the Radcliflf 1862-1875 and of the Washington observations were consulted; and in all, the latest Greenwich volumes available and the Karlsruhe observations. Special search was made for prime vertical declinations at Pulkova, Kasan, Gotha, and Washington; and in the other short but very accurate catalogue lately published in the Astrono- mische Nachrichten. 5. Proper motions. — Stars contained in Auwers' Bradley w( re examined if less than three observations in declination are there given. If indications were found that Bradley's observa- UNITED STATES AND MEXICAN BOUNDARY. 37 tions were inaccurate, they were investigated from all available authorities old aud uew; but if Auwers' proper motion seemed to be correct, it was employed, as also iji case of three or more observations. Stars not in Bradley were also completely investigated; in this case Piazzi or Groombridge was most commonly the best old authority. The method of least squares was employed in nearly all cases, the few exceptions being those where there were but two groups of nearly contempo- raneous good observations. The system on which the proper motions were calculated was inter- mediate between Auwers and Boss, to agree with those of the Jahrbuch stars which are not in Bradley. The weights were usually assigned on the system employed by Auwers in publications 14 and 17 of the Astronomische Gesellschaft; giving, however, one observation half weight, and unity 2-4. These values were also diminished for the less reliable series. Bradley's own data were taken with weight two-tenths for a single observation, three-tenths for two ; for more, as beforesaid, Auwers' proper motions were used without least squares reduction. The tiual i>robable errors were estimated on an average scale, where weight = 1 receives probable error ± 0.5". This is too large for the best modern observations. Piazzi and Groombridge were allowed weights = J, no matter how many observations are given in their catalogues. On the whole I think the final probable errors assigned are not too small, perhaps rather too large. 6. Final declinations. — The final declinations are brought up by the help of the assigned proper motions and reduced to the Jahrbuch's system by Auwers' systematic corrections or others derived from Boss or other sources and reduced to Auwers'. The Jahrbuch stars were most com- monly reduced with the proper motions there given; but more recent observations were added to the material tliere employed. They were found in the Ten Year Catalogue and in the Pulkova Catalogue of Romberg, besides frequently in others, in addition to the original njaterial. INTRODUCTION TO THE REVISION. The systematic corrections on the Jahrbuch system by Professor Auwers within a short time were applied on the original calculation sheets, for the stars marked A and C in the revision sheets. Stars marked C will require an additional correction of -f 0.1" to the declinations on the average owing to the different system by which the proper motions were calculated. Stars marked B have been investigated anew by least squares from all available material using the new system- atic corrections throughout. New catalogues luive been added in all these cases where such were published after the computations for the main catalogue; especially valuable were Greenwich 1800, year results, the new Glasgow Catalogue (1890), the prime vertical observations at Kasan, and the Cincinnati results reduced to 1900 for the proper motion stars. The following catalogues of fundamental stars received after the revision was nearly completed were not included: The Pulkova system of 1885 and the Madison of 1890. Both these agree closely in general with^he Jahrbuch system, aud the stars are so abundantly observed in detail elsewhere that the increase in accuracy would not be very considerable. Of course, if the latitudes on the boundary were to be redetermined the case would be difterent. According to my calculation (not duplicated for want of time) the sum of the corrections J 6 to the catalogue positions is +3.54"; if we add to this 0.1" for each of the 68 stars C, where proper motions have not been recomputed, we shall have +10.is4" or +0.016" for the average of the 624 stars. This is the mean reduction of the latitudes to the system of the Astronomische Gesellschaft, which, on the other hand, is now a few hundredths of a second north of the American Ephemeris system (Boss). The separate values z? S for stars of Classes A and C are of no special importance except in the few cases where they are more than 0.1", owing usually to new material; but those for Class B, being derived from a complete new solution by least squares of equations derived from all available material, should be employed in any further use of this catalogue. The chief cause of variation is the change in the systematic corrections for older observations, especially Piazzi's; some rather doubtful cases have had uew material. The Jahrbuch star 33 Bootis was i-ecognized as discrepant by Mr. Porro, of Turin, in the Astronomische Nachrichten, too late for any change, even in the revision. But I looked over the material collected by Argelander, and on the basis of this Mr. Porro prepared a later article in which he adopted my liyi)othesis that the discrepancy was due to proper motion, as in almost all similar cases. This again was put as doubtful by Argelander himself. Bradley has only two observations, one of which was made below pole, at a very low altitude, and hence can not be used as confirmation of the other, which is perhaps 3" wrong. 38 UNITED STATES AND MEXICAN BOUNDARY. Mean declinations of latitude stars. Class. Ko. B. A. C. Mag. AR. 1892. Anoual Tariation. DecHnatior, 1892. Probable error, 1892. Pr< mo per Annual preces- Sec var. AS h. m. «. ». . ' c 1 6.1 3 18 + 3.08 24 51 35. 26 *0.49 0. 000 +20. 051 — 015 +0.14 A 2 16 5.2 4 42 3 10 45 28 15. 75 .16 _. 0.6 20.049 018 A 3 32 5.0 9 1 3 10 19 36 21. 60 .18 + • 007 20. 037 026 + .10 C A 5 6.1 4.7 9 34 11 27 3 3 10 11 26 41 0. 03 38 4 55. 38 .28 .18 -• 030 007 20. 035 20.028 027 031 ^Z 52" C 6 57 6.8 12' 15 3 08 1 5 17.67 .16 + 015 20.024 033 — .07 A 7 58 4.5 12 41 12 36 11 11.01 .21 — . 047 20. 022 034 — .01 A 8 60 6.1 13 14 43 1129.25 .23 + 016 20.020 035 + .05 C 9 68 6.5 15 42 29 67 13 24. 32 .26 — 055 20.006 041 - .02 A 10 80 5.9 18 50 27 6113 57.04 .17 — 006 19.985 048 + .06 A 11 87 6.0 19 ,52 07 1 20 29.62 .16 _ Oil 19. 977 047 — .02 C 12 92 6.5 20 45 25 56 2 35.30 .38 + • 010 19. 971 051 A 13 109 5.6 24 25 15 29 9 21.93 .20 _ 057 19, 939 058 — .03 A 14 112 6.1 24 32 06 —4 33 15. 16 .13 _ 009 19.938 056 + .06 A IS prll6 7.0 25 10 08 15 26 27. 46 .24 + 022 19.932 058 + .u A 16 129 5.8 26 49 09 6 2132.29 .21 + 022 19, 916 061 + .01 C 17 142 6.2 29 19 08 12 46 37.94 .28 _ 054 19. 889 066 + ,06 C 18 152 5.6 30 54 24 43 53 33.61 .30 + 020 19.871 072 — .01 A 19 155 4.2 31 7 19 33 7 28. 98 .16 000 19. 868 072 + .02 A 20 163 6.8 32 33 06 -1 5 51.44 .14 _ 025 19.851 072 + .04 A 21 169 Var. 34 23 36 55 56 41. 65 .16 _ 038 19.828 082 + .05 A 22 173 5.3 35 16 24 38 51 57.29 .24 + Oil 19.816 081 — .19 A 23 180 5.1 36 2 32 49 55 12. 56 .18 — 003 19.805 084 + .04 C 24 182 6.4 36 18 41 58 9 40.39 .24 _ 007 19.8f.2 0S7 — .02 A 25 189 5.0 37 30 30 46 26 1.33 .20 _ 024 19.765 087 — .03 C 26 197 5.7 38 26 31 47 16 20. 30 .50 -). 033 19.771 089 A 27 198 4.8 38 42 32 47 41 35. 26 .16 — 016 19.767 090 + .04 A 28 211 5.5 40 54 17 14 53 10.23 .29 _ 050 19.734 090 + .07 A 29 214 6.0 41 31 16 18 59 17. 88 .23 + 010 19.726 091 + .02 A 30 215 4.2 41 37 16 23 40 46.57 .16 _ 072 19.723 092 + .03 A 31 219 5.0 42 43 37 50 22 44. 63 .19 — 015 19.714 lUO — .02 C 32 221 5.9 42 43 09 4 43 30.39 .18 — .15 19.705 092 + .01 A 33 222 4.6 43 5 11 6 59 49. 72 .14 — 037 19,700 093 + .08 A 34 223 5.5 43 18 17 16 21 26.68 .23 _ 197 19.696 095 + .02 A 35 228 5.7 44 10 58 63 39 33. 78 .17 — 018 19. 681 109 -1- .02 C 36 237 6.4 45 45 08 2 47 56.26 .21 _ 070 19.665 098 + .04 A 37 SU 5.3 48 35 53 58 23 15. 79 .23 — 080 19. 604 117 + .01 A 38 247 5.9 48 52 16 18 36 9.33 .19 _ 070 19.599 106 + .07 U 39 253 2.1 .W 11 57 60 7 .54. 18 .14 _ 015 19.574 122 + .02 A 40 254 6.2 50 14 55 58 35 50. 14 .22 _ 070 19. 573 121 + .06 C 41 fr 11 5.9 53 57 37 44 7 52.68 .32 _ 025 19.500 123 + .02 A 42 285 5.3 56 54 27 31 13 27. 30 .17 — 020 19.438 126 A 43 288 4.2 57 23 11 7 18 50. 43 .17 039 19.427 121 - .03 A 44 ec5.3 50 53 30 20 53 40. 98 .22 015 19.372 ! 129 + • 12 A 45 311 6.4 1 14 10 4 19 58. 96 .19 - 119 19.368 : 126 + .04 A 46 3 1 6.3 2 3 30 31 26 8. 38 .23 _ 033 10.322 137 + .02 A 47 327 5.7 3 25 98 68 12 13.15 .20 — 023 19.292 ! 167 - .02 C C 48 49 6.8 5.9 3 38 4 11 94 40 67 12 13. 57 41 30 25.47 .30 .21 I 030 040 19.287 , 19.272 166 145 + :o3 337 A 50 338 5.7 4 39 84 64 26 39. 34 .18 _ 019 19.260 165 + .06 C 51 345 5.2 1 5 9 29 30 51 0. 70 .37 000 19.248 143 A 52 374 5.9 18 06 —1 33 0. 47 .18 l. 220 19. 143 141 1 .32* A 62' 384 5.8 11 7 05 - 3 4 8 44 .18 _ 060 19. 095 144 + .01 A 53 388 5.2 12 14 09 3 2 43. 98 .18 _ 019 19.065 148 .,, A 54 394 6.4 13 53 94 64 5 29. 10 .33 _ 045 19.029 190 A 55 401 5.2 15 9 30 28 10 24. 53 .25 _ 088 18.984 163 — .03 A 66 404 5.0 15 59 50 44 57 45.37 .20 _ 005 18.961 175 -i- .03 A 57 406 6.9 17 3 06 -1 52. 62 .20 + 002 18.930 150 1- .02 A 58 409 5.8 17 30 41 37 9 3.91 .27 + 001 18.917 170 — 03 m 6,1 3.0 17 35 18 45 23 87 19 54 16. 40 59 40 25.94 - 004 036 18.915 18.880 165 197 416 C 61 425 6.0 1 19 58 49 42 53 49, 84 .31 - 070 18.845 182 + .06 * Glasgow position erroneous and now corrected. UNITED STATES AND MEXICAN BOUNDARY. Mean dedinalions of latitude stars — Contiuued, 39 cues. So. B.A.C. «,. AE. 1892. Annnal variation. Declination, P^^/jW' 1892. 0^«l' =K. Annual pre«8. Sec __!' i h.m.s. ». , „ , A 62 427 5.1 20 26 +3.22 18 36 36.48 ±0 21 +O.029 H-18.830 — 170 +0 12 A 63 431 5.8 20 52 3.23 18 40 50.88 23 _ 038 18.818 171 _l_ 02 A 64 432 5.0 21 12 3.66 44 60 55. 86 17 _ 104 18.808 187 _ 26 A 65 442 6.6 23 25 3.63 6 44 10. 64 26 — 057 18.739 170 + 18 A 66 441 5.7 23 37 3.57 46 26 59.78 25 _ 042 18. 733 194 ^ 02 C 6- 446 6.0 24 3 3.23 17 47 49.93 37 — 000 18.719 177 _ 03 A 68 448 5.0 24 32 3.13 5 35 13.22 18 _ 031 18.704 172 _ 02 A 69 453 3.8 25 42 3.20 14 47 19. 83 16 — 003 18.667 179 + 07 C 70 455 7.0 26 14 3.22 16 23 47. 55 30 _ 210 18.650 180 + 05 A 71 456 5.4 1 26 52 3.88 58 40 39. 21 13 _ 025 18.629 218 + 09 C 72 464 6.6 27 38 3.14 7 39 16. 52 22 — 030 18.604 179 + 01 C c 73 74 5.9 5.9 28 17 31 4 3.02 7 34 39. 13 57 26 37.45 26 34 I 075 005 18. 583 18. 490 173 227 - 07 05 482 A 75 487 3.7 31 22 3.65 48 4 51.09 14 — 111 18.480 215 + 01 A 76 492 5.2 32 52 3.58 43 50 11. 22 26 — 003 18.429 214 _ 02 C 77 501 5.8 34 11 3.56 42 45 2.70 32 _ 060 18. 383 216 00 A 78 499 5.5 34 33 4.55 70 4 36. 34 20 + 004 18.370 274 — 04 C A 79 80 6.1 4.7 35 17 35 49 3.32 3.12 25 11 59.94 ' 4 56 27. 26 23 + 040 005 18. 345 18.326 204 193 - 04 05 518 A 81 623 5.4 36 38 3.25 19 44 35.88 20 _ 668 18. 297 203 -1- 02 C 82 525 6.4 1 37 10 3.74 56 69 35.20 26 — 050 18.277 243 — 03 A 83 537 4.4 1 39 41 3.16 8 36 50.29 14 — 068 18.185 202 _ 03 C 84 544 6.1 42 16 3.51 37 24 53. 67 19 — 026 18.089 229 + 03 C '85 562 6.4 45 56 3.81 60 56 27.46 40 _ 000 17. 948 256 + 04 A 86 564 3.4 46 38 4.26 63 8 16. 52 14 — 022 17.921 286 — 02 A 87 569 3.7 46 55 3.41 29 3 8.89 17 _ 231 17.910 231 _ 07 A 88 574 4.4 47 58 3.10 2 39 14. 88 15 + 020 17.869 213 + 03 C 89 579 5.8 49 31 3.63 36 44 62. 58 20 + 006 17. 807 244 + 01 A 90 580 5.8 49 44 3.53 36 43 18. 22 22 + 019 17.798 245 _ 04 C 91 609 6.0 1 53 39 3.20 11 46 14. 23 22 — 040 17. 637 230 — 03 A 92 611 5.9 65 1 4.37 63 62 5. 18 17 + 006 17.580 315 + 02 A 93 614 5.1 55 7 3.96 63 57 54. 46 j 19 + 008 17.576 285 + 07 C 94 624 5.5 56 39 3.49 32 45 47.95 18 _ 010 17.511 256 _ 05 A 95 630 5.9 67 32 3.38 25 24 63. 34 24 + 013 17.473 250 + 06 A 96 633 .•i.8 -u 39 3.07 —0 23 32. 56 26 + 032 17. 468 227 + 15 A 97 639 6.4 58 16 3.06 —0 51 30. 62 16 _ 058 17.441 228 4. 02 A 98 619 5.0 2 1 68 3.59 37 20 47. 48 26 — 037 17.279 273 + 02 A 99 656 :i.l 3 7 3.55 34 28 34.36 15 _ 033 17.228 272 _ 06 A 100 661 5.8 4 20 3.62 38 3146.26 23 _ 004 17. 174 280 — 06 A 101 665 5.8 2 4 38 3.30 18 59 26. 08 19 _ 031 17. 160 267 -1- 02 A 102 666 6.8 5 3 3.40 25 25 38. 34 26 + 001 17. 141 265 + 16 A 103 66- 6.4 5 6 3.49 31 1 1.17 29 _ 020 17. 139 272 + 01 A 104 668 6.1 6 1 4.61 66 1 4.03 15 _ 004 17. 097 353 _ 02 A 105 675 5.3 6 6 3.46 29 47 47.92 18 _ 055 17.093 272 _ 02 A 106 676 5.2 6 27 3.74 43 43 28.03 26 _ 019 17.077 293 + 07 A 107 684 4.5 7 17 3.18 8 20 23.61 16 _ 001 17.039 252 + 05 A 108 691 5.3 9 33 3.53 32 51 24. 10 20 _ 021 16.933 283 00 A 109 693 5.8 9 35 3.40 24 32 31.67 35 _ 085 16. 932 273 + 03 C 110 6.6 10 28 4.54 63 55 26. 23 28 — 040 16. 891 365 — 03 A 111 696 6.5 2 10 29 4.18 57 54.32 29 _ 010 16. 890 336 00 A 112 698 4.3 10 54 3.55 33 20 60.74 17 _ 034 16. 870 287 _ 04 c 113 702 7.0 11 55 4.66 63 50 17. 65 36 000 16.822 1 369 + 05 A 114 707 5.6 12 7 3.32 19 24 4.58 16 + 010 16. 812 272 + 02 A 115 710 S.5 12 41 3.46 28 8 38. 02 23 + 014 16. 785 284 — 02 A 116 721 5.4 14 60 4.14 55 21 3.50 20 _ on 16.682 343 _ 09 A 117 732 5.8 16 42 3.07 —1 22 37. 43 21 — 052 16. 590 256 + 03 A 118 745 5.5 19 2 3.21 10 7 16. 37 17 _ 013 16.475 274 — 03 A 119 744 4.3 20 10 4.85 66 54 59. 05 15 + 003 16.418 415 _ 05 A 120 757 5.4 21 50 3.50 29 11 12. 85 18 _ 085 16. 334 304 _ 05 A 121 759 6.5 2 22 28 3.51 29 26 44.01 27 + 066 16. 301 305 + 02 A 122 760 4.3 22 25 3.18 7 58 32.51 13 _ 001 16.304 277 — 01 A 123 772 5.6 25 31 3.64 35 40 4. 20 22 + 014 16. 145 322 00 40 UNITED STATES AND MEXICAN BOUNDABY. Mean dccUiiallons of latitude Ktars— Continued. Class No. B. A. C. Mag. AR. 1892. Annual variation 1 Declination, 1892. Probable error, 1892. Proper motion. preces sion. see. var. A5 Ii.m.s. I ... , „ „ „ „ „ A 124 786 5.6 29 13 +3.62 34 12 57. 88 ±0.20 —0.036 +15.950 -0 327 —0 08 A 125 791 5.8 29 23 3.95 — 8 19 53.95 .28 — .071 15.942 .268 _ 16 A 126 792 6.7 29 55 3,01 — 4 1 13.55 .23 — .427 15.913 .274 _ 16 C 127 795 7.0 31 54 5.46 71 9 38. 69 .21 .000 15. 808 .499 + 01 A 128 808 5.6 32 41 3.39 21 29 38. 86 .16 — .011 15.765 .313 01 A 129 816 5.9 35 19 4.25 64 38 40.68 .27 — .025 15. 621 .395 + 22 130 819 6.1 35 23 4.19 53 3 64. 50 .35 — .015 16.618 .390 00 A 131 830 6.3 2 36 40 3.22 10 16 61. 05 .24 — .028 15.647 .304 + 05 A 132 829 5.7 37 3 3.89 43 60 14. 63 .24 — .034 16. 526 .365 03 A 133 831 4.9 37 7 3.60 27 14 50. 03 .17 — .009 16.622 .331 _ 02 A 134 844 5.1 39 4 3.26 11 69 27.51 .20 — .069 15.413 .310 _ 01 A 135 845 4.2 39 6 3.23 9 39 28. 32 .15 -.020 16.412 .307 _ 02 A 130 861 4.9 41 29 3.56 28 47 63.48 .23 — .110 16, 278 .342 , . 02 A 137 866 5.8 42 29 3.47 24 44 13.58 .28 + .002 15.221 .336 + 02 A 138 863 3.8 42 49 4.67 55 26 48. 08 .19 — .034 15. 201 .419 05 A 139 871 4.6 43 46 3.75 37 52 25. 40 .21 — .087 16. 147 .366 _ 10 A 140 885 4.1 46 36 4.21 52 19 11. 96 .13 — .009 14.984 .416 + 06 A 141 7.0 2 40 51 4.10 50 43 30. 36 .37 — .030 14.969 .410 + 04 05 A 142 888 5.8 46 54 3.77 37 53 49.75 .30 — .063 14. 967 .372 C 143 893 6.5 47 11 3.33 16 2 31.66 .34 — .075 14. 950 .330 _ 06 C 144 6.3 49 16 3.94 50 49 27. 10 .32 — .030 14. 827 .416 + + C 145 914 5.7 62 30 4.05 46 47 15 68 .29 + .020 14. 636 .410 02 C 146 943 5.0 57 26 4.46 56 16 51.85 .26 + .065 14.338 .442 06 A '147 '957 5.7 59 6 3.51 24 50 4. 10 .23 — .013 14.235 .366 00 A 148 963 var. 3 1 8 3.88 40 32 20.99 .16 + .010 14.109 .409 01 A 149 967 4.3 2 13 4.02 44 26 51. 60 .21 — .160 14.042 .423 + A 150 974 5.8 3 7 3.59 28 39 60.46 .21 -.026 13.986 .382 06 A 151 981 5.0 3 4 19 3.85 39 12 3.34 .21 + .020 13.910 .411 07 C 162 987 6.3 5 26 .3.29 12 38 16. 49 .24 + .010 13.840 .363 01 A 153 986 4.3 5 27 3.42 19 19 4. 27 .13 + .DOS 13.838 .366 03 C 154 991 6.0 6 42 3.18 6 16 13. 29 .36 - .010 13.759 .343 01 A 155 999 4.8 8 42 3.44 20 38 37. 94 .18 — .070 13. 632 .374 10 A 156 1,006 6.6 10 31 4.01 43 37 39. 13 .23 -.044 13.514 .438 03 A 157 1.007 5.4 10 56 4.24 49 49 33. 61 .17 — .027 13.487 .464 01 li 158 1,017 5.0 11 58 3.74 33 49 37. 98 .21 -.002 13.420 .411 _ 38 A 159 1, 023 5.9 13 29 3.67 26 40 48.27 .27 — .080 13.322 ..396 01 A 160 1, 028 5.0 13 42 3.12 2 58 25.50 .17 + .110 13.307 .347 00 A 161 1,041 6.0 3 15 28 3.13 3 17 10. 23 .23 — .037 13. 191 .350 _ 03 A 162 1.0.58 4.5 20 19 4.82 59 33 48.15 .14 1 .012 12.808 .544 — 05 A 163 I, 099 4.8 28 49 4.24 47 49 57.92 .20 - .038 12. 290 .494 + 08 C 164 1,105 6.6 30 42 4.04 42 13 35. 50 .30 — . 020 12. 159 .473 00 A 165 i,ir2 4.4 31 22 3.07 3 30. 23 .20 — .501 12. 113 . 362 + 07 C 166 1,114 6.5 31 44 3.37 15 4 31. 54 .32 - .010 12.087 .396 -1- 06 A 167 1,111 5.5 32 47 5.15 62 51 58. 20 .18 H .058 12.013 .608 00 C 168 1,123 5.S 34 6 3.90 37 13 51.21 .27 - .040 11.921 .461 — 01 A 169 1,128 5.9 34 14 3.12 2 43 19.01 .22 + .019 11.912 .372 — 04 A 170 1,132 5.0 35 32 3.86 33 37 5. 00 .26 -.003 11. 820 .452 — 01 A 171 1,135 5.5 3 36 5 3.45 19 21 14. 18 .18 — .007 11.781 .412 + 02 B 173 1,133 5.3 36 36 .5.19 63 11 80 .28 — .010 11.745 .620 + 40 A 173 1,138 4.0 37 33 3.75 31 66 44. 21 .22 - .010 11.677 .449 _ 07 A 174 1,139 4.0 37 51 4.05 42 14 12. 35 .17 -.012 11.666 .487 + 01 A 175 1,140 6.2 37 32 3.55 19 19 23. 48 .21 — .034 11.677 .414 -1- 02 C 176 1,143 6.9 38 11 3.48 20 35 13. 82 .27 .000 11.632 .419 _ 02 c 177 1,142 5.9 38 26 ■ 4.18 45 20 31. 70 .31 — .020 11.614 .501 + 10 A 178 1,137 4.5 38 58 6.22 70 69 54. 94 .20 -.051 11.576 .748 -(- 04 A 179 1, 1.58 6.0 39 25 3.06 — 38 12. 82 .2! ; .012 U. 643 .370 + 22 A 180 1,161 4.9 39 55 3.55 23 36 41.21 .20 — .042 11.604 .429 + 03 C 181 5.9 3 41 41 4.12 43 37 44.. 38 .40 + .010 11. 381 .500 ..|_ 02 c 182 1,192 5.8 43 49 3.59 25 15 10.72 .28 — .110 11. 226 .439 - 02 c 183 1,206 6.0 46 59 3.43 17 17.90 .19 — .036 10. 995 .421 00 A 184 1,212 5.6 47 22 2.96 -5 41 3.16 .18 — .007 10. 969 .366 - 10 ' apart: mean of the t UNITED STATES AND MEXICAN BOUNDARY Mean declinations of latitude stars — Continued. 41 - No. B.A.C. Mag. AR. 1892. h. m. .. Annual variation. Declination, ^'^ 1892. «7g ri»i Annual preeeu- Sec var. di ». , „ ! „ , A 185 1,214 4.5 48 35 +4.43 50 22 55.01 ±0 17 -0 125 +10. 879 — 547 + 0.09 A 186 1,219 3.3 50 36 4.01 39.41 50.20 15 1- 016 10. 730 499 — .10 A 187 1,228 4.1 51 .57 3.88 35 28 47. 69 16 ) — 013 10. 630 484 — .09 A 188p. 1, 238' 6.7 54 32 3.58 22 53 48.05 28 j- 016 10. 438 447 + .05 C 189 1,240 5.9 54 35 3.44 17 53 19. 52 31 ! - 047 10.434 433 .00 A ■190 1,241 {';^f} 54 42 3.32 12 11 4.89 14 1 — 009 10.426 418 ^■ .01 A 191 1,262 5.3 59 59 3.67 27 18 29.44 24 — 061 10.028 468 + .06 A 192 1,266 4.3 4 49 4.33 47 25 24. 72 14 — 9.964 553 + .08 A 193 1.268 6.3 1 7 3.65 37 26 37. 25 27 — 142 9.942 500 + .05 A 194 1,279 5.8 4 15 3.64 26 11 54.98 17 — 037 9.703 470 — .08 A 195 1,287 4.1 6 58 4.38 48 8 3.33 19 — 027 9.494 507 + .07 A 196 1,302 0.2 9 38 3.40 15 7 47. 90 20 — 010 9.287 442 — .10 C 197 1,301 4.9 10 7 4.48 50 1 45. 36 22 j - 050 9.250 685 + .04 A 198 1,322 5.4 13 24 3.89 34 18 19.31 20 + 001 8:995 511 .00 A 199 1,323 .^.0 13 44 4.32 46 14 24.47 22 - 040 8.968 567 + .03 A 200 1,328 4.0 13 39 3.41 15 21 58. 59 16 — 030 8.975 447 + .07 A 201 1,346 4.0 4 16 42 3.45 17 17 19.48 16 — 025 8.735 456 — .08 A 202 1,350 6.0 17 13 3.43 16 31 28.47 23 — 032 8.694 454 + .03 A 203 1,357 5.3 17 58 3.26 9 12 32.84 26 — 004 8.635 434 — .04 A 204 1,364 5.7 19 14 3.81 31 11 40. 55 30 - 116 8.536 506 + .03 A 205 1,371 5.9 20 50 3.58 22 45 8.50 20 — 003 8.409 478 .00 C 206 1,373 6.0 21 36 3.55 21 22 -42. 44 31 — 050 8.348 474 — .04 A 207 f 11 1,382 5.7 23 29 4.73 53 40 31.30 14 — 009 8.198 633 + .10 C 209' 11 1,398 5.8 25 49 4.21 42 49 57. 22 21 000 8.011 566 + .07 A 1,414 4.8 29 12 4.14 41 2 31. 84 23 — 024 7.738 561 — .04 A 209 1.421 4.6 29 43 3.21 9 56 18. 84 25 — 054 7.696 446 + .06 A 210 1,424 5.7 3125 4.73 53 15 34.46 17 — 091 7.560 627 — . 03 A 211 1,425 5.7 4 31 24 4.71 52 61 48. 74 20 - 019 7.560 639 — .04 A 212 1,442 5.6 34 3 3.33 11 59 5. 27 25 - 022 7.346 455 + .11 B 213 1,460 5.7 38 27 3.31 10 56 40. 37 32 + 007 6.986 456 + .13 A 214 1,456 5.6 39 4.58 56 33 52. 25 14 j- 156 6.940 683 + .07 A 215 1,469 3.9 40 6 3.00 - 3 27 11. 14 14 : — 002 6.850 413 — .06 A 216 1,474 4,5 43 19 5.92 66 9 30. 08 12 — 001 6.585 820 + .02 A 217 1,491 44 43 3.26 8 42 51.51 21 — 031 6.468 463 - .01 A 218 1,495 4.1 45 27 3.19 5 25 11.73 16 - 002 6.408 444 — .03 A 219 1,494 5.8 46 13 4.89 55 4 48.40 22 — 0U9 6.345 679 + .10 A 220 1,514 3.8 48 38 3.12 2 15 48. 09 13 - 007 6.145 436 + .01 A 221 1,528 5.8 4 5133 3.67 24 52 58.87 20 — 019 5.901 513 -.02 A 222 1,535 6.4 52 57 4.12 39 29 26.13 27 — 006 5.784 579 . - .13 A 223 1,536 4.3 53 49 5.31 60 17 0.80 14 — 014 5.711 746 — .10 A 224 1,540 var. 54 13 4.30 43 39 46. 21 15 — 014 5.677 603 + .03 A 225 1,541 3.9 54 56 4.18 40 55 3. 36 15 — 008 .5. 617 588 — .07 A 226 1.551 4.8 56 38 3.58 21 26 6. 42 16 - 040 5.473 504 -.02 A 227 1,558 3.5 58 56 4,20 41 5 16. 16 14 — 061 5.279 593 -.06 A 228 1,568 5.2 5 14 3.54 18 29 58.20 19 + 022 5.100 497 + .08 B 229 1,572 5.8 1 32 3.65 24 7 18. 68 30 000 5.061 517 + .22 C 230 1,582 6.0 2 40 4.45 46 49 40.17 26 - 160 4.964 631 + .03 C 231 1,601 5.7 5 5 29 3.44 15 54 41. 96 27 + 010 4.725 490 + .04 A 232 1,614 5.3 8 22 3.90 32 33 43.41 22 + 013 4.479 555 + .00 A 233 1,027 5.0 11 5 3.92 33 15 29.46 22 - 154 4.247 662 + .05 A 234 1,642 5.4 14 13 5.12 57 26 18.78 20 — 058 3.979 734 + .02 A 235 1,663 5.7 17 19 4.07 37 17 2. 05 21 + 001 3.713 585 + .04 A 236 1,687 1.9 19 21) 3.22 6 15 4.52 16 — 015 3. 539 463 + .08 A 237 1.681 2.0 19 28 3.79 28 30 56. 24 14 - 180 3.528 545 + .01 A 238 1.676 5.9 19 68 5.65 62 58 33. 81 14 — 008 3.485 816 - .01 A 239 1.730 2.2 26 29 3.06 — 22 46.83 16 - 005 2.922 443 + .03 A 240 1.748 4.9 5 28 53 3.29 9 24 57. 10 20 — 002 2.714 477 + .09 A 241 1,766 4.6 5 30 58 3.29 9 13 53.20 23 - 305 2.533 477 + .07 B 242 1,751 5.9 31 37 0.00 65 38 10.87 31 — 036 2.477 870 + .03 A 243 1.794 1.9 35 19 3.02 — 2 0.50 16 + 010 2.156 440 + .16 A 244 1,797 6.2 37 24 5.05 56 4 12. 08 20 — 051 1.974 734 .00 A 245 1,837 5.2 42 23 3.68 24 31 50. 69 20 - 010 1.539 536 + .01 S. Doc. 247- UNITED STATES AND MEXICAN BOUNDARY. Mean declinations of latihide stars — Continued. Class. No. B.A.C. Mag. AR. 1892. variation. Declination, ^^^ 1892. YJ able 2.' Proper Aunnal Preces- Sec. var. AS 240 1,845 4.1 h.m.e. 44 +4.15 39 58.32 ±0 16 +0.032 + 1.398 -0. 605 -0 02 C 247 1,870 4.8 47 59 3.55 20 15 19. 66 17 — .096 1.051 .520 00 248 1,885 4.0 50 38 4.94 64 16 32.23 14 - .117 .819 .719 — 03 C 249 1,896 6.3 61 18 3.72 25 56 23. 31 21 — .005 .762 .543 + 04 A 250 1,895 2.0 51 36 4.40 44 56 8. 65 16 - .011 .734 .042 + 03 ,. 251 1,928 4.7 50 26 3.30 9 38 48. 56 31 + .020 .311 .481 — 00 A 252 1,945 6.9 .19 10 3.17 4 9 51.03 16 - .013 ,064 .462 — 03 A 253 1,958 4.6 1 24 3.42 14 46 50.97 14 — .013 - .123 .499 + 03 A 254 1,963 6.8 3 20 4.00 48 43 55. 44 24 — .063 .292 .670 H 06 A 255 1,992 5.7 7 67 5.54 61 32 57. 46 21 — .005 ,096 .807 — 06 A 256 2,009 5.0 9 11 3.46 16 10 32.72 18 + .005 ,804 .504 + 08 A 257 2.017 5.5 10 23 3.37 12 18 6.24 18 + .199 .908 .490 _ 03 A 258 2,022 5.7 11 9 3.31 9 58 52. 01 23 -.059 .976 .481 — 01 A 259 2,024 r,.7 12 59 4.87 63 30 1.93 23 — .090 1.136 .709 + 17 A 260 2,044 5.4 16 36 4.63 49 20 32. 30 16 — .012 1.450 .072 00 C 261 2,040 5.7 6 17 19 5.07 56 20 29. 22 50 .000 1.513 .737 + 18 A 262 2, 074 6.2 21 24 5.22 58 14 28. 30 17 -.334 1.870 .757 + 01 A 263 2, 120 4.8 27 4 3.25 7 24 41.48 21 -r .004 2.363 .409 + 12 A 264 2,156 5.7 31 18 4.18 39 59 39.85 22 — .011 2.730 .603 + 09 A 2641 *2, 163 2.2 31 28 3.47 16 29 27. 34 13 — .036 2.745 .499 + 04 A 265 266 6.1 3.3 31 X- 37 17 3.22 3.69 6 13 32. 69 25 14 15. 09 60 14 + .037 — .005 2.757 3.248 .464 .530 - 09 2,194 A 267 2, 192 5.8 37 37 5.13 67 16 49.63 22 — .037 3.277 .736 + 07 A 268 2,200 5.6 38 57 4.33 43 41 3. 06 18 + .147 3.392 .641 00 A 269 2,201 5.7 39 26 4.68 48 54 10.21 23 -.004 3.433 .677 + 03 A 270 2,223 5.1 43 8 4.25 41 54 27. 52 27 — .130 3.751 .607 + 08 A 271 2,233 5.6 6 45 5 3.00 2163 16.70 26 — .038 3.919 .513 00 A 272 2,235 6.4 45 36 4.13 38 59 49. 99 22 + .002 3.963 .589 — 03 A 273 p 2,275 6.8 62 8 3.70 26 13 20.21 21 + .083 4,522 .526 + 03 A 274 2,330 5.7 7 2 10 3.44 16 6 9.30 19 — .104 5,374 .482 + 04 A 275 2,350 5.9 6 53 3.65 24 18 31.45 18 -.037 6.685 .608 _ 03 15 270 2,361 ;>.7 7 49 4.46 47 25 52. 26 37 — .162 6.847 .020 A 277 2, 381 5.8 10 32 4.19 41 4 28.16 18 + .023 6.074 ,579 ^ 15 A 278 2,410 3.5 13 40 3.69 22 10 50. 71 17 1- .003 6,336 .494 -1- 09 A 279 2,416 5.5 14 50 4.02 30 57 47. 30 16 — .009 6.431 .,553 „ 06 A 280 2,467 5.3 22 37 3.75 28 20 24, 44 22 — .053 7.073 .508 — 01 A 281 2,469 5.0 7 23 6 3.74 28 8 17.99 22 -.018 7.112 .507 + 01 A 282 2,480 5.6 20 30 3.12 2 8 35.22 27 + .023 7.390 .420 05 A 283 2,504 5.9 3! 27 3.94 35 17 23.28 24 + .024 7.791 .526 + 02 A 284 2,533 6.6 36 41 ,5.48 63 6 24. 38 19 — .066 8,210 .724 00 A 285 3,549 5.9 37 32 3.67 26 2 26.70 21 -.026 8.278 .483 ^ 10 li 286 5.7 39 27 4.02 37 46 42. 00 40 + .030 8.431 .527 + 10 A 237 2,606 6.2 46 38 4.38 47 39 53. 08 25 — .014 8,997 .567 + 02 A 288 2,639 6.1 60 52 3.41 16 4 41.97 21 — .026 9, 326 .436 + 03 ]i 289 6.0 55 31 3.18 5 10 35. 40 50 + .037 9. 685 .401 00 290 2,704 6.0 4.97 58 33 49. 70 33 — .075 10, 117 .620 B 6.1 18 10 3.85 35 21 36. 66 50 .000 11.370 .458 04 A 292 2,815 6.0 19 54 3.06 28 14 55. 57 20 — .117 11.494 .434? + A 293 2,842 6.4 24 56 i.d 65 30 45.76 17 -.063 11.8.52 .636 _ 06 C 294 6.1 28 34 3.04 — 1 47 1. 15 60 .000 12. 108 .348 + 35 A 2,892 6.0 31 17 4.47 53 5 22.49 25 -.031 12.296 ,511 09 A 296 2,958 5.8 38 53 3.26 10 28 21.27 31 + .007 12.815 .363 _ 07 A 297 2,076 6.4 41 47 3.06 - 1 30 6.00 26 + .017 13.008 .332 _ 34 A WT 3,003 5.8 47 22 5.22 65 59.26 17 — .090 13. 376 .560 + 14 A 298 f U 3,052 5.6 51 33 3.36 15 59 44. 59 22 + .030 13.647 .355 + 01 A 299 3,075 3.5 56 15 4.13 47 34 59.41 17 — .068 13. 946 .426 01 A 300 f 11 3,162 4.0 9 12 7 3.75 37 15 33. 50 17 — .114 14. 909 .359 00 A 301 3,204 4.6 18 22 3.51 26 38 49.13 19 -.036 16. 269 .326 _ 13 B 302 3,273 5.0 30 18 3.57 31 38 44. 45 36 - .012 15. 925 .311 _ 95 C A 6.1 35 12 44 46 3.66 4.13 3146 5.64 54 34 7. 42 50 18 .000 + .025 16. 182 16.661 .301 .327 04 02 304 3,358 4.7 - UNITED STATES AND MEXICAN BOUNDARY. Mean declinatioM of latitude stars — Contiuued. 43 Class. No. B.A.C. Mag. AE. 1892. Annual variation. Declination, P™^ 1892. 7/ able 2.' Proper motion. Annual [ preces- | Sec .a. A6 A 305 3,407 6.4 h.m.i. 52 24 +3.18 8 49 45.46 ±0 25 -0. 015 —17. 024 -0 238 +0.04 A 300 3,505 3.5 10 10 35 3.04 43 27 12. 02 15 _ 058 17. 811 218 02 A 307 3,522 5.7 13 51 3.27 20 1 7.70 20 _ 201 17.941) 207 _ 06 A 308 3,531 5.0 16 20 4.40 66 6 44. 40 16 _ 014 18.036 272 00 A 309 3,590 5.1 24 3.05 — 2 11 11.39 18 _ 018 18. 319 173 + 19 A 310 3,593 4.9 25 54 5.28 76 16 8 71 17 _ 005 18.386 298 01 B 311 3,637 var 10 32 13 2.96 -12 49 23.00 36 000 18.600 153 00 A 312 3,691 5.8 40 35 3.24 19 27 39. 02 21 _ 036 18. 861 152 + 08 A 313 3,729 4.9 47 46 3.47 43 45 53. 11 19 _ 027 19.065 148 _ 01 A 314 3,749 6.0 50 9 3.09 1 18 45. 42 20 + 008 19. 129 126 _ 12 A 315 3,777 2.0 57 4 3.76 62 20 2. 31 15 _ 071 19. 301 141 _ 01 A 316 3,784 5.8 58 31 3.35 38 49 22. 76 21 _ 013 19. 336 121 + 01 A 317 3,788 4.8 59 27 3.10 7 55 11.43 15 _ 022 19. 357 111 _i. 07 A 318 3,801 6.5 11 153 3.22 23 54 26.44 29 .). 016 19.411 111 + 06 B 319 3,825 6.7 6 27 3.52 55 28 52.15 50 _ 002 19. 508 111 05 A 320 3,842 5.0 9 28 3.20 23 41 2. 64 21 + 003 19.567 094 + 06 A 321 3,856 4.7 11 13 15 3.29 38 46 40.19 26 _ 068 19.637 089 + 01 A 322 3,862 4.2 15 34 3.10 6 37 16.10 14 000 19. 677 079 00 B 323 3,864 5.9 16 26 3.61 64 55 17. 35 17 + 040 19. 692 091 _ 05 B 324 6.0 23 41 3.41 57 20 1. 57 36 _ 012 19. 802 070 27 A 325 3,916 5.0 24 48 3.06 — 2 24 27. 53 13 ODD 19.817 060 + 13 A 326 3,933 5.5 29 43 3.58 69 55 25.59 17 _ 127 19.878 068 01 B 327 3,953 6.1 32 45 3.25 47 25 58. 37 32 _ 034 19.911 048 + 63 B 328 3,975 6.5 38 24 3.06 -6 4 35.56 27 _ 023 19.964 034 30 A 329 3, 981 4.0 40 21 3.19 48 22 41. 60 15 + 030 19. 979 032 00 A 330 3,995 2.1 43 33 3.00 15 10 32. 87 14 _ 098 20.001 024 j^ 03 A 331 4,017 2.4 11 48 9 3.18 54 17 42. 78 15 + 008 20.026 016 + 02 C 332 6.1 51 41 3.12 40 56 48.21 ] 34 _ 060 20.040 008 _ 11 A 333 4,066 5.9 58 45 3.08 22 3 38.21 1 22 + 004 20.053 + 00 1 _ 01 A 334 4,072 4.2 59 42 3.06 9 19 58. 17 14 + 049 20.053 008 _). 03 A 335 4,110 5.8 12 6 40 3.06 21 8 36.41 26 _ 018 20.044 020 _ 01 A 336 4,126 5.8 10 43 3.02 41 15 40.83 18 _ 031 20.031 029 _ 03 A 337 4,151 5.2 14 52 3.04 3 54 50. 55 . 19 _ 063 20. Oil 037 _). (15 A 338 4,195 4.6 21 33 3.00 28 52 7. 56 17 _ 086 19.964 050 _ 06 B 339 6.0 22 15 2.96 41 57 10.73 35 _ 012 19.958 050 03 A 340 4,212 5.8 24 18 3.01 21 29 39.39 20 _ 017 19.940 056 + 01 A 341 4,216 5.6 12 24 55 2.83 59 0.23 13 + 100 19. 934 053 _ 03 B 342 4,233 5.3 28 20 2.96 33 50 39.60 30 — 025 19.900 062 _ 50 A 343 4,246 5.2 2.57 70 37 1.38 23 _ 005 19.879 058 + 02 A 344 4,248 6.0 31 33 3.01 17 41 4.57 21 _ 022 19. 863 069 + 03 A 345 4,257 4.9 33 40 3.09 - 7 24 4.44 13 _ 021 19. 837 075 + 14 B 346 4,282 6.2 39 21 2.85 44 41 38. 17 36 000 19. 758 080 + 03 B 347 4,287 5.6 40 3 2.83 46 1 50.09 26 + 005 19. 747 080 ^ 21 A 348 4,315 5.0 46 26 2.93 28 7 42. 37 17 _ 018 19.643 094 _ 07 A 349 p ■ec4,318 6.3 46 50 2.98 17 39 41.57 31 000 19. 636 096 _ 07 C 350 6.2 49 4 2.88 34 7 10.23 45 + 015 19. 595 098 _ 03 A 351 4,347 '..1 12 51 11 66 1 27. 65 24 051 19. 555 087 - 05 A 352 4,351 5.1 53 35 2.97 17 69 30.43._ 23 + 052 19. .507 109 -1- 17 A 353 4,352 5.9 54 6 3.09 — 3 13 45. 43 "■ 17 + 010 19.497 114 — y A 354 4,365 5.7 55 50 2.31 67 10 47.82 18 _ 013 19.461 090 _ B 355 4,389 5.9 13 1 1 2.71 45 50 45. 87 32 + 025 19.346 113 + 13 A 356 4,388 6.0 1 7 2.95 23 11 44.76 26 _ 031 19.344 121 + 14 A 357 4,401 4.4 4 21 3.10 — 4 67 44. 57 14 - 037 19. 267 134 + 07 A 358 p ec 4, 408 6.3 4 44 2.77 39 6 33. 51 27 + 007 19. 258 122 — 01 B 359 4,423 6.0 7 10 2.99 12 7 50. 14 28 _ 024 19. 198 134 _ 14 B 360 6.6 9 47 2.09 67 51 36. 45 34 + 004 19. 131 099 _ 25 A 361 4,456 5.0 13 13 39 2,56 50 15 0,06 22 001 19. 026 127 _ 06 A 362 4,477 6.1 17 43 3.10 —4 21 33.45 24 — 010 18.911 159 + 45 B 363 4,497 6.6 22 18 2.06 63 48 56. 75 17 + 207 18. 773 117 — 36 A 364 4,506 5.9 23 23 1.52 72 57 8. 33 26 _ 023 18.740 088 + 07 C 365 4,502 6.5 23 42 3.08 -0 48 13. 28 32 — 060 18.730 167 — 02 A 366 4,521 5.4 27 17 3.15 -9 36 30. 37 22 - 023 18.616 179 + 17 44 UNITED STATES AND MEXICAN BOUNDARY. Mean declinations of latitude stars — Continued. Class. ~Ko. B. A. C. Mag. AK. 1892. Annual variation. Declination, '^^°^^ 1892. jg able 2'. Proppi- motion. Annual preces- sion. Sec.v.^r. A« h. m. s. s. , „ ,. B 367 4.526 1 6 27 41 -1-2.84 M 54 27.80 ±0 31 —0.200 —18. 603 +0. 163 -0.10 C :i68 4,536 1 5 29 58 2.68 37 44 8.58 17 -.015 18. 527 .1.58 + .02 A A 369 370 34 35 35 31 1.43 2.80 71 47 30.90 20 30 7.47 19 19 + .011 + .023 18. 369 18.336 .092 .177 .00 + .03 4.562 1 5 A 371 4,505 1 5 13 35 57 3.14 — 8 9 28.52 14 + .046 18.321 .195 + .02 J! 372 373 37 53 41 .38 2.57 2. 56 42 13 0.95 41 37 49. 18 27 34 H- .015 — .058 18. 252 18. 113 .163 .168 — .15 + .22 4,596 1 6 A 37i 4, 607 I 43 17 2.37 49 51 8.64 13 — .014 18.051 .160 + .06 A 375 4,618 ' 5 44 36 2.83 21 48 1.15 23 + .016 18.000 .190 + .05 li 376 47 1 2.94 12 41 .56. 58 41 - .020 17.906 .201 — .28 377 4,649 5 64 15 35. 20 22 -.017 17.792 .157 — .10 K 378 c 54 14 3. 10 — 3 1 24.71 30 — .068 17.613 .223 + . 11 379 55 29 1.67 65 25 6. 34 40 .000 17.560 .125 + .16 B 380 .56 2.90 9 25 3. 00 31 + .020 17.539 .217 — .10 C 381 14 5 26 1.87 59 50 57.60 26 - .049 17.124 .150 .00 B 382 4,713 4 6 48 2.71 2 55 4. 85 34 — .020 17. 061 .240 -.15 A 383 4,724 1 . 9 34 2.94 10 36 33. 89 25 -.15) 16. 933 .238 + .11 A 384 4,741 4 12 17 2.28 46 35 3.56 24 + . 151 16. 804 .191 + .04 A 385 4,742 1 4 12 20 2.13 51 51 55. 60 16 + .085 16.801 .178 + .10 A 386 4,753 . 14 39 2.84 16 48 6. 57 17 + .058 16. 691 .238 + .03 B 387 388 17 44 27 11 3.05 2.59 1 44 51. 76 30 50 44. 36 34 16 -.475 + .125 16. 539 16.058 .259 .234 — .26 + .04 4,808 S B B 390 28 47 29 36 1.62 2.54 60 42 5.76 33 29.79 20 26 + .010 15. 974 15. 931 .152 + .04 -f .21 4,820 '• e A 391 4,843 [ 5 14 34 49 2.23 44 52 14.25 21 -.049 15. 049 .211 + .05 B 393 ! 5 35 28 2.73 22 26 20. 13 34 + .080 15.614 .257 — .23 B 393 4.870 ' 5 39 33 2.33 40 54 58.60 36 + .020 15. 380 .225 — .10 A 394 4,873 j 4 40 12 2.80 17 25 18. 38 27 — .052 15. 350 .270 + .02 B 395 1 J 43 36 2.67 24 48 55.30 34 + .035 15.157 .262 .00 A 396 4.903 i 5 45 28 2.14 46 33 58.48 -!o98 15. 050 .212 + .02 B 397 4,906 1 5 46 14 2.37 37 42 55. 09 23 + .100 15. 005 .237 — .59 B 308 4,918 i 5 48 42 1.52 59 43 58. 80 19 + .140 14.861 .156 .00 B 399 4,933 1 5 52 10 2.80 16 49 23. 39 30 .000 14. 656 .285 A 400 4,9D1 1 4 57 27 3.03 2 30 56.45 25 + .010 14.337 .315 + .00 B 401 4,967 5 14 58 55 1.40 60 37 44.43 32 + .027 14. 246 .150 — ..33 A 402 5,031 1 5 15 9 08 2.51 29 33 55. 16 23 + .033 13.549 .276 + .04 B 403 5,033 1 e 10 16 2.16 42 34 24.70 36 — .025 13.530 .239 .00 B 404 5,048 5 13 34 2 69 20 58 4. 30 33 — .012 13.316 .298 + .10 A 405 5,061 5 15 40 2.48 30 29. 01 19 -.049 13. 177 .280 — .01 A 400 5,072 1 5 17 29 2.40 33 19 12.91 20 + .004 13. 057 .272 — .01 A 407 5,085 5 20 47 2.78 15 48 29.54 21 + .005 12. 837 .317 + .00 B 408 5,091 '• 5 20 50 .99 63 43 37. 51 31 — .090 12.834 .116 + .09 B 409 5,113 1 e 25 57 1.91 48 5 2.80 33 -.010 12. 486 .224 + .40 A 5,119 5 27 24 3.08 — D 49 10. 85 30 — .046 12.387 .359 + .05 B «1 5. 147 5 15 29 25 .84 64 34 19.31 18 + .078 12. 248 .103 — .31 B 412 5, 152 6 31 28 2.78 15 27 31.83 26 + .013 12. 105 .328 + .17 B 413 5, 153 5 31 31 2.76 16 28 36.90 33 .000 12. 102 .326 + .00 B 414 5, 177 5 34 49 1.91 47 9 13. 29 31 - .133 11.871 .229 + .11 A 415 5,214 4 41 12 2.91 7 4130.21 28 -.057 11.416 .356 + .29 A 416 5, 244 4 45 4 2.51 26 23 56.98 21 — .078 11. 136 .311 + .02 B 417 5,248 5 45 1 1.44 55 42 27.24 28 + .010 11. 139 .179 H- .06 A 418 5, 259 4 47 1(1 2. 26 35 59 33. 04 23 — .357 10. 983 .280 + .06 B 419 5.273 e 49 40 2.05 20 37 39. 99 34 + .047 10.788 .330 + .21 A 420 5, 284 3 51 28 2.76 16 51.73 13 -1.286 10.666 .343 — .03 B 421 5,298 5 15 51 52 2.02 42 52 49.22 20 .000 10.630 .254 -.12 I B 422 5.3,3 5 55 14 1.41 55 3 18.23 26 + .118 10.386 .183 — .23 A 423 5.338 1 4 .59 26 1.87 46 20 11.81 19 -.064 10.069 .239 -f .09 A 424 5, 366 6 IB 3 10 2.89 8 49 18.02 30 — . 012 9.778 .372 .00 A 425 1. ec5,367 6 3 12 2.70 17 20 .5.44 18 — .011 9.783 .350 + .00 A 420 5, 388 4 5 22 . 1.89 45 13 5.51 17 H- .043 9.617 .246 — .01 A 427 5, 411 5 7 51 2.19 30 42 14.50 24 — .040 9. 426 .286 .00 A 428 5,448 6 13 55 2.48 26 9 35.06 29 -.007 8.954 .327 + .01 UNITED STATES AND MEXICAN BOUNDARY. Mean declinations of latitude stars— Coutimied. 45 Class. .0. B. A. C. Mag. AK. 1892. Annual variation. Declination, ^™'' 1892. «^ !;J?'® I'roper 2.' '"»«»"■ 5? Sec. var. " ;.. m. s. s. . „ „ „ A 429 5,456 5.0 16 36 + 3.03 116 58.91 ±0 26 +0.035 —8.743 +0.404 +0 09 A 430 5,512 2.7 22 32 .81 6145 31.15 15 + .050 8.273 .110 05 A 431 5,545 5.0 16 28 12 - .15 69 6.47 14 + .030 7.820 - .014 I 07 B 432 0.1 32 14 +3.21 1.63 — 6 19 12.82 40 20 -.010 + .021 7.493 7.201 + .438 .225 J 02 10 A 5,596 5.0 35 49 49 8 22.74 + B 434 0.3 43 10 2.76 13 46 57. 25 29 — .010 6.597 6.480 .385 : 23 B 435 5,647 5.9 44 36 2.77 13 27 0. 03 31 - .008 A 436 5,693 5.5 48 52 2.27 31 52 50. 33 20 — .019 6.124 .319 _ 03 A 437 5,731 3.7 56 9 2.29 31 5 8.41 16 + .032 5.514 .324 _ 01 B 438 5.0 17 1 44 2.54 22 13 50. 04 30 .- .045 5.043 .302 + 10 B 439 5,790 0.1 4 15 1.95 40 39 20. 21 22 — .031 4.830 .279 _ 11 A 440 5,828 3.1 lU 36 2.46 24 58 0.58 18 — .153 4.289 .354 + 02 A 441 5,847 4.8 17 13 57 2.07 37 24 17. 73 18 + .084 4.003 .208 03 A 442 5,871 5.7 17 18 1.70 40 20 48. 07 19 + .032 3.715 .245 + 13 B 443 5.8 19 41 2.68 16 24 2. 76 24 — .040 3.509 .388 .112 30 46 B 444 5,917 5.7 2t 18 .77 60 8 21. 14 27 + .070 3. 112 ; B 445 5,919 5.8 25 56 3.01 2 48 21.40 25 + .032 2.969 .436 30 B 446 5,944 5.9 29 42 2.70 41 19 11.89 34 - .060 2.644 .277 _ 29 B 447 21 3 50. 24 48 38 54. 59 34 22 -.024? + .051 2.498 2.287 .372 .228 34 11 A 448 5,075 5.8 33 48 1.56 + B 449 44 13 + .010 — .268 1.411 .398 — .157 14 02 A 450 6,047 4.5 17 43 51 -1.08 72 12 6. 18 + A 451 6,078 3.5 53 5 -r3.30 - 9 45 35.45 13 — .105 .605 + .482 + 05 A 452 6, 142 4.9 18 2 8 2.87 8 43 13. 49 28 + .033 + .187 .418 _ 09 A 453 0,157 4.4 4 8 2.50 20 47 51. 68 25 — .013 .362 .374 _ 08 B 454 6,185 0.0 8 10 1.22 54 15 15.70 23 + .245 .727 .177 _ 10 B 455 6,203 5.4 12 17 1.86 42 7 21.39 19 .000 1.074 .271 + 01 B 456 6,218 0.0 13 41 1.92 40 53 39. 20 31 + .079 1.197 .279 10 A 457 6,221 5.5' 15 44 2.53 21 54 50.69 26 -.051 1.375 .369 + 01 A 458 0,241 0.1 17 38 2.50 23 13 50.40 21 -r .082 1.542 .263 00 A 459 C.251 4.1 19 6 2.55 21 43 14.97 15 -.257 1.069 .369 + A 460 6,208 5.0 20 40 1.97 39 26 54.48 21 — .001 1.806 .286 08 A 461 0,297 4.4 18 22 18 - .85 71 16 48.57 13 + .021 1.949 - . 125 + 03 A 462 4.1 29 20 +3.20 — 8 19 9.02 14 — .307 2.550 1- .472 ^_ C2 B 403 0,373 0.7 37 .73 00 30 38. 83 28 + .053 3.231 .104 + 47 A 464 6,379 5.1 39 23 3.03 1 57 1.32 25 — .026 3.429 .434 + 03 B 465 6,404 5.9 42 46 1.92 41 19 32. 92 28 + .003 3.720 .273 38 B 466 0,428 5.9 45 25 1.58 48 37 38. 50 19 + .053 3.948 .225 00 B 467 6.1 47 5 2.75 2.50 13 50 12. 52 21 17 43. 02 33 25 — .010 — .006 4.091 4.140 .390 .364 52 02 A 468 0,438 5.3 47 40 A 409 6,466 4.4 50 44 2.10 36 45 42. U 24 + .020 4.402 .297 _ 04 B 470 0.476 5.8 51 50 1.59 48 43 27. 50 34 — .133 4.506 .224 _ 30 B 471 5.8 18 .15 21 2.44 20 4 53. 11 31 — .003 4.797 .342 _ 31 A 472 0,528 3.1 19 27 2.75 13 42 11.54 17 — ■ . 089 5.228 .386 _ 04 A 473 6,552 5.4 3 42 2.94 5 54 13.83 22 — .064 5.503 .410 _ 03 A 474 6,583 5.4 9 38 1.13 56 40 30. f8 15 + .045 5.999 .155 + 02 B 475 6,002 5.8 13 9 2.54 22 49 52. 35 31 — .011 6.203 .349 _ 23 B 476 6,624 5.4 15 21 1.38 40 9 40.49 31 + .005 6.475 .274 _ 09 A 477 6,637 5.4 18 26 2.46 20 3 19. 15 21 - .013 6.720 .335 + 05 A 478 6,602 4.0 20 7 .32 65 30 23.57 15 + .030 6.868 .041 _(. 03 B 479 6,651 6.7 20 14 2.15 30 14 19. 39 44 + .084 6.677 .292 _ 39 A 480 0.674 4.5 21 13 2.49 24 26 47.26 17 — .102 7.203 .338 _ 06 A 481 6.679 5.4 19 25 1 3.14 — 3 48. 78 15 + .004 7.269 .424 — 02 B 482 6,7U O.G 29 51 2.09 38 31 37. 13 32 + .037 7.661 .280 _ 23 B 483 0,723 5.8 31 32 1. i,5 51 17. 87 16 — .190 7. 708 .205 — 17 A 484 0,734 4.7 33 33 1.01 49 58 15. 82 13 + .239 7.900 .214 + 08 A 485 6,739 4.4 35 10 2.68 17 45 56. 89 22 — .012 8.098 .355 _i_ 11 A 486 0,749 5.7 37 29 2.82 11 34 21.73 21 + .017 8.275 .372 + 17 A 4S7 6,759 6.2 39 33 2.79 13 2 37.91 32 — .017 8.439 .368 _ 01 ^ 488 0,779 3.0 41 36 1.88 44 52 1. 90 15 + .035 8.601 .363 + 10 489 0,805 5.6 45 51 2.86 10 8 44. 10 24 — .149 8.936 .369 + 10 46 UNITED STATES AND MEXICAN BOUNDARY. Miiin decUiiatiuns of lalitude s/((i-s— Continued. 0>a.. No. B.A.C. Mag. AE.1892. Annual variation. Beolination, ^"j! 1892. f^, able or, 2. ^IZl Annual preces- Sec sion. W. A5 A 490 6,B24 5.3 h. m. s. 47 55 + 1.51 52 42 50. ,57 +0 22 —0 075 + 9.097 +0 190 +0.03 B A 491 492 0.3 5.2 19 48 52 2.99 2.14 4 7 16. 09 38 11 59.30 37 19 + 020 007 9.104 9.414 385 274 + .11 .00 6,849 B 493 6,807 5.4 53 52 1.15 58 33 27.41 19 _ 018 9.558 144 — .01 B A 494 495 5.8 54 21 57 10 2.38 2.54 30 4127.44 24 30 3.46 29 14 + 006 001 9.595 9.811 300 318 — .44 — .06 6,882 A 496 6,883 5.4 57 20 2.54 24 38 8.49 23 + 001 9. 832 318 + .01 A 497 6,893 5.8 58 52 2.93 6 58 24.84 21 + 036 9.940 317 + .06 B B 498 499 5.8 6.3 20 22 2 54 2.35 1.36 31 54 45 38 56 1 44. 30 30 22 + 006 068 10. 054 10.246 293 167 — .08 + .40 6,924 B 500 6,930 6.1 3 23 .76 03 34 45.99 32 + 043 10. 282 091 + .01 A 601 6,937 5.2 20 5 25 • 2.23 36 31 in. 05 21 + 050 10.437 272 + .05 A 502 0,934 3.1 5 44 3.10 - 1 8 29.64 12 + 014 10. 457 380 — .06 A 503 6,944 0.0 7 29 2 61 26 9 23. 08 24 — 027 10. .588 308 — .08 A 501 6,952 5.1 9 17 2.78 14 52 8.06 19 + 081 10. 721 337 — .CO B 505 6,966 5.0 10 41 2.54 25 16 44. 06 31 _ 015 10. 825 307 — .35 A 506 6,968 5.0 10 50 2.59 23 10 43. 94 31 _ 014 10.836 314 — .04 A 507 6,983 4.5 12 8 1.85 47 22 67. 16 19 — 008 10. 931 222 + .04 A 508 6,990 var. 13 48 2.21 37 41 49. 81 25 + 003 11.064 264 + .09 B 509 7,017 6.0 16 28 .61 66 30 23 27 23 + 284 11.247 059 — .17 A 510 7,024 5.8 17 48 1.01 61 54 52. 18 20 + Oil 11. 344 117 — .08 A 511 7, 022 2.6 20 18 21 2. 15 39 54 40.33 13 + 020 11.383 254 — .03 A A 512 513 6.2 6.1 19 7 22 46 3.06 3.14 43 9.27 — 3 42 51.33 27 20 + 006 005 11. 439 361 368 — .17 — .07 7,016 A 514 7,085 5,0 26 43 1.86 48 35 19.01 19 + 007 11.978 212 — .01 A 515 7,098 4.0 27 46 1.02 02 37 51. 79 14 _ 027 12.052 113 + .01 j^^ 510 7,091 5.0 27 59 1.85 48 51 20.71 20 _ 040 12.067 211 + .09 A 517 7,107 4.7 30 16 2.80 14 18 0.46 21 _ 002 12. 225 319 + .04 A r,is 7,121 3.5 32 29 2.81 14 13 10 62 17 _ 031 12. 379 317 .— -02 A 519 7.137 ■ 6.0 33 38 2.83 12 56 9. 83 27 _ 006 12.458 319 — .03 B 520 7, i:i8 5.3 33 53 3.07 6 25. 35 22 _ 010 12.475 346 - .03 A 521 7,182 5.5 20 38 53 1.85 49 57 8. 02 19 _ 002 12. 815 202 — .t2 B 522 7,189 6.9 39 36 1.49 56 59 47. 97 31 _ 022 12.862 160 — .17 A 523 fc U 7,200 3.9 41 39 2.78 15 44 6.87 18 _ 196 13. 000 304 + .03 A 524 7,206 5.7 42 27 2.97 5 36 42. 13 10 + 001 13. 053 324 + .07 A 525 7,213 4.7 43 12 2.33 36 5 38.42 17 + 018 13. 103 252 — .02 A 526 7,246 4.9 47 30 2.57 26 41 33.80 21 _ 074 13. 386 274 .00 A 527 7,257 5.6 50 29 2.86 12 9 20.41 21 + 010 13.579 301 + .09 B 528 7.268 6.0 52 11 2.02 47 13.83 33 + 004 13.688 210 — .03 B 529 7.278 5.8 53 1.90 50 18 50. 00 31 007 13.740 195 .00 A 530 7.276 5.3 53 41 3.01 3 52 46. 20 21 _ 139 13.783 312 — .10 B 531 6.0 20 55 32 ■ 2.74 18 54 35. 19 34 _ 058 13. 900 2S2 -.29 B 532 7,310 5.8 50 46 1.47 59 59. 25 14 __ 002 13. 978 148 •1- .05 A 533 f. 11 7,302 6.4 66 63 2.96 6 45 19. 94 27 _ 012 13.985 300 — .04 B A 534 535 5.9 4.0 69 10 21 1 1.65 2.18 56 14 35. 37 43 29 49. 08 20 15 - 006 008 14. 128 14.241 164 218 + .13 + .02 7,333 A 530 7,350 4.5 5 5 2.95 9 41 47.87 21 — 167 14.491 288 + .03 A 537 7,351 6.1 5 16 2.95 9 36 30. 92 24 + 019 14. 502 288 - .02 B 538 7 365 5.8 6 55 1.85 53 7 19.84 23 _ 014 14. COl 178 — .04 A 539 7^380 4.1 10 25 3.00 4 48 5. 47 It _ 078 14.810 2S8 + .03 A 540 7,398 4.5 13 10 2.35 38 50 31. 32 21 _ 013 14.971 222 + .08 B 541 7,402 5.0 21 14 25 2.26 43 29 29.52 26 _ 012 15. 043 209 + .08 B 542 7,410 5.9 16 11 2.69 23 24 4. 42 28 _ 1.30 15.145 153 — .42 A 543 7,417 5.9 16 16 1.66 58 9 59. 35 20 _ 024 15. 150 200 — .05 A 544 7,418 4.3 17 5 2.77 19 20 33. 38 19 + 075 15. 196 257 + .12 ]i 545 7,437 5.8 19 7 2.69 23 4S 37. 19 28 .)- 030 15.311 247 -.29 A 546 7,440 5.9 19 39 3.01 — 4 1 11.00 32 _ 068 15. 347 288 — .30 A 547 7,482 5.0 25 41 1.71 06 20 16. 04 19 _ 042 15.676 100 -.04 B B 548 549 6.0 0.1 25 56 30 44 2.90 2.00 11 39 47.20 51 13 1.81 24 - 004 008 15. 690 15.948 257 176 — .30 + .29 7,512 B ,150 7,528 5.9 33 59 2.79 19 46 41.55 38 4- 006 16. 119 236 — .16 n 551 7,630 6.1? 21 34 3 2.00 53 33 21.21 25 _ 018 16.122 167 — .01 A 552 7,542 5.1 35 1 1.61 61 35 41.19 18 - 012 16. 173 132 — .09 UNITED STATES AND MEXICAN BOUNDARY. Mean declinations of latitude stars— Continned. 47 (JIass. No. B.A.C. Mag. AE.1892. Annual variation Declination, P™b\l"« SS. Annual preces- Sec var. A6 h.m.s. ,. o , „ „ „ A 553 7,544 5.5 35 57 + 2.35 42 47 0.76 ±0 18 +0.0U + 16.220 +0 194 +0.04 A 554 7,546 5.9 36 40 3.06 47 36. 76 20 _ 020 16.257 255 _ 26 A 555 7,561 2.4 38 53 2.95 9 22 48.00 17 ^ Oil 16. 370 241 00 B 556 p r 7, 560 5.6 38 58 2.47 37 47 21.21 22 + 001 16.374 201 _ 11 B 657 7.586 6.8 41 29 2.72 25 3 48.33 38 + 038 16. 500 218 + 17 A 558 7,587 5.6 41 45 3.04 2 11 11.80 25 _ 010 16.514 245 00 A 559 7,605 5.9 44 14 I 77 60 U 29.53 28 _ 001 16.636 137 _ 03 A *d60 7,631 6.0 48 22 1 75 55 17 20. 91 32 ._ 025 16.835 153 _ 31 jj 561 6.4 21 54 25 1 53 65 38 27. 51 30 , 003 17. 117 110 _ 11 B 562 6.8 54 38 54 65 37 24, 50 30 006 17. 127 110 20 A 563 7,660 5.9 55 34 3 07 5 10. 85 23 _ 001 17. 169 224 4 05 A 564 7,662 5.9 55 48 2 98 7 44 17. 02 28 _). 005 17.179 217 _ 02 A 565 7,672 4.7 57 44 3 10 —2 40 35. 69 21 _ 002 17. 266 222 _ 01 A 566 7,685 5.8 59 14 3 09 -1 25 42.43 21 _ 031 17. 333 218 4_ 03 B 587 7,699 5.7 22 39 1 79 62 35 39. 31 27 + 034 17. 394 123 + 29 A 568 1 1.11 7,700 4.6 40 1 73 64 6 5.57 17 4. 065 17. 395 116 4. 03 A 569 7,693 5.7 41 2 71 28 26 21.53 21 _ 010 17.390 189 -f- 07 A 570 7,707 5.8 1 44 1 82 62 15 31.46 17 + 045 17.441 124 + 04 B 571 7,733 6.1 22 5 24 2 83 20 20 50. 16 28 _ 008 17. 598 190 _ 26 A 572 7,749 3.7 7 6 2.07 57 40 8.01 15 _ 006 17.669 135 _ 01 B 573 7, 753 5.6 8 1 2.65 34 419.97 30 _ 041 17. 706 173 — 27 B 574 7,770 5.8 10 12 2.51 42 25 5.58 25 _ 020 17. 795 161 _ 08 A 575 7,788 5.5 15 1 3.02 6 14 48. 43 20 _ 005 17. 986 187 — 03 A 576 7,795 3.7 16 5 3.10 -1 55 63. 27 13 + 017 18. 026 190 _ 03 A 577 7,807 0.1 18 28 2.86 20 18 9. 17 20 _ 019 18. 117 171 _( 13 A 578 7,837 5.7 23 37 1.91 64 34 53. 59 25 _ 012 18. 305 106 + 01 I! 579 7,850 4.8 25 50 2.09 42 34 11. 16 27 _ 002 18.384 143 _ 00 580 7,868 4.0 29 48 3.08 —0 40 26, 85 12 _ 053 18.520 164 + 05 A 581 7,893 5.9 22 33 30 2.90 18. 57 48. 21 23 ^ 094 18.646 148 + 09 A 582 7,902 5.3 34 49 2.11 63 1 22. 83 38 039 18.6S4 [ 105 — 03 A 583 7,906 4.9 35 47 2.02 43 42 44.52 22 _ 016 18.714 129 _ 02 B 584 7,931 0.1 39 13 2.70 38 53 58. 56 25 - 030 18 820 128 _ 06 A 585 7,945 4.0 41 20 2.88 22 59 50. 53 15 _ 004 18 883 133 _ 03 A 580 7,9.18 3.8 44 47 2.89 24 1 52.84 10 - 042 18 983 126 - 04 1! 587 17, 903 ( 0.5 I 7.0 } 45 20 2.01 67 59 50. 52 23 + 069 18 998 087 - 12 ]! 588 7,984 5.9 49 10 2.73 39 48 4. 20 30 + 039 19 103 113 _ 70 V. 589 7,980 5.9 49 35 3.11 -5 33 47.57 22 000 19 114 129 _ 03 A 590 7,993 6.5 61 42 3.10 —5 23 13. 91 17 + 005 19 169 124 + 01 B 591 7,999 .5.3 22 52 18 2.04 48 6 24.78 21 _ 030 19 184 104 + 02 B 592 8,013 6.7 54 44 2.44 59 14 9.34 24 _ 021 19 245 ] 091 — 04 A 593 8,031 4.6 58 23 3.05 3 14 18.50 20 _ 015 19 332 110 00 A 594 8,034 2.2 69 23 2.98 14 37 27. 23 16 _ 030 19 355 105 + 07 B 595 8,077 6.4 23 6 40 2.34 66 39 21.14 33 Jf. 022 19 492 073 + 36 B 596 8,094 5.4 10 3.09 —4 5 0.53 28 + 005 19 578 089 - 07 A 597 8.105 3.8 1134 3.10 2 41 31.76 13 4. 017 19 607 065 + 04 B 598 6.7 15 34 2.63 59 41 0.43 33 031 19 677 084 _ 13 599 8,158 6.9 19 13 2.71 50 56 33. 05 23 _ 013 19 736 061 + 05 A 600 8,162 5.5 20 2 2.64 61 41 23.38 15 — 021 19 749 058 + 02 A 601 8,169 5.0 23 21 24 3.07 39 51. 60 15 _ 102 19 769 066 _ 10 A 602 8,177 4.5 22 29 3.07 5 47 8.77 18 _ 045 19 785 064 _ 07 B 003 8,188 5.0 25 3 2.75 57 57 12.92 28 + 003 19 820 052 — 12 A 604 8,195 5.7 25 59 2.94 38 38 34.48 15 _ 077 19 832 054 + 02 B 005 6.1 28 30 3.00 20 14 40. 94 31 _ 014 19 864 062 _ 24 B A 606 007 6.3 4.1 30 32 32 50 2.99 2.93 23 57 47.44 42 40 12.20 31 16 - 023 012 19 19 912 048 042 + 46 00 8,229 A 608 8,233 4.2 34 24 3.08 5 2 27.02 14 _ 443 19 928 040 _ 02 A 609 8,243 4.8 36 32 3.06 1 11 8.42 19 _ 137 19 948 038 _ 02 A 610 8,262 5.7 40 52 3.06 2 53 16.02 18 _ 023 19 983 029 + 08 A _^ 8,279 5.8 23 43 36 -2.89 61 36 61.20 19 - 010 20 001 022 00 t Middle point botv 48 UNITED STATES AND MEXICAN BOUNDARY. Mean declinations of latitude stars — Continued. Class. No. B.A.C. Ma. AR. 1892. Annual variation. Declination, 1892. Probable 1892.' ,^S Annual Sec. var. .i S h. m. .1. e. o , .. „ „ „ B (-.12 8,280 6,5 43 36 +2.91 59 22 41. 61 +0.23 —0. 003 + 20.002 + 0.021 — 01 A ei3 8,295 5.9 46 26 3.07 2 19 47.80 .19 — .011 20. 018 + .018 00 A 6U 8,296 5.9 46 54 3.04 21 4 13.40 .26 - .018 20. 020 + .018 + 10 ". 615 616 6.0 48 28 50 6 3.06 00 15 9.10 7 37 20. 34 .30 — .006 - .007 20. 027 20. 034 + .014 + .010 — 00 04 8,315 B 617 S,322 5.8 51 42 3.00 55 17.11 .19 — .024 20. 040 + .007 — 31 A 618 8,330 5.0 53 32 3.01 55 9 13. 44 .20 -.015 20. 045 + .004 - 04 li 619 8,345 6.0 56 12 3.05 41 45 50. 51 .35 — .016 20.050 0.0 - 01 A 620 8,354 5.0 56 58 +3.06 7 53 8. 39 .21 — .027 20. 051 -.002 + 01 B 621 6.3 23 57 41 +3.07 10 57 8. 86 .27 -.037 + 20.052 —.004 — 30 Authorities for star cataloyue. First column : Number in catalogue. Second colunni: Authority for proper motion. — "Brad. 11'" denotes, for example, tli.at the Proper Motions are from Auwers's liradley. and that Bradley has eleven observations. "Piazzi and others'' denotes that all available observations including and since Piazzi have been used. No statement in column 2 denotes in general that the old observations are rather scanty, chiefly zones. Tliird column : Authorities used in the star iilaces em]doyed on the boundary. — They jire alil)reviations of the names of the observatories, witb dates, in 1800- 190U. "Xrnl." denotes Yarnalls' Catalogue, 3d edition. For Oxford, Greenwich, Washington, the observations not yet catalogued have been previously reduced to some mean epoch; for example. No. 002 (.V.X. .\m. Ephemeris star) was on revision brought up from Washington volumes for many years to tlie mean epoch 1876, 1884, and tlio Gri'eiiwich volumes for 1887-1890 wore simi- larly treated. Fourth column : Observations added on revision. No. Authorities for proper motion. Authorities used for declinations in computing latitudes on the boundary. Observations added on revision. Bradley 7 Berlin Jahrbuch, Pulk. 55, Oxford 60, Cambridge. Rome, Pu'k. 75, Grnwch. 80. Bradley 5 Pulk. 55, Paris 60, Glasgow, Brussels, Grnwch.64,72,80, Leijizig, Leiden, Rome. Pulk. 56, Brsls., Paris 75. Grnwch. 80, 89 Bradley 5 Pulk. 55, Yarnall, Oxfrd. 60, Brsls., Grnwch. 72, 80, Camhr., Paris 75, Rome, Pulk. 75. Arglndr. 3-250... Paris 00, 75, Bonn, Pulk. 62, 75, Trul., Grnwch. 04, Kdinboro, Glsgw., Melbourne, Albany Zone, Gotha. Brad, aud later auths. Ednbro., Brsls., Pulk, 55, Oxfrd. 70, Grnwch. 72, A. G. Christiania Z Br.id. 5 Paris 45, 00, Grnwch. 00, 72, 80, 87, Pulk. 55, Cambr., Rome, A. G. Hel- singfors, Gotha. Pulk. 55, 02, 75, Grnwch. 00, 64, 72, 80, 88. Brsls., Trnl., Paris 75, Glsgw., A.G.Albny.,Rome. Brill 1 13 ' End 4 Pulk 55 V'rnl Grnwch 64 72 89 Paris 75 Rome 14 1 Br.id. 11 Brln. .Jrbh.. Pulk. 55, 75, Oxfrd. 60, Yrnl., Paris 60, 75. Glasgow, Grnwch. 80, 88, Auwers's 303 Stars Auwers's 'l auths. auths. Brad. 14 Pulk. 55, Paris 60, Yrnl., Grnwch. 64, 72, 80, 89, Brsls., Gilttingen, Glsgw., Paris 75, Auwers's 303 Stars. 21 Brad. 15 ... Brln. Jrbh., Yrnl., Oxfrd. 60, Paris 60, 75, Glsgw., Cambr., Pulk. 75, Rome, Grnwch. 80, 88. 23 Brad. Pulk. 55, Bonn, Grnwch. 64, 72, Lpzg., Leidn., Cambr., Rome, Paris 75 24 Brad. Land later.. Pulk. 55, Rome, Oxfrd. 70, Brsls., A. G. Helsingfors, Grnwch. 72, Berlin . . UNITED STATES AND MEXICAN BOUNDARY Authorities for star catalogue — Continued. 49 I Autliorites for liiojier motion. Authorities used for declinations in i boundary. 27 Brad. . 28 : Brail. 3 . 29 Brad. 3 . 30 Brad. 3 . 31 Brad. 8 32 Piazzi and others Brad. 10 Brad.3 Brad.4 Brad. 1 and later. . Brad. (Auwer's) and others. I!rad.4 Brad.l Auwers'sBradley. others. Brad. 4... 43 I Bra<1.3... Pulk. 55, Ornwch. 60,72, Li)zg.,Leidn.,Eome :, Pulk. 55, Trnl., Ednbro., Grnivch. 64, Brsls Brlu.Jrbh.,Pulk.55, 75, Cambr., Rome, Paris 75 Pulk. 55, Paris 60, Grnwch. 64, Glsgw. 75, Armagh Pulk. 55, Paris 60, Grnwch. 64, 72, 80, Rome Brln.Jrbh., Yml., lirsls., Canibr., Paris 75, Rome, Pulk. 75, Grnwch. 80,88. Pulk. 55, Trnl., Grnwch. 60, 80, 88, A. G. Camlir., Paris 75, Rome, Gotha, Prime Vertical. Pulk. 55, Oxfrd. 60, Brsls., Trnl., Grnwch. 64, 72, Paris 60, 75, GLsgw., Rome, A. G. Albny., Gotha, Cincinnati. Brlu. Jrlili., Pulk. 55, 62, 75, Oxfrd. 60. Paris 60, 75, Trnl., Drsls., Glsgw., Rome, Grnwcli. 80, 89. Pulk. 55, Oxfrd. 60, Grnwch. 64, Brsls., Paris 75, Rome, Cinn Brlri. Jrbh., Pulk. 55, 75, Rome, Grnwch. 80 Trnl., Glsgw., Pulk., Brsls., Grnwch. 72, Cambr., A. G. Albny Pulk. 55, Trnl., Oxfrd. 60, Brsls., A. G. Hlgfrs., Grnwch. 72, Rome, Brln . Pulk. 55, 75, Paris 60, Brsls., Glsgw., Grn wch. 64, 72, 80, Rome Brln. Jrbh., Oxfrd. 60, Paris 60, Tarnl., Brsls., Cambr., Rome, Pulk. 75, Grnwch. 80, 88, Rome. Pulk. 55, Grnwch. 72, A. G. Helsingfors, Pulk. 73 Pulk. 55 Brsls., Paris 75, Grnwch. 80 Brad.3. Brad.3. 46 I Brad. 3 47 ( Brad.4 48 ■ Arglnd.and later Pulk. 55, Paris 75, Grnwch. 72, Rome, Cambr.. Ann Arbor, Grnwch. 80, 87 Brln. Jrbh. , Oxfrd. 60, 75. Paris 60, 75, Trnl., Bonn, A. N., Washington 68, Boss, Glsgw., Cambr., Pulk. 75, Rome, Grnwch. 80, 89, Glasgow 90. Pulk. 55, 75, Oxfrd. 60, Paris 00, Grnwch. 64, 88, Brsls., Rome Pulk. 55,75,Trul.,Oxfrd. 60, Paris 75, Brsls., Grnwch. 64,72, 80, 88, Glsgw., A. G. Albny. Pulk. 55, Oxfrd. 60, Grn wch. 64, 80, Brsls., Rome, Paris 75 Pulk. 55, Brsls., Grnwch. 04, 72, 80, A. G. Christiania., Rome Bonn, Brsls. A. G. Chrstana., Pulk. 75, Cinn ■I Brad. 5 Brad.O Pulk. 55. Grnwch. 04, Brsls., Rome, Paris 82, Grnwch. 87 ^'"'"'- 5 ' Oxfrd. 60, Brsls., Pulk. 55. Grnwch. 64, 80, 89, Rome. A. G. Helsin"for.s Brad.l ] Pulk. 55, Grnwch. 64, Rome ° ^™'- Smwch. 60, 64, 72, Oxfrd. 60, Pulk. 55, 75, Braid., Giittingen, Cor- doba, Pulk. 75, Paris 75, Glsgw., Karlsruhe. Pulk. 55, Paris OO.Oxfrd. 60, Brsls.,Grnwch.64,Trnl.,Auwers's303 Stars Pulk. 55, 62, Grnwch. 60, 64, 72, 80, 88, Trnl., Brsls., Paris 75, A.G. Albny., ^r-ii.l I Oxfrd. 60, Pulk. 55, Grnwch. 64, Brsls., A.G. Helsingfors ^"•ad-S-- Pult. 55, Paris 60, 75, Grnwch. 64, Oxfrd. 65, Rome ..."^ ^'''"l-ll rulk.55,75, Grnwch. 60, 64, 72, 80, Paris 60, 82, Trnl., Rome ^'^'^- ^ r""'- 55, Trnl., Pulk. 62, Grnwch. 64,Gottingen, Paris 75,Cordoba,"K3rls. 35rad.4 Pulk. 5-,, Oxfrd. 60, Brsls., Grnwch. 64, Rome ' Pulk. 55, Paris 75. Grnwch. 80 Brad.l5 1 Brln. Jrbh., Oxfrd.60, Pjiria G rnwch. 80, Pulk. 90, 91 . I Tulk. 55, Grnwch. 60, 80, Paris 60, Glsgw., Rome ^'''"'■5 Pulk. 55, Grnwch. 60, 64, 72, SO, Brsls., Paris 60, Trnl., Rome ^'"'"l-S Pulk. 55, Grnwch. 60, 72, 80, Trnl., Brsls.. Paris 75 Bri^- " Pulk. 55, 75, Oxfrd. 60, Brsls., Cambr., Komi Brad.7 .... Brsls., Trnl., Cambr., Rome, Pulk. 75, Paris 75, Grnwch. 80 Pulk. 55, Grnwch. 64, 72, Rome, Paris T". B™'! * I'nlk. 55, Paris 60, 75, Grnwch. 04, 7.', i I'»lk. 55, Grnwch. 64, Glsgw., Pari,, T.i ^rad. 8 Pulk. 55, 62, 75, Oxfrd. 60, Grnwch. CO, Glsgw., Rome. ii'-^^i Brln.Jrbh., Oxfrd. 60, Trnl., P.ari8 Rome, Grnwch. 80, 88. Pulk- 55, 75, Grnwch. 64, 80, Br.sls., Paris, 75, Glsgw.. Ci . Glsgw. 90. . Trnl., Paris \ ilsgw., Cilmbr., 50 UNITED STATES AND MEXICAN BOUNDARY. Authorities for star cataloyue — Continued. No. 72 73 74 75 76 77 78 79 80 81 82 8:i 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 100 107 108 109 110 111 112 113 114 115 116 117 Authorities for proper motion. Anthorities used for declinations in computing Latitudes on the boundary. Observations added ou revision. r«llj.55,A.G. Helsingfors. Kome, Brln., Grnweh. 80, Pulk. Prime Ver- tical. Paris 60, 75, Brsls., Oxfrd. 64. Yrnl., Glsgw.. Pulk. 75, Crnwch. 72, Gotha85,A.N. Pullr. 55, 75, Konigsb. 61, Bonn, Paris 75, BrsLs. 05, Cordoba, Grnwch, 80, Karlsruhe. Grnwch 60 80 Pulk 55, Brsls., Trnl., A. G. Hlgfr8.,Eome Pulk. 85. Glsgw. 90. Wushgln. I'HiiiB Piazzi.etc Brad 12 Brln. Jrbh., Oxfrd. 60, Paris 60, 82, Brsla., Trnl. Cambr., Rome, Pulk. 75, Grnwch. 80, 88. Groombridge and others. Brad.6 Piazziand others. Oxfrd. 60, Pulk. 55, Brsls., Grnwch. 64, 72, A. G. Chriatiania, Rome Paris 60, Brsls., Pulk. 75, Cambr., Ann A rbor, Grnwch. 80 Brln. Jrbh., Pulk. 55, 62, 75, Oxfrd., Trnl., Paris, SO, 75, Glsgw., Cambr., Rome, Grnwch. 80, 88, Auwers's 303 Stars. Pulk. 55. 75, Paris 60, Grnwch. 60, 80, Oxfrd. 60, Brsls., Trnl., Rome Br.adlan 80 Brsls Gl8"w Rome Brln. Jrbh., Brsls., Pulk. 75, Cambr., Rome. Gmwch. 80, 87 UNITED STATES AND MEXICAN BOUNDARY. Authorities for star catalogue— Cout'mned. 57 Authorities for Authorities used for declination in couiputiDK latitude proper motion. boundary. '' Brad. 4. Grmbrdg., etc Lalande, etc . Brad.2 , Lalande and others Grmbrdg. a others. Brad.2 Brad.2 Arglndr. revised . Arglndr. revised. Piazzi and others Brad.2 Groombridge and others. Brad.2 Groombridge and others. Piazzi and others Brad.3 Brad.3 Brad.2 Pulk. 55, 75, Brsla., Gmwch. 64, 72, 80, 8«, Washgtn. 70, Glegw., Rome. Palk.55, 7.5,Glsgw.,A.G. Albny., Gmwch.87 Brln. Jrbh., Trnl., Cambr., Glsgw., Pnlk. 75, Eome, Grnwch. 80. 87 . . , Brln. .Jrbli. crctd. for precsu., Pulk. 55. 75, Carabr., Eome, Grn-n-ch. 80 Glsgw., Kr.sls., A. G. Leidn., Rome, Amgh. 75, Brln. 88 Brln. Jrbh., Pulk. 55, 75, Brsls., Cambr., Brln., Eome Amgh. 75, Cambr., Pulk 75, Gmwch. 80 Eome, Grnwch. 80 Pnlk. 55, Yrnl., Grnwch. 60, 64, 72, 80, Eome Pulk. 55, 75, Grnwch. 80 Pulk. 55, 75, Brsls., Brln., Eome, Grnwch. 80 Pulk. 55, 75, Tml., Brsls., Grnwch. 64, 72, 80, Eome, Cinn erctd., Pulk. 55, 75, Oxfrd. 60, Brsls., Cambr., Eome, Grnwch. Brln.Jr Pulk. 55, Grnwch. 64, 72, 80, Brsls , Glsgw., Eome Palk. 55, Gmwch. 60, 80, 88, Glsgw., A. G. Albny., Eome Bonn, Pulk. 55, 75, Brsls., Cambr., A. G. Hlgfrs., Eome, Grnwch. Pulk. 55, Grnwch. 60, 72, 80, Brsls., Eome. Washgtn. 70, Eome, Grnwch. 88 Groombridge and Brad.2 Piazzi, Groom- bridge and oth- Brad. 1 and later.. Piazzi, Gi bridge an Brad. 2 and others Brad.2 Ednbro. 44 oldest authority. Brad. 2 Piazzi and others . Bratl.6 Pulk. 55, Trnl., Grnwch. 60, 80, Brsls., Rome Pulk. 55, 75, Trnl., Gmwch. 64, 72, 80, 88, Brsls., A. G. Leidn., Eome Pnlk. 55, 75, Yrnl., Grnwch. 64, 72, 80, A. G. Leidn., Rome, Glsgw. . . Brln. Jrbh., Pulk. 65, 75, Tml., Brsls., Glsgw., Eome Pulk. 55, Brsls., Ednbro., A. G. Hlgfrs., Cambr., Eome, Grnwch. 80. Glsgw., Rome Grnch. 90. Cinn.,Gls! Glsgw.-90. Greenwich 90. Pulk. 55, Grnwch., Yrnl., Gtngn., Brals., Glsgw Pulk. 55, Brsls., Grnwch. 72, 80, 88. A. G. Hlgfrs., Cambr., Eome. Brln. 88. Pulk.55,Grnwch.64, 87, Oxfrd. 75. Paris 83 Pulk. 55, Brsls., Brln., Home, Grnwch, SO Pulk. 55, Brsls., Washgtn. 70, Amgh. 75. Rome, Grnwch. SO . Pulk.55, Grnwch. 60, 80, 88, Brsls., Rome Brad. 1 and Liter.. Arglndr (revised) Brad. 7. Brad. 1 . Brad. 3. Brad. 4 427 I Piazzi and later.. 428 j Brad.2 429 Brad.3 430 Brad.6 431 ! Brad.lO 432 I Lalande and oth- Pulk. .M, 75, Grnwch. 60, 64, 72, 80, Brsls., Yrnl., Rnmi- Pulk. 5-% Brsls., A. G. Hlgfrs., Eome, Grnwch. 80 Kazan Prime i I tjcal. Pulk. 55, 75, Trnl., Grnwch. 60, 72, 80, 88, Oxfrd. 60, BrsLs., Eome I Grnch. 90, Cinn Pulk. 55, Yrnl., Brsls., GLsgw., Grnwch. 72. 80, Amgh. 75, Eome j Brlu., Jrbh., Oxfrd. 60, Brsls., Glsgw., Yral., Cambr., Pulk. 75, Cape 80, i Grnch. 89. 9(1. Eome. Grnwch. 80, 88. i Pulk. .55. 75, Yrnl., Brsls , Brln., Eome, Grnwch. 80 1 Brln. Jrbh.. Pulk. 55, 75, Washtn. 70, Brsls., Cambr., Rome. Grn\ Kazan Prin tical. , 88, Washgtn. 70, Cambr Pulk. .55, 75, Grnwch. 60, 80, Brsls., Rome . . . Pulk. 5.5, Brsls., Grnwc-h. 64, Glsgw., Rome . Pnlk. 55, 75, Yrnl., Oxfrd.60, Grnwch. 64, 72, 1 Glsgw., Rome. Brln. Jrbh., Oxfrd. 60, Brsls., Cambr., Pulk. 75. Rome. Grnwch. 88 . Pulk. 55, 75, Brsls., Yrnl., Green. 72, 80, Rome Pnlk.55, Grnwch. 64, Brsls., Oxfrd. 70, 75, Glsgw Pulk. 55, Grnwch. 60, 80, Brsls., A. G. Albny., Rome , Brln. Jrbh., Yrnl., Oxfrd. 60, Cambr., Eome, Pulk. 75, Grnwch. 80, 8 Brln. Jrbh.. Yml., Cambr., Pulk. 75, Eome, Gmwch. 80, 87 Pulk. 55, Amgli. 75, Crdba., Grnwch. 80 Greenwich 89, ! Greenwich 90. Greenwich 89, i S. Doc. 247 8 58 UNITED STATES AND MEXICAN BOUNDARY. Authorities for star catalogue — Continued. No. proper motion. Authorities used for declination in computing latitudes on the boundary. Observations added on revision. 433 Berlin 85, Green, wich 90. 434 435 430 DAgelet, Strove. Bra.1.2 Pulli. 55, 75,Tml., Brsls., Grnwch. 60. 72, 80, Paris 64, A.G. Leidn., Eome. 437 Brln. Jrbh., Oxfrd. 60, Brsls., Trnl., Glsgw., Cambr., Rome, Pulk.75. Grnwch. 80, 87, 88. Greenwich 89, 90. 438 Pulk. 55, Amgh. 75, Cambr., Grnwch. 80, Ann Arbr., Wasbgtn. 82 Glasgow 90. 439 Groombridge .and others. Brln. Jrbh. crctd., Pulk. 55, Yrul.. Cambr., Kome, Grnwch. 80 Brln Jrbh Trnl Oxfid 00 Brsls Washo-tn.70 Eome, Pulk.75 . Greenwich 89. Rome, Grnwch. 80, Washington, Prime Vertical. 442 443 Piazzi and otLers. Kadcliff and others Washington 81. Greenwich 89,90. Grnwch. fiO, 64, 72, 80, 88, Pulk. 55, Ednbro., Brsls., Eome, A. G. Hel- singfors. 445 Piazzi and others. Pulk. 55, Brsls., Glsgw., Yrnl.. Eome, A. G. Albny., Grnwch. 80 440 Groombridge and others. Pulk. 53, Grnwch. 60, 64, Washgtn. 70, Glasgow, Rome Glasgow 90. Pulk. 55, Trnl., Grnwch. 64, 87, 88, Brsls., Glsgw., Amgh. 75, Rome Greenwich 89, 90. Grnwch. 80, 88, Eome. 303 .Stars. Grnch 90 Pulk. 55, 75, Oxfrd. 60, Brsls., Washington 70, A. G. Cambr.. Rome, Paris 82, Gotha 85, A.N. Grnwch. 80. Groombridge and others. Greenwich 90 456 Groombridge jiud others. Pulk. 55, Grnwcli. 60, 80, Oxfrd. 60, Brussels, Rome 458 Brad.l Pulk. 55, Yrnl., Washgtn. 70, Brsls., Grnwch. 72, 80, Rome, Paris 83 Brln. Jrbli., Osfnl. 60, Brussels, Cambr., Glasgow, Pulk. 75, Eome, Green Grnch. 89,Glassow wich80.C.ape84. 90. Berlin 84 Brad 8 Brln Jrbh Pulk 55, 75 Cambr. Eome, Ginwcb. 80 Grncli.89. 462 Brad. 12 Pulk. 55, 75. Oxfrd. 60, Brsls., Yrnl., Grnwch. 04, 80, Cambr., Glsgw., Crdba., Cape 84. Cinn. Groombridge and otlit-rs. (Jreeunich 89 -ini Pulk. 55, Cape 60, Grnwch. 64, Brsls., Glsgw., Eome, A. G. Albany 465 Groombridge and others. Groombridge and others. Glasgow 90. only for proper niodon.) Brln. J. bh., Yrnl., Oxird. 60, Cape 60, 80, Glsgw., Can.hr., Pulk. 75. Rome, Grnwch. 80. Glsgw. 90. 473 Brad.5.... Pulk.55, Yrul.,Glsgw..Brln., EomcGrnwcb.SO 474 Brad.S9 Pulk. 5,1, 75, Yrnl., Grnwch. 00, 72, Leidn., Lpzg., A. G. Hlgfrs., Eome, Cambr. U.MTED STATES AND MEXICAN BOUNDARY. Authorities for star catalogue— Cimt'manA. 59 No. Authorities for proper motion. Authorities used for declination in computing latitudes on the boundary. Observations added on revision. 475 476 477 478 479 480 481 482 483 484 Glsgw. 90, Green- Greenwich 89, 90. Greenwich 89, 90. Grnch.90. Grnch. 90. Grnch.89,90. Grnch. 90. Vienna (Ottakriug). Grach.89,90. Washington 79, 85. Grnch. 90. Greenwich 89, 90, Glsgw. 90. Greenwich 90, Glsgw, 90. Cinn. Grnch. 90. Greenwich 89, 90. Grnch. 89, 90. Glsgw. 90. Grnch.89. Groombridge and others. Gmwch. 64, 87, Glsgw., Rome Brad. 13 Grnwcli. 60, 64, 72, 80, Talk. 55. 75, Brsls., Yrnl., Canibr Rome Pulli. 55, Gruwch. 64, Brsls , Glsgw Brad. 4 Tulli. 55, Trul.,Br8l8.,Gls<'w., Gmwch 80 Auwers's 303 Stars Groombridge and later. Piazi-.i, Groom- bridge, anr., Grnwch. 80 . . Yrnl Ednbro., Oxfrd. 65, Brsls., Amgh 75 Grnwch 80 Groombridge and later. Brad 5 Grnwch. 60, 72, 80, Pulk. 55, 75, Yrnl., A. G. Hlgfrs., Rome Pulk 55 75 Grnwch. 60, 64,72,80, Yml., Glsgw , Rome Brln. Jrbh., Yrnl., Oxfrd. 60, Glsgw., Cambr., Pulk. 75, Rome, Grnwch. 80,88. Pulk. 55, Yrnl., Ednbro., Rome, Brln., Gmwch. 80, Palmero (reduced from 6 Pr. Vrtcl. obsrvns.). Oxfrd. (rejected hut retained on revision), Brsls., Grnwch. 64, Pulk., 5.S, Yrnl., Glsgw. Pulk 55 Yml Grnwch. 64, Brsls Rome Glsgw., A. G. Albny Brad 3 Pulk.55, Yrnl., A.G. HI gfs., Grnwch. 72 Groombridge and later. Groombridge and later. A.G. Chrstana., Grnwcli. 80 UNITED STATES AND MEXICAN BOUNDARY. AnihoritUs for star catalogue — Coutiuueil. 61 Brad. 5.. Brad. 3.. Brad. 4. Pnlt. 55, GIsgw., Grnwch. 64, Gtngn., Rome, Krlsrh . Palk. 55, Amgh. 75, Grnwch. 64, Glsgw., Rome Palk. 55, 75. Gmwih. 60, 64, Tnil., Cambr., Krlsrh . . . Piazzi, G; bridge 568 Brad. 7.... Oxfrd. 60, lionii, Piilk. 5.^., Cruwch. 64, lllngn Krlsrl.e. Grnwch. 60, 72, 80, ( )xrrd. 60, Pulk. .=■,->, Brsl.s., R« .. Glsgw., Crdba., G. Hlgfra ireenwich 89, 90, Glasgow 90. Brad. 3 , Brad.4 Brad. 2 and later. Brad.7 Piazzi and later.. Groombridge and later. Brad.4 Brad.4 Brad. 2 and later Brad. 10 id. 2 ,nd Arglndr. Brad.3 Groombridgo anil others. Brad.5 Br.id.4 Groombridge and others. Groombridge and others. Piazzi and others Brad.4 Groombridge and others. Groombridge and others. Brad.8 Brad. 6 Groombridge and others. Brad.9 , Groombridge and others. Brad. 1 and others Brad. 10 , Brad. 11 Grnwch. 60, 64. 72, 80. Oxfrd. 60, 70, Pnlk. 55. Brussels. Trnl.. Rome, A. G. Helingfors. Pulk. 55, Trnl., Glsgw., Grnwch. 64, 72, 80, Rome Brln.Jrbh., Pulk. 55, 75, Cambr., Rome Pulk. 55, Grnwch. 64, 80, Glsgw.. Rome Brln. Jrbh., Yrnl., Cambr., Rome, Pulk. 75, Grnwch. 80 Yml., Pulk. 55, Oxfrd. 60, Brsls., Glsgw., Grnwch. 80 Glsgw., Rome, Pulk. 75, Grnwch. 80 Greenwich 89, 90. Pulk. 55, 75, Grnwch. 60, 80, Brsls., Trnl., Glsgw., A. G. Albiiy., Rome .. . Brln.Jrbh., Oxfrd. 60, Trnl., Brsls., Glsgw., Cambr., Pulk. 75, Grnwch. 80, Auwers'a303 Stars. Pulk. 55, 73, Oxfrd. 60, Brsls., Yrnl,, Grnwch. 72, SO. (Nos. 3744 aiul 3745 I the s Grnwch. 60, 72, Pulk. 55, Brsls, Tril., A. G.Hlgrs Pulk. 55, Glsgw., Grnwch. 64, Rome Brln. Jrbh.. Oxfrd. 60, Trnl , Glsgw., Cambr., Pulk. 75, Grnwch. 80, 88 . Pulk. S.'i, Grnwch. 64, 72, 80, Brsls., Rome Brln. Jrbh,. Yrul., Pulk. 55, 75, Cambr., Rome, (ireenwich 80 , Glsgv Green Glasg Pulk. 55, Grnwch. 60, 64, 72, 80, Oxfrd. 60, Brsls., Rome. Pnlk. 55, 75, Glsgw., Rome, Grnwch. 80 Brln.Jrbh.,Br8ls., Trnl,, Cambr., Rome, Pulk. 75, Grnwch. 80, 88, Glsgw. Brln. Jrbh., Oxfrd. 60, Glsgw., Brsls., Trnl., Cambr., Itome, Pulk. 75, Brsls., A. G. Chrstana., Grnwch. 72, 80, Rome Pulk. 55, Brsls., Grnwch. 72, 80, Rome Pulk. 55. Trnl., Brsls., Glsgw., Grnwch. 72. 80, Crdba., Krlsrhe. 85. . . Pulk. 55, Glsgw., Grnwch. 64, Trnl., A uwers' 303 Stars Pnlk. 55, Bonn, Brsls., Lpzg., Leidn., Glsgw., Grnwch. 72, 80, Rome . Pulk. 55, 75, 91 Pr. Vrtcl., Rome, A. G. Hlgfrs Pulk. 55, 75, Oxfrd. 60, Grnwch. 60, 64, 80, Brsls., Trnl,, A. G. Alban Brln. Jrbh., Trnl., Oxfrd., Glsgw.. Cambr,, Pulk. 75, Rome, (ireenwii 80,88. Brsls., Grnwch. 64, 72, A. G. Chrstana Pulk. 55, Grnwch, 60, 72, 80, Glsgw., Yrnl., Brsls,, Crdba., Krlsrhe, i rejected (1 obsrvn). Brln. Jrbh., Oxfrd. 60, Trnl., Glsgw., Cambr., Pulk. 7.^., Rome, A. Albny., Grnwch. 80, Auwers's 303 Stars. Pulk. 55, 75, AG. Hlgfrs Trnl., Pulk. 55, 75, A. G. Hlgfrs., Brln., Rome, Grnwch. 80 Brln. Jrbh., Pulk. 53, 75, Trnl., Cambr., Rome, Grnwch. 80 Brln. Jrbh., Pulk. 55. 75, Oxfrd. 60, Trnl., Glsgw., Rome, Grnwch. 80, 303 Stars. Greenwich 89, 90, Glsgw. 90. Karlsruhe 89. Glsgw. 90. Pulk. 62, Prime Ver Karlsruhe 88. Greenwich 89, 90, Glsgw. 90. Pnlk.62, Prune Ver- tical, Grnch. 89. Greenwich 90. Pulk.85,Greenwich 89, 90, Glasgow 90. 62 UNITED STATES AND MEXICAN BOUNDARY. Authoriiics for star catalogue — Continued. No. Authorities for Authorities used for declination in computing latitudes on the boundary. Observations added on revision. 602 603 604 605 606 607 608 609 610 611 612 613 6U 615 616 617 618 619 620 621 Pullt.55,75,GrnwS!>2, to February, 1893, consisted of triangulation near El Paso, Tex., twelve latitude and azimuth determinations between that point and Nogales, Ariz., small triangulations near San Pedro liiver and near Nogales, an azimuth and latitude determina- tion near Yuma, and another 20 miles below, and a triangulation counecting them. The following table shows, in condensed form, the time expended at each of the astronomical stations No. 1 to No. 12, El Paso to Nogales, and the observations se(!ured at each : station. From— To- Number ollati- tude ob- serva- tions. Number ofazi. mutli Remarks. No 1 1892. Feb. 12 Mar. 21 Apr. 8 Apr. 17 May 20 1892. Mar. 20 Apr. 7 Apr 16 67 39 iR 13 12 9 .Mso trian-uLatiou. Do. Also triangulation and tangent. No 3 May 19 130 June 8 99 No 5 No 7 June 30 1 July 31 99 No 9 Ang. 30 Sept. 29 Sept. 30 Oct. 31 Nov. 1 Nov. 17 101 106 126 No. 11 - No. 12 Nov. 18 Jan. 11 121 The dates recorded opposite each station include the time spent in moving to the next station. The latitude observations were all made with a zenith telescope. Each set for azimuth consisted of ten pointings each on star and mark with eye-piece micrometer. At each station the measurements of horizontal angles at the station necessary to connect the observed azimuth with the " tangents" ending and commencing there were made, and the magnetic declination was observed. It being considered desirable to have the results of the observations available as soon as pos- sible, the final computations for each station were made before leaving the station and between the dates recorded above. Each computation was verified by a second person before being accepted as final. In a few cases the latitude computation was not quite complete on leaving the station, but even in those cases it was so nearly complete that the result was known approximately and the reliability of the observations was well established. The original records were written in ink, and ink duplicates of them were made. On January 12, 1893, the astronomical party left Nogales, Ariz., by rail for Yuma, Ariz. Between that time and February 28 they occupied Stations No. 13 and No. 14 at Yuma and 20 miles below, and executed a triangulation connecting those stations with each other and with other important points. At Yuiiia 105 observations were taken for latitude and 9 sets for azimuth^ and at Station No. 14, 20 miles below, 25 observations foi- latitude and 9 sets for azimuth. During the early part of March the astronomical party were busy with computing and other miscellaneous duties. About the middle of the month the party disbanded and its individual members were assigned to other duties on the survey. Between the dates September IS and October 3, 1893, Station No. 15, near Emory Monument I, at the Pacific south of San Diego, was occupied by myself and two assistants. Ninety-six obser- vations were taken for latitude and 9 sets for azimuth. From October 4 to December 22 I was busy with one assistant in preparing for publication the data of the astronomical and other determinations made under my direction during the progress of the survey. 64 UNITED STATES AND MEXICAN BOUNDAKY. All the observations for latitude, for iiziiuiitli, for time, for niiigiietic declination, and a part of the observations for horizontal angles were made in person by myself. Mr. James Page made nearly all the original computatious. To his efficiency as an accurate computer is due largely the success of the adopted method of making all computations at the station of observation. Mr. H. B. Finley not only performed the ordinary duties of a recorder, but he was very efficient as an aid in computing and in the measurement of horizontal angles. Much of the work of verify- ing the original computations was done by myself and Mr. Finley working together. He observed most of the angles of the Nogales triangnlation and nearly all in the Yuma triangulation. Mr. J. S. Bilby, as expert workman, contributed largely to the comfort and success of the party. To all these gentlemen I feel greatly indebted for the zeal and cheerfulness shown by them on occasions when it was desirable to work during very long hours and under trying circumstances. All the azimuth observations were made with Fauth repeating theodolite No. 725. The horizontal circle, 25 cm. (10 inches) in diameter, is graduated in 5' spaces and is read by two opposite verniers to 5". It is furnished, on the horizontal motions, with axis clamps and tangent screws working against spiral springs. The telescope has a focal length of 41 cm. and an objective 45 mm. in diameter. The eyepiece used magnifies about thirty diameters, and is furnished with a micrometer with which the azimuth observations were made. The standard or yoke of the instrument is of aluminum. The horizontal circle is covered with a protecting plate, which served its purpose so well that during two years of continuous service in a very dusty country, a part of the time on tangent work, so little sand and dust found its way to the graduated surfaces and the centers or spindles of the instrument that it was never found neccessary to take it apart for cleaning, and the graduation was brushed oft' but once, a discoloration having then collected on a few lines only. There was always an apparent yielding of the clamps and other parts when the instrument was used as a repeater, which caused every measured angle to be ten to twenty seconds too large when all final pointings were made with the tangent screws actiiuj against their opposing spiral springs. The yielding seemed an elastic motion, not jerky, and so nearly constant for any series of observations that it was eliminated, within the errors of observation, by the practice of " closing the horizon." By "closing the horizon" is meant, in this connection, measuring both the re(iuired angle and its explement, or difference from 360°, always turning the upper motion over the measured angle in the direction in which the circle readings increase and making all final ])ointings with the tangent screws working ogaimt their opposing spiral springs. Such a procedure gives two values for the required angle — the directly measured value and the difference between the measured explement and 300°. The mean of these two is the true value of the angle independent of the constant yield- ing of clamps and allied parts. That this method of observing sensibly eliminated the remarkably large clamp error was shown by the instrument giving consistent results in successive measurements of the same angle by the satisfactory closing of triangles in which angles were measured with this instrument, and by the fact that in cases in which the same angle was measured with this instrument and with a direction theodolite the results agreed within the errors of observation. For azimuth observations the theodolite was usually mounted on a wooden pier in the large observatory tent. The pier was a hollow triangular column, built of 3-inch pine, put together with screws and banded at top and bottom with heavy hoop iron. The top of the pier was covered by a pine plank held in place by screws and having the instrument foot-plates screwed to its upper surface. This cap was removed during transportation from station to station. The pier was set like a fence post at each station, about 45 cm. of its length being below ground. The earth was tamped solidly around it and its hollow interior was also filled with earth to give it greater rigidity. It seemed to be as stable as a brick or stone cemented pier, and its use saved much time and trans- portation in a region where neither cement nor water could be obtained without hauling by wagon over considerable distances. UNITED STATES AND MEXICAN BOUNDARY. 65 The observatory tent lield both the uzimuth theodolite and the zenith telescope mounted on their respective wooden piers about 1.3 mm. apart due east and west from each otiier. The tloor space of the tent was 9 feet from north to soutli and 12 feet from east to west, and the shape of the tent was that of a "lean to" shed, with roof sloping downward toward the north. The sides and roof of the tent wt re securely supported throughout by a wooden framework. The floor was made so as to be portable, in six sections, and was so supported by sleepers that no pressure was transmitted to the ground except at the four corners of the tent, as far as possible from the piers. This tent served as an oflice as well as an observatory. The mark used for azimuth work was an ordinary bull's-eye lantern, showing through a hole 1 inch in diameter in the front of the small box, which served to protect it from the wind. This light was placed from 1 to 3 miles from the theodolite at each station. Tlie time was obtained with sutticient accuracy for the azimuth work by sextant observations of the sun's altitude. Two mean and two sidereal chronometers were carried. Each chronometer was kept in its own leather case, which was inclosed in a well padded box (two chronometers in a box), and this box was inclosed in turn in an outer box, having a false inner top and bottom backed by systems of spiral springs to deaden the jarring and shocks of transportation. The rates of the chronome- ters proved abundantly satisfactory for the purpose for which they were used. As all the azimuth observations were taken near elongation, errors in time afi'ect the computed azimuth to a very slight degree only. With the exception of one station, all the azimuth observations were taken with the eye-piece micrometer by the method described in Bulletin No. 21, December 12, 1 890, of the Coast and Geodetic Survey. On the first night after the i)ier and tent were ready a single pointing was made upon the star to be used, and the time and reading of the horizontal circle recorded. The instrament was then left standing covered to protect it from dust and sand, with the lower horizontal motion clamped and the upper one loose. During the next day the upper plate was set to such a reading comi)uted approximately from the observation of tbe night before as would place the telescope in the vertical plane of the star about thirty minutes before or after the elongation near which it was to be observed. The azimuth light was then placed in this plane at a distance of 1 to 3 miles, according to the topography along the line of sight. The position of the light as thus located was always found to be sufliciently accurate. All observations were taken near elongation, usually within one hour, and Polaris was used at each station. The azimuth light having been previously placed nearly in the vertical plane of the star, the observations consisted simply of the measurement with eye-piece micrometer of the small horizontal angle between star and mark, tlie chronometer time of each star pointing being noted. For each set of observations, the axis of the telescope being made as nearly horizontal as possible and the horizontal circles being clamped so that the line of collimation of the telescope was nearly in the vertical plane of the mark, the routine was as follows: Five pointings with eye-piece micrometer were made upon the mark, the telescope directed to the star, and striding level placed in position; three i)oiutings were then made upon the star and the time of each noted by the recorder, the level was read and reversed; two more pointings upon the star with noted times, level read again; axis of telescope reversed in the wyes; striding level placed in position; three more pointings upon the star with noted times, level read and reversed; two more pointings upon star with times, and Anally five pointings upon the mark. Three such sets required from thirty to fifty minutes. At Station No. 5 the azimuth mark was placed to the westward of the station and its azimuth determined by using the theodolite as a repeater. At Station No. 10, in addition to the observations upon Polaris, S TTrsjc Minoris and 51 Cephei were also observed. The graduation on the striding level is numbered from the middle toward each end. The eye piece micrometer was always used in the position in which increased readings of the microm- 66 UNITED STATES AND MEXICAN BOUNDARY. eter correspond to a movement of the line of sight toward the east when the vertical circle is to the east, and toward the west when the vertical circle is to the west. The computation of the horizontal angle between the mark and the mean position of the star during the set was made in the same way at every station, and is shown by the examples of com- putation given below. The computation of the mean azimuth of the star during the set was made by three different formuhi^ at different stations. For Stations No. 2 to No. 4, No. (J to No. D, No. 11, No. 13, and No. 14 the azimuth of the star was computed as follows: Let q) = the astronomical latitude of the station. S =the declination of the star. A = the azimuth of the star counted from the north. ^, =the azimuth of the star at elongation counted from the north. r„ =the hour angle of the star at elongation. t = the hour angle of the star at observation. r = t^—t, or, what is the same thing, the chronometer time of elongation minus the chro- nometer time of observation. Then the azimuth of the star counted from tlie north is at the time of any observation A=A,.— sin 4, cos A,, cosec '. 19.219 .189 .170 .146 ,124 18.400 .391 .387 ,399 .393 I.ollj;. 21' 31" W. of Wa.sliington. Means. Means. + 14,4 -12,7 W W 6,0 6.1 8.0 7.8 19. 1696 18,3940 17.790 .800 .820 .852 .871 18,470 .470 ,469 .475 .462 +12.1 —2.0 -15.8 = Suin. 5772.0 17.8266 1 18.4692 UNITED STATES AND MEXICAN BOUNDARY. 67 a of Polaris = l" 18"' 4^;< 5of Polaii8 = 88o 41' 33. 4 " log tan

; one turn of micrometer = 123.73" ; one division of level = 3.68" ; = 95° 14' 45. = log sin

late ; Feb. 16, star 317 observed 24 " late ; Feb. 18, star 319 observed 8' tar 319 observed 24- late: Feb. 15, star 322 observed 20' late; Feb. 16, star 322 observed 20- late; Feb. 18, star 322 observed 20' tar 324 observed 70- late; Feb. 15, .star 329 observed 45 ■ late ; Feb. 15, star 330 observed 8 • late; Feb. 16, .itar 329 observed 11" tar 329 observed 34 > late; Feb. 15, .star 339 observed 6- late: Feb. 15. star 340 observed 25- late; Feb. 16. star349ol)served 16' late. of micrometer = 02.225". iion of level = 1.28". observations on 19 pairs. of Station Xo. 1 =31^ 46' 59.40" ± 0.06", of Monument Xo. 1 = 31° 46' 59.40" + O.OC". of Station Xo. 1 was about 4 miles above El Ta.so. Tex., just e;.st of tbe Rio Grande, near tbe Atchison, Topeka and Santa Fe meters east and 0.0 meter north of Monument Xo. 1. erved four times were given weight 1, three times 0.8, :ind twice 0.0. 76 UNITED STATES AND MEXICAN BOUNDARY. station No. :1, near Monument Xo. IS. Microm- eter reading. 17. 9BU 30.959 9.731 28. 530 20. 505 22. 482 10. 531 13.352 13.012 21.850 16.341 ■ 19. 918 25.700 22*004 29.521 13.269 27. 352 15.5 14. 824 47.9 22. 387 53.2 25. 491 49.9 21.061 50.1 20. 931 17.0 30. 691 46.9 24. 930 21.0 16. 257 49.9 30. 228 13.5 17. 151 61.1 24. 630 50.0 18. 459 45.9 23. 770 46.9 13.530 15.9 33.052 15. « 20. 339 52.1 23.392 15.8 48.9 10. 120 19.3 62.8 24. 001 20.7 64.0 23. 400 47.0 13.6 18. 091 50.9 17.0 32.110 49.0 14.9 12.428 16.0 50.8 21.403 14.5 49.1 19.089 15.6 50.1 31. 070 17.0 53.8 28.732 48.2 14.9 26. 662 15.8 49.7 18.321 13.5 47.4 24. 049 14.1 48.2 25. 738 17.7 r.2.0 14. 540 48.0 13.9 25. 069 14.9 49.0 19.710 20.0 .50.3 15.879 19.2 .50.0 21. 119 17.0 48.0 21.819 49.1 17.0 10.859 13.9 46.6 16.178 55.0 21.9 25.920 14.9 49.0 10. 481 .50. 15.0 24. 252 13.0 49.1 17. 605 11.3 47.7 22. 537 7.7 43.8 17. 748 0.8 40.2 29. 6.51 53.6 16.0 8.100 55.0 17.0 22. 333 13.0 51.0 13.577 54.2 10.1 30. 300 56.4 18.8 23. 039 54.0 16.1 15.441 52.0 14.0 18.011 51.9 13.9 12. 137 11.1 49.2 28.164 46.1 19.9 60.27 60.44 59.57 61.26 60.46 59.96 Mar. 21, star 310 observed 29 ' late ; Mar. 21, star 314 observed 12 • late ; Mar. 21, Mar. 21, star 329 observed 54 -Lite; Mar. 21, star 343 observed 46' late; Mar. 21. 6 Mar. 21, star 393 observi-d 13 " late i Mar. 21. star 399 observed 13 • late ; Mar. 22, s One turn of micrometer = 62.103". One division of level = 1.28". Total, 39 observations on 39 pairs. Latitude of Station No. 2 = 31° 47' 00.21" ■ 0.07". Latitude of Monnment No. 15, = 31° 47' 00.34". Latitude Station No. 2 was 4.1 meters soirtll and 5.3 meters wist of Monument The mean place, 1892, for star No. 400 as used in Uie latitude computation was ■ 322 observed 16 • late ; Mar. 21, star 328 observed 1 371 observed 20 " late ; Mar. 21, star 392 observed 401 observed 4 " late. UNITED STATES AND MEXICAN BOUNDAKY. Station Xo. S, near Monument Xo. .'(!. 77 P 1341 ■ E.J. y , . Draconis J E. ,T. 41 ^l Leon.MinJi , E.J. a , I ITra. Miy.J Pfl37 Microm- Level. Slar No. N.oi- S. Mieioni. eter reading. Le N. rel. Latitude, 31° 46'. reiiin,. N. s. t. d. rf. '• d. .. 17.491 50.9 18.0 307 S. 22.681 13.5 46.2 57.76 :io. 632 55.1 22.1 309 s. 9.670 18.8 52.0 57.89 30. 510 19.9 53.7 313 Jf. 10. 842 53.2 19.2 58.59 )7.6,'i7 16.5 50.5 315 N. 22. 391 49.4 15.1 57.24 24.9«0 17.7 51.9 319 N. 15.465 51.1 16.9 58.21 8.817 1.-1. 2 50.0 324 N. 31.387 50.7 15.9 ,50. 78 28. IG 1 55.2 20.2 328 S. 11.844 19.8 55.0 57.71 19.399 51.2 15.9 330 s. 20. 128 14.0 50.0 58.98 22.069 .51.7 16.0 334 s. 18.498 15.0 51.0 57.82 16.246 49.2 13.0 340 s. 23. 242 11.5 48.0 58.65 9.612 53.4 16.9 345 s. 30.213 15.2 52.0 59.09 24. 189 50.1 13.1 349 s. 17.020 12.1 49.0 57.98 12.149 10.9 53.8 355 N. 27. 720 54.0 17.0 57.70 12.661 51.0 13.5 366 S. 25.720 12.9 50.1 57.96 21.919 52.9 15.0 371 s. 18.190 14.5 .52.0 57.70 16.010 .56.0 18.3 375 s. 24. 140 17.9 55.3 58.05 23.415 51.8 13.9 380 s. 17. 251 13.0 50.9 57.80 12.091 14.9 53.4 390 N. 28. 409 54.7 16.0 .57, 76 26.491 15.0 53.8 393 N. 13.857 54. 15.5 58.14 15.490 54.0 15.3 399 S. 26. 139 15.0 53.9 57.75 32. 139 14.0 53.0 401 N. 7.288 53.3 14.8 58.92 19.391 52.0 13.0 404 S. 21. 261 12.1 51.2 67.43 27.569 13.8 52.8 400 N. 13.318 52.9 13.8 67.47 11.092 9.8 48.8 409 N. 29.539 49.0 10.0 57.22 18.750 13.5 52.7 414 .V. 21. 980 52.9 13.5 57. 93 24. 851 12.1 51.4 417 N. 14.679 52.0 12.6 58.59 21.890 11.0 50.2 421 X. 17.992 50.9 11.2 58. 18 29. 010 66.1. 16.9 424 s. 11.518 15.6 55.1 57.92 14.911 15.2 5.5.0 I" 1350 N. 24. .501 54.9 15.0 .50.70 32.091) 55.1 15.6 J. A Ophin. S. 8. .'592 15.6 ,55.2 54.77 24. 192 18.0 51.5 303 N. 15. 501 48.0 14.6 58.27 15. 748 51.0 17.1 305 S. 25. 298 17.9 52.0 57.00 15. 501 52.0 17.0 311 S. 22.251 12.9 48.0 .58. 10 2u.G:a 12.9 48.0 I'963_ N. 10. .582 50.0 14,0 58.11 31.108 14.2 51.0 1-1004 N. 9.279 511. 14.0 58. 38 27. 742 ..-,.0 52. 1 , K. J. 2 ^ I Can. Ve.i. 1 N. 13. 512 52.3 15.2 .58. 03 18. 52(1 46.9 9.9 1 E-J-y , IVivgii. (m)/ s. 19. 908 9.2 58. 1(> 20, 359 52. 1 .::\ 28. 509 .53.0 10.8 20. 911 1...0 51.5 301 P(5293) J. 4 2 ^ Loon.Min. J E.J. cr» > Clancri. (in)/j Apr. 8, star 329 observed 16" late. Apr. 12, star 295 observed 11 " late ; Apr. 12. star 21 One turn of micrometer = 62.118". One division of level = 1.28". Total, 46 observations ou 46 pairs. Latitude of .Station No. 3 =31° 46' 58.00" ± 0.05". Latitude of Monumeut No. 26 = 31=> 46' 58.08". Latitiub^ Station No. 3 -svaa 2.5 meters south aud ,) The I1I0.-IU place, 1892, lor the star No. 400 as u3„d Monument No. 26. 78 UNITED STATES AND MEXICAN BOUNDARY. Sialion Xo. 4, intersection of parallel 31'^ 47' and iiiiridiaii, near Monn Microm- eter reading. Star N.orS. Microm. eter reading. Level. I/atitude No. N. s. 31°4o" I. d. d. 315 N. 22. 581 52.0 22.1 59.11 316 N. 22.442 47.2 13.0 58.23 31.5 X. 22. 490 50.0 17.0 57.90 313 N. 22.459 49.1 14.0 58.47 315 N. 22. 829 54.0 17.9 68.59 315 N. 22.470 50.2 17.0 58.74 315 N. 22.886 54.1 19.0 58.08 319 N. 15.258 45.8 15.0 50.63 310 N. 15.462 43.0 8.7 56.17 319 N. 15, 529 55.4 22.3 58.79 3in N. 15. 852 57.7 22.0 58.84 319 N. 15.408 53.1 16.5 59.14 319 N. 13.410 52.0 18.0 58.97 319 N. 15. -,'•.4 52.0 10.1 59.26 324 N. 31.814 50.1 19.0 59.09 324 N. 32. 340 51.2 17.0 58.64 324 N. 31. 270 51.8 18.2 58.64 324 N. 31.683 51.9 15.4 59.40 324 N. 31. 273 50.0 13.0 58.01 324 N. 31.350 50.9 10.3 58.50 324 N. 32.093 54.9 18.0 59.13 328 S. 11.911 13.0 44.8 57.31 328 S. 11.943 13.9 47.9 57.85 328 S. 11.703 12.9 50.0 58.07 328 S. 12. 018 14.4 52.3 58.80 328 s. 11.091) 10.3 51.0 58.37 328 s. 11.800 13.1 51.0 58.75 ■ 330 s. 20.086 8.9 40.0 59.74 330 s. 20.848 11.9 45.8 59.44 330 s. 21. 058 23.8 57.1 58.77 330 s. 20.505 10.0 47.2 59.24 330 s. 20. 018 12.9 50.8 58.69 33D s. 20.931 21.7 50.2 58.74 330 s. 21.019 10.4 54.1 58.41 334 s. 18.202 14.1 40.0 00.21 334 s. 18. 185 15.8 49.1 57.81 334 s. 18. 421 20.3 54.0 58.21 334 s. 18. 233 9.7 47.7 68.30 334 s. 18. 499 18.0 50.7 58.50 334 s. 18. 572 15.0 50.1 58.54 334 s. 18.010 15.0 53.3 58.32 340 s. 23.492 17.5 49.6 59.67 340 s. 23.511 17.0 50.3 58.49 340 s. 23.051 19.9 53.8 58.03 340 s. 23. 242 14.0 63.0 58.61 340 s. 23. 141 10.1 55.1 58.51 340 s. 23.700 14.0 49.9 58.71 340 s. 23.540 14.5 63.5 58.45 3J5 s. 30. 035 15.6 48.0 58.92 345 s. 30.381 12.8 40.4 58.81 345 s. 29.908 10.7 50.2 58.19 345 s. 30. 032 14.0 52.8 58.46 345 s. 30. 203 10.0 49.0 58.74 345 s 30. 298 14.0 49.9 58.62 345 ,s. 30. 539 12.8 51.9 58.64 349 s. 10.541 21.7 54.1 64.48 349 s. 16.385 17.9 62.0 58.48 349 s. 10.362 1.3.1 46.8 58.66 349 s. 10.509 16.0 55.0 57.79 349 s. 17. 059 14.1 53.3 58.31 349 s. 16. 520 15.0 51.0 58.65 349 s. 10. 439 14.1 53.4 58.00 1892. Apr. 18... 18.031 24.761 I 24.941 ; 25.070 23.285 24.919 i 24.883 : 23. 180 9.180 9.701 8.690 9.080 8.660 8.732 9.471 28. 259 28. 319 28. 107 28.301 28.071 28. 239 20. 040 20. 172 20.381 19. 936 19.970 20. 300 20.408 21.852 21.819 22. 029 21. 850 22.119 22. 222 21.681 16. 480 16. 572 10. 143 10.313 16. 227 10. 800 10.010 9. 030 10. 01(1 9. G59 9.090 9. 904 9.990 10. 179 23.735 23. 579 23. 820 24. 300 '23. 804 23. 058 19.6 12.3 25.0 20.0 52.7 44.0 47.5 57.5 50.3 60.9 57.7 55.7 '48.9 50.2 54.5 48.0 57.0 51.5 '• 55.4 50.1 51.2 52.8 47.0 46.8 51.0 53.3 SI 51.0 48.0 52.8 47.5 54.0 j 53.3 52.6 53.7 50.2 51.2 49.2 UNITED STATES AND MEXICAN BOUNDARY. fitatwn JVo. -i, hilersectioii of parallel Sl^ 47' and mendiaii, near Monument \o. */— Continued. 1892. Apr. 18 Microm Level. Star No. N-r X.orS reding reading s. N. 1 s- -310 46'.*' (. d. d. j ,. d. d. " 12.735 14. S 47.3 1 355 1 N. 28.331 47.1 14. 6 i 58. 62 12. 641 16.0 50.4 355 1 ^• 28. 280 51.4 16.9 58.38 12. 150 17.9 51.3 355 N. 27. 795 52.0 18.4 58.14 12. 100 55.1 1 355 1 ^■ 27.833 56.3 17.1 58.72 12.169 ! 15.5 54.9 I 335 N. 27. 810 54.7 15.5 58.24 12.429 1 14.0 50.1 355 N. 28.060 50.3 13,9 59. 05 12.082 15.0 54.3 355 N. 27.719 53.3 13.9 58. 36 18. 032 50.8 18,0 ! 362 S. 21. 980 17.7 .50. 8 17. 880 ! 47.7 12,9 362 S. 21.821 12.0 47.0 59.35 18.000 51.5 17.9 362 s. 21, 939 17.0 50.8 59.43 17. 839 511. r 11.0 362 s. 21.732 1 9.5 49.0 58.05 18.140 54.0 14.7 302 •S. 22. 069 14.0 59.27 18. 240 j 52.3 i 15.3 362 s. 22. 174 15,0 52.2 59.57 18.030 54.0 14.5 362 s. 21. 952 14.3 54.4 59.19 12. 850 51.1 18.1 366 s. 25.890 17.8 50.9 58.38 13.259 52.1 17.0 366 s. 26. 267 15.7 50.6 58.36 12.080 52.8 18.8 366 s. 26, 106 16.9 50.9 59.38 13. 289 ■ 54.7 j 14.9 366 s. 25.295 12.9 52.8 58.93 13. 262 53.8 1 13.9 366 s. 26. 292 13.5 53.2 58.91 13.334 54.0 16.9 366 s. 26, 348 16.5 54.0 j 58.50 13.354 50.0 19,0 366 s. 26. 365 18,9 49.9 58.55 21. 672 , 53.2 18,8 371 s. 17. 927 17.9 51.0 58.88 21.509 50.1 15.0 1 371 s. 17.751 14.0 49.0 58. 70 21.558 53.8 19.2 371 s. 17,788 18.0 52.4 58.64 21.923 50.0 16.0 371 s. 18. 139 13.5 53.5 59.13 21.192 55.1 15.2 371 s. 17.419 14.5 .54.1 58.57 21.507 55.0 17.9 371 s. 17. 789 17.9 55.0 58.21 22.010 43.4 12.1 371 s. 18.231 12.0 43.1 58.30 15.760 47.1 14.0 375 s. 23.839 13.5 46.8 58.27 15.842 50.2 15.2 375 8. 23.910 14.7 49.8 58.29 15.830 53.2 19.0 375 s. 23. 889 16.9 51.0 59.31 16.050 .12.1 12.1 375 s. 24.110 13.0 53.1 57.54 15. 693 54.9 14.9 975 s. 23.728 14.0 54.0 58.19 15.870 53.3 16.0 375 s. 23.929 17.0 54,1 58.21 15. 909 52.0 20.7 375 s. 23.940 20.9 52.2 58.02 23.545 46.0 12.8 380 s. 17.363 12.2 45.8 58.93 23. 609 49.0 14.0 380 s. 17.382 12.1 47.0 ,58.47 23.245 .52.2 17.9 380 s. 17.050 19.0 53.2 57.94 22. 751 53.3 ,3.1 380 s. 16.550 12.8 53,0 58. 79 23.091 .53. 13.0 380 s. 16. 849 11.9 52.0 58.21 22. 960 .55.5 18.2 380 .s. 16. 720 17.9 35.2 .58.23 23. 216 47.0 15.0 380 s. 16. 978 15.1 46.9 58.52 15. 050 47.3 13,9 386 s. 25. 750 12,3 46.0 58,30 14.819 51.2 15 5 386 s.. 25.505 13.9 49.8 58.24 14. 700 48.8 U.3 386 s. 25.429 16.5 49.9 58.07 14.449 54.0 13.2 386 s. 25. 160 13.0 54.0 58.51 14.685 54.0 13.5 386 s. 25.351 52.0 58.40 14. 770 .55.0 17.6 386 s. 25.450 17.0 54.8 58.43 14. 641 50.2 19.0 386 s. 25. 345 18.2 49.0 59.59 11.669 16.0 49.9 390 N. 28.019 50,3- 16.8 58.48 12.2.50 12.0 47.9 390 N. 28. 630 49.1 ! 1.3.1 58.20 , 11.991 10. 9 51.5 390 N. 28.332 51). 2 15.5 58.6 12.039 ) 13.0 54.0 390 N. 28.391 53.7 12.8 58.64 12. 220 1.5.5 56.0 390 N. 28.639 57, 2 [ 16.8 57.75 12. 193 18.9 .56.4 390 N. 28. 602 57 6 20.0 58.47 12.229 16.0 47.1 390 N. 28. 600 46.9 15.0 58.96 13.3 47.2 393 N. 13.435 48.9 15.0 58.14 26. 040 20.0 55. 393 , N. 13. 439 54.8 20.0 59.26 26. 261 12.4 53.3 393 N. 13. 700 53.5 12.0 58.42 20.421 15.0 55.8 393 N. 13.890 57.1 10.3 58.42 20,241 15.9 53.3 393 N. 13. 700 53.4 16.0 58.42 20.560 17.5 48.8 393 N. 14.000 47.6 10.7 58,55 9 observ a 21' la <■.: Apr. 20, 8t,ar a 23 obsei ve N S241 1 J. > N. E.J. a CeplK 20. 963 20. 645 10. 319 13.5 53.3 3D. 8211 13.8 56.1 31. 338 l.'i. 54.9 10.834 15.0 57.5 11.176 13.2 55.0 29.827 .50.2 13.9 20.959 14.9 54.8 14. 190 13.4 58.2 14. 943 13.3 53. C 21.948 13.0 55.9 22.318 14.8 5.5.0 9.230 12.0 55.0 8.819 14.8 55.0 22.821 55.9 12.9 26.340 29.361 29.511 11.679 23.099 I 23.011 : 21.437 I 25.580 ;.9n9 17.945 17.281 I 29.070 28.979 9.030 1.490 18.763 25. 175 25. 880 16. 063 18.379 31.799 31.379 16.585 53.0 58.5 14.0 16.0 11.0 53.3 13.0 53.6 57.0 52.0 57.0 13.5 15.2 13.8 ■ 55.8 13.5 14.0 53.8 55.3 57.52 57.77 58.11 57.41 57.12 58.48 58.16 58.17 58.41 57.93 57.91 58.04 58.45 58.11 57. I9 57.15 57.95 57.89 56.95 57.56 58. U3 57.90 57.37 .57.74 57.73 57.81 58.08 1, r. . \( Herculisi |l Herculisi 16.8 ' 50.2 / •'^■G™o"> I I 2343 /I 17.8 ' 51.9 P. 1513 58.70 57.29 ,1 *■" ! One turn of micrometer ^= 62.101". One division of level = 1.28". Total, 102 observations on 57 pairs. Latitnde of Station No. = 31° 19' 57.94" Tbere was no monument near the station Weight of pairs on which two observatio 84 TTNITED STATKS AND MEXICAN BOrNDARY. yo. 7, S miles west of San Lids . Muiiiniieiit No. 67 Star So. V Microni' 11.571 452 », J52 s. 18.842 391 N. 9.060 395 S. 24.668 398 N. 8.154 402 S. U. 451 402 S. 13. 021 408 N. 28.368 412 S. 22.600 412 s. 20.549 416 s. 29.240 410 s. 27.728 420 s. 30. 248 420 s. 29.510 425 s. 24.649 425 s. 23.670 427 N. 26.696 427 N. 25. 589 420 s. 10. 941 431 N. 21. 791 431 N. 19. 991 433 X. 19. 610 433 N. 18.827 436 N. 29.591 430 N. 28.340 438 S. 14. 500 438 s. 13.080 440 s. 29. 780 440 s. 27.908 i 442 N. 24.472 442 N. 22.062 444 N. 29. 108 444 N. 27.998 446 N. 13.071 440 N. 11.955 448 X. 31. 106 443 N. 29.686 450 N. 14.381 450 N. 13.382 456 N. 19. 573 i 489 14. 789 489 s. 14.559 t 494 s. 21.791 494 s. 21.491 P. 1776 s. 8. .348 E. Grooin^ . ... 57.6 498 53.8 P. 1783 / B- 1 {^Aanarul I 1 Pegasi 1 , E..I. , ..4 U ^ 1 1 Ceiilici / n,li. '! N- ! P. 1513 N. P. 1513 N. 455 N. 455 N. 400 N. 4M ■■^- N.or Microm. eter reaxling. Level. Latitude, X. s. 31° 19'. N. 29.479 d. 54.1 16.9 " 56.68 N. 29. 781 52.2 20.0 56.35 S. 31.252 11.4 41.1 55.82 N. 16.992 50.1 20.0 56.94 S. 32.168 19.3 60.1 55. 6« N. 27.403 56.1 24.0 56.17 N. 25.940 49.8 17.9 57.25 S. 14.279 20.0 52.3 55.99 N. 19. 562 49.3 17.0 57.36 K. 17.646 52.7 20.9 56.80 K. 13.409 51.7 19.0 56.97 N. 11.968 61.8 17.0 50.64 N. 11.980 47.0 14.7 .57.49 K. 11.389 51.6 18.9 57.34 N. 18. 203 53.7 20.8 57.66 X. 17.261 51.1 15.3 57.01 S. 15.114 18.9 51.7 57.08 S. 13.939 17.9 53.9 56.54 X. 32. 810 52.0 19.3 56.14 s. 20.848 18.5 50.8 .56.85 s. 19. 029 17.9 51.0 57.21 s. 23. 940 20.8 .53.0 56.33 s. 23. 131 15.3 49.8 57.06 s. 12. 089 18.9 .51.0 66.84 s. 10. 851 17.0 .52.2 56.86 X. 27. 456 52.0 19.8 56.41 N. 26. 128 54.0 20.1 57.39 X. 12.761 53.3 21.2 57.96 X. 10.991 54.3 14.2 56.20 s. 19. 679 20.2 52.3 56.26 s. 17. 769 14.0 54.0 56.61 s. 12. 889 18.4 50.4 56.98 s. 11. 670 12.0 52.3 50.95 .s. 29.314 18.0 49.9 57. .57 s. 28.173 18.3 54.2 57.28 .s. 12. 159 24.3 56.2 56.34 s. 10.648 13.9 49.8 .56. 61 s. 27. 349 19.3 51.7 56.23 s. 26.270 13.5 53.2 56.96 s. 22.499 19.2 51.7 .56.74 X. 26.010 52.3 18.9 56.82 X. 25.902 56.1 11.3 57.13 ! X. 18. 150 53.1 18.2 .57. 17 X. 17.991 57.0 11.5 .57.27 X. ! 31.230 56.3 20.8 .56.46 s. 16. 682 14.9 .■52.3 56.49 2.5.911 51.2 20. 599 50.9 15.410 5.5. 8 12. 888 .i4. 2 27.820 52.0 26.791 50.0 19. 992 53.7 22.700 14.9 .55. 46 .57. 15 July 27, star 402, obsci ITNITEI) STATES AND MEXICAN BOUNDARY, T. 3 miles ivrst uf San Li(h Sj)iinfj, near Monument jV'o. o; Level. I [ „ I Mirrnn, 1892. July 26 . ■iSerpenlis' E.J. > iSerpentis' reading. 27. 14U 54.4 26. 368 53.3 13.800 10.2 13. 959 14.2 24. 072 53.2 24. 369 56.1 15. 678 57.0 .■1.808 55.0 22.508 14.9 10. 599 15.0 11.001 15.0 7.852 57.0 7. 728 .18.3 Star No. reading. 7.9 55.0 5.0 50.2 5.6 53.2 Level. ! Latitude, : I c I 30° 19'. 1 19.9 54.0, U. 121 ' 50. 1 24. 21. 520 19.1 54.2 57.60 15.402 17.2 52.2 57.41 13. 989 16.9 .54.2 .56. 73 13. 820 15.9 .56.7 .56.80 20.842 54.2 10.7 .--,6.29 27.009 55.0 14.0 55.91 16.918 15.2 53.0 56.51 17.223 15.0 56.0 56.74 26.612 54.0 16.1 56.49 26.921 55.9 14.9 56.87 22.i)75 55.8 17.9 56.88 22.741 57.5 16.2 56.85 28. 996 55.8 18.0 56.06 29.469 56.9 15.6 56.44 9.863 53.4 15.9 56.62 9.891 56.3 15.0 57.08 27. 689 15.5 53.2 56.55 28.280 U.2 56.2 50.54 11.935 54.5 16.7 56.93 11.979 58.0 15.7 57.28 25. 740 26. 318 27.522 ; 15. 753 311. 338 55.0 56. 62 59.4 56.64 54. 1 56.31 16. n 56.86 16.8 56.25 10.0 56.85 55. U 56.89 .59.2 56.84 10.8 rairs. Latitude of Station No. 7—31^ 19' 56.73' ± O.O Latitude of Alonuiucnt No. 67 =31'^ 19' 50.80" Latitude of Station No. 7 was 4.1 meters son; Weight for pairs on which two observations H6 UNITED STATES AND MEXICAN BOUNDARY. Slation No. S, San liernardino lianch, Arizona. Microm- roading. s. 22. 820 19.0 54 9 N. 24. 712 52.9 17.9 N. 30. 290 52. 5 1 17.6 .S. 19.327 18.1 53.4 s. 15.059 19.0 54.0 s. 19.510 17.2 62.8 s. 28.183 16.9 52.4 s. 29. 358 12.9 57.6 N. 27. 160 54.0 18.1 X. 21. 870 54.8 18.3 X. 16.611 .54.0 17.1 N. 21 221 53.0 15.8 if. 29.039 53.9 10.5 S. 15.032 ■14.9 52.3 s. 21.630 15.7 53.3 N. 30. 139 52.8 14.9 X. 20.491 61.1 20.0 N. 19.966 .50.1 17.1 N. 18. 152 52.5 20.9 X. 18.052 .53.1 19.1 N. 29.098 52.2 19.6 N. 29.690 53.3 18.3 S. 13.676 16.3 .50.0 s. 14.010 17.0 53.1 s. 28.901 24.0 68.0 s. 28. 881 18.5 55.0 N. 23.280 52.6 18.1 K. 23. 058 53.0 16.2 N, 28.621 53.9 19.0 N. 28. 790 52.1 15.0 N. 12.950 52.8 17.9 N. 12 864 54.2 17.0 N. .30.236 51.9 16.9 N. 30.308 53.0 15.4 X. 13.570 54.9 19.0 N. 13. 709 53.0 15.0 S. 11.097 16.3 53.3 X. 19. 049 54.0 16.2 N. 18.900 56.3 12.0 N. 28.002 65.4 17.5 N. 28.680 57.9 13.2 N. 17. 180 54.1 15.6 N. 17. 033 53.0 13.9 N. 19.219 54.2 15.3 S. 32.609 20.7 54.3 N. 23.470 51.9 17.8 N. 26.755 51.7 17.3 S. 14.079 1 18.6 52.8 16.5 52.0 53. 8 18.3 16.8 62,0 14.7 58.7 53.0 17.1 Microiii- reading. f- 10.259 57.6 13.8 59.62 ^. 16. 989 56.0 20.9 58.99 13. 68'J !7.9 52 8 58.72 9. 130 16.4 51.7 58.78 ^. 19.915 54.2 19.0 59.08 f. 26.829 ,56.2 21.0 59.65 ^. 18.782 53.3 17.8 58.97 10. 004 52.8 16.9 68.76 11.230 58.0 13.0 68.93 <. 11.599 17.9 53.9 58.70 ^. 17.859 17.4 54.1 58.32 ^, 21.940 17.1 54.0 69.38 s. 17.420 15.4 52.8 59.44 5, 9.800 16.0 53.4 59.03 v. 22.980 52.9 15.0 59.48 S'. 16. 990 54,0 16.1 59.36 s. 8.291 14.0 52.0 59,28 s. 19.501 19.1 50.7 58.92 s. 18.982 18.0 51.3 58.07 s. 22.391 19.0 51.6 59,19 s. 22.330 18.7 53,2 59.68 s. 11.479 17.7 50.9 59.03 s. 12.092 18.0 53.4 58.82 N. 26.758 .52.7 19.0 69.32 N. 27. 070 54.0 17.9 58.96 N. 11.961 55.9 21.7 59.71 X. 11.992 55 18.3 59.60 s. 18. 368 17.9 52.2 58.55 s. 18. 121 15.4 52.2 58.21 s. 12. 304 17.9 52.6 59.79 s. 12.480 14.2 51.3 59.86 s. 29.011 16.9 51.9 59.10 s. 28.928 16.0 53.5 59. 26 s. 11.080 16.0 51.4 57. 9G s. 11.160 13.8 51.4 58.91 s. 26. 440 17.0 53.2 59.23 s. 26.57K 13.2 51.7 59.23 X. 29.200 5.5.1 17.9 58.59 s. 21.77P 14.8 52.7 58.87 s. 21. 638 12.0 56.3 58.97 s. 10.796 15.0 53.3 58.78 s. 11.450 13.5 58.0 58.68 s. 23.049 14.0 52.8 58.84 s. 22. 962 15.5 55.0 58.79 s. 21. 579 13.8 53.0 59.05 N. 8.818 52.0 ' 18.0 58.89 s. 15.981 19.0 53.3 58.66 s. 13. 530 16.7 52.9 58.50 X. 27. 190 52.7 18.3 68.78 X. 22. 959 52.0 17.2 59.19 N. 13.561 52.2 17.3 58.89 X. 13.796 ' 58.1 16.0 1 58.80 N. 22. 159 52.3 1 17.2 58.08 X. 22.432 56.1 12.9 58 90 s. 29. 964 19. e 54.2 59.08 X. 27. 034 ] 51.9 16.6 5e.98 s. 12.362 18.9 54.1 58.69 X. 12. 342 1 63.0 17.8 59.71 X. 12. 575 j 68.9 14.9 58.79 s. 11.570 18.0 54.0 58.26 ■ 599 iibserved 15- lati; ■ 460 observed 32" late ; Aug. 16, star 451 observed 7" lato. UNITED STATES AND MEXICAN BOUNDARY. Station Xo. S, San Brrnardino Ranch, Arizona— ConVmaii 87 reading. 24.570 14.445 2U.425 10. !>90 14. 732 14. 820 28. 120 10. 925 11.518 18.240 32. 350 32.182 15.0 54.0 ! 56.3 53.1 1 15.7 19.9GC 17.0 15.611 56.7 15. 740 57.3 14. 228 56.2 14.058 58.0 22. 921 15.0 22.761 12.5 10.056 54.2 18.080 55.5 12.2 10. 53.0 . 56.6 I 53.1 I 53.3 [ S.5.5 Aug. 16, star 592 observed 8- late. One turn of micrometer = 62.099 ". One division of level = 1.28 ". Total, 100 observations on 75 pairs. Latitude of Station No. 8 = 31° 19' 59.01 " ±4.03". Latitude of Monument No. 77 = 31° 19' 58.99". Latitude of Station Xo. 8 -n-as 0.7 meter north and 23.8 mi Weight for pairs on which two observations were made, Microm- , eter reading. 15.845 54.6 18.9 59.98 26. 651 54.1 18.1 59. 02 21. 240 31.1 15.0 58. 62 24.502 ,52. 7 16.0 58.68 25. 009 16.4 53.1 58.94 25. 650 11.0 55.5 58.87 n.53U 52.0 14.8 58. 91 2S. 753 17.0 54.2 1 58.84 29.338 12.0 56.2 59. 07 21.461 16.0 53.2 59.10 9.400 52.8 15.3 68.82 9.249 56.3 11.8 58.62 j 25.461 53.0 15.9 58.77 27. 393 55.0 16.5 59.08 20. 952 57.5 19.0 59.77 26. 190 19.9 59.5 58.73 26.254 12.1 57.0 58.98 27. 819 15.0 55.8 58.49 27. 650 13.2 58.2 58.53 18. 070 .55.0 14.9 59.07 17. 905 57.1 12.9 59.68 25. 925 14.9 55.1 58.99 23.008 15.0 56.0 59.58 23. 164 11.8 56.2 59.43 26. 208 55.2 14.0 58.39 18. 960 55.4 14.0 59.35 26. 790 15.0 56.3 59.37 i 29.051 55.0 13.1 58.49 20 850 14.7 50.1 59.01 18. 250 14.0 56.2 59. 17 23.259 ' 14.5 57.0 59.12 14. 040 50.5 13.4 59.11 15. 810 12.1 56.0 59.81 28.333 12.4 56.6 59.23 11. 188 1 57.2 13.0 59.23 13.662 11.9 56.3 ' 59.24 1 27.858 58.0 13.6 58.64 ! 9.522 59.0 1 14.9 59.62 88 UNITED STATES AND MEXICAN BOUNDARY. Station Xo. 9, wenieni part of Sulpktir Spring Valley. icioiii- Le ■el. arting. N. S. t. d. 18. 590 50.1 14.6 18.580 .52.0 16.8 25. 209 15.4 51.7 1 21.985 19.9 55.3 27.729 14.8 51.0 27.210 17.3 53.0 18.401 16.8 53.1 ■ 18.491 17.4 52.6 11.161 51.7 14.9 10.739 54.0 18.9 14. 181 1G.9 54.0 13.606 17.0 52 3 27.431 52.3 15.0 28.449 10.3 53.7 27.851 17.9 53.2 27.874 53.3 16.0 27.820 54.0 18.5 24.281 18.5 55.1 13.701 18.4 54.4 14.090 1,5.5 54.0 19. 579 18.5 53.9 15.889 17.0 52.0 14.262 52. 17.0 14. 754 51. 9 18.8 52.2 52.8 K. 10.530 53.7 18.3 N. 10.051 53.2 16.3 N. 18.239 52.7 ! 17.2 N. 18.167 53.5 13.9 S. 32.041 16.9 52.6 s. 31.742 16.3 ; 56.2 s. 14.529 17.2 53.2 17.0 50.2 52.9 19.2 18.8 52.7 17.7 51.7 54.7 20.8 17. 940 17.8 52.3 10. 501 18.8 53.8 11.50!) 15.9 50.9 J9. 729 18.9 54.0 29. .'-.10 17.0 53. 9 23.079 10.9 .53.1 25. 071 52.8 17.2 25. 340 54.0 16.5 30. 791 53.2 18.0 19.319 18.1 53.8 19.512 19.0 54.9 14.472 18.2 53.9 14. 641 18.9 54.2 19.760 17.8 53.2 20.285 16.1 51.9 27.928 52.9 17.0 21.737 16.3 13.961 50.9 13.800 , 55.3 12. 875 50.3 12. 400 51.9 22.319 52.2 29.208 ' 26.771 26.241 11.334 17.9 53.3 5.73 15. 528 54.7 18.1 6.28 25.813 52.8 17.0 6.40 26.320 55.5 17.0 5.85 20.310 52.9 17.4 6.73 23.752 50.8 15.8 5.64 25.202 18.0 53.2 6.60 25. 598 18.0 54. 2 6.17 11.082 50.1 14.9 6.02 11. 390 53.2 16.7 6.19 28.411 18.9 54.0 6.24 28.450 15.2 52.2 5.97 21.498 17.9 53.2 6.05 21.340 12.0 52.2 .5.81 9.062 52.7 16.8 6.05 8.810 57.6 17.8 6.62 24. 591 53.9 17.8 6.26 28. 721 52.2 18.9 .5.72 28. 979 51.0 17.6 5.70 10. 150 18.1 . ,52.0 5.69 26. 070 53.7 19.7 6.13 26. 120 18.1 52.7 6.90 16. 090 18.8 53.2 5.47 14.270 14.9 49.0 5.86 26.651 55.4 20.7 6.05 22. 372 54.9 19.9 6.87 29.901 52.2 17.2 5.99 29. 202 49.0 13.9 5.46 9.670 .52.0 10.8 6.51 0. 542 55. 17.9 6.34 17.250 52. 7 17.1 6.53 14. 040 18.0 53.2 5.67 14.260 15.0 52.8 5.90 9.651 18.0 53.3 5.56 19. 891 53.2 17.9 6.41 20. 139 55.0 19.3 5.77 20.260 54.2 19.0 5.87 26.470 54.5 19.0 5.14 19.021 53.4 17.0 0.20 19. 582 51.9 16.1 5.08 12.3.50 17.0 53.0 5.94 18. 272 17.8 53.8 .1.50 UNITED STATES AND MEXICAN BOUNDARY. Station No. 9, western part of ^Sulphur Spring Valley — Continued. Microm- reading. 1892. Sept. 10. 16.8*7 53.2 17.1 17.081 57.6 18.4 18.625 49.0 17.8 18.280 54.0 16.9 17.610 51.4 18.0 19.738 16.3 49.6 10.269 19.9 53.0 20.070 52.7 19.1 11. 581 19.6 53.0 18.385 51.0 17.2 18.405 52.6 18.0 21.832 52.1 18.0 23.600 53.6 18.2 12.820 17.7 33.6 24.570 54.0 17.1 11. 590 53.2 1.1.9 11.492 53.9 18,2 28.950 15.2 53.2 27. 600 54.2 16.0 28.374 17.0 55.6 28.741 18.0 53.3 13.011 55.3 16.9 12.870 53.4 17.8 21.520 55.5 15.9 22.629 15.0 54.9 30.310 54.9 15.0 12.749 51.3 17.0 27.620 54.9 10.9 16.040 52.1 13.0 15. 305 50.3 18.9 13.110 51.6 19.7 21. 701 18.0 50.9 30.075 18.9 52.0 21.075 17.5 51.2 21.315 17.0 51.2 31.719 18.1 52.8 12.419 16.9 53.9 15,851 15.0 52.3 18, 385 17.0 54.2 20. 580 29.905 19. 187 28.779 20. 130 20. 140 17.515 16.390 27.108 23. 870 22. 191 .20 I :: i One turn of micrometer^62.16'l". One division of level^l.28". Total, 101 observations on 72 pairs. Latitude of Station No. 9 = 31o 20' 06.07" 4- There waa no monament near the station. "Weight for pairs on which two observations i S. Doc. 247- -10 90 UNITED STATES AND MEXICAN BOUNDARY. ■ San Pedro Hirer, 1 mile southeast of Monument No. 98. Microm- eter reading. Le 'el. N. S. (. d. d. 17. 310 15.0 52.7 10.495 15.9 54.7 13.530 17.0 56.0 12.809 18.0 52.7 22. 962 13.0 52.3 21.826 19.0 53.0 25.808 55.6 10.1 25.302 51.7 16.9 31.369 53.4 14.0 18. 860 14.7 54.5 14.051 14.1 54.1 19. 670 15.0 54.8 18.970 19.3 54.1 27.885 13.2 53.3 28.052 14.6 53.4 28.653 55.0 14.9 22.951 45.8 16.2 22.696 52.9 17.9 17.480 50.5 20.2 21.990 51.4 20.7 30.182 51.0 20.0 15. 200 18.9 50.1 21.770 18.5 50.1 31.371 50.6 18.9 27.051 53.5 18.0 13.305 18.5 54.2 24. 260 54.1 18.3 24.560 17.8 53.4 24. 099 18.0 51.9 26.481 19.9 55.4 26.093 16.5 49.3 17. 218 16.7 52.2 17. 800 16.1 54.6 11.360 54.1 18.1 11. HI 52.2 18.1 28.836 15.6 51.5 29.580 15.6 53.4 28.130 53.3 17.1 27.675 17.9 54,0 27.018 16.0 53.8 28.161 53.4 17.0 23.680 16.1 52.8 22.731 17.0 51.9 13.730 18.1 55.0 13.861 15.8 54.3 19.324 17.0 53.6 18. 080 17.9 52.7 15.650 16.3 53.0 15. 250 55.6 18.9 14.820 55.2 15.6 27. 588 17.0 54.0 20.579 19.9 50.4 11.771 54.2 17.0 10.801 48.9 17.9 18. 840 54.2 17.1 31. 090 14.0 51.2 30. 673 16.0 47.7 14. 399 16.0 53.4 25.182 53.2 19.6 21.960 54.2 17.1 14.100 53.0 15.2 13. 622 50.9 19.8 31.938 17.0 55.0 Microm- eter reading. 22. 828 29. 289 27. 270 26.730 18. 245 17. 228 13. 628 13. 098 9.060 20. 575 26. 932 20. 049 19. 390 10. 825 10. 990 11.900 17. 788 17. 492 21.640 8.320 12.750 27. 500 15. 931 14. 480 14. 040 12. 799 12.431 22.310 22. 900 28. 701 28.433 i 9.070 j 10.720 11.118 12.349 11.628 I 10.518 j 16.141 15.251 27.090 27. 209 21. 270 20. 955 24.710 25. 004 24.550 i2.no 11. 188 28.519 27.450 20. 900 9.238 8.901 25.670 9.161 54.5 55.4 55.0 51.3 50.9 56.0 17.0 54.9 52.8 57.2 50.9 53.8 56.4 51.9 15.0 55.4 54.1 54.9 54.2 53.0 51.2 51.9 53.2 50.9 18.1 16.2 17.9 50.4 48.8 53.3 17.0 16.8 16.0 19.8 .56.1 15.6 16.1 20.1 13.0 21.4 53.7 14.6 14.0 14.8 13.6 55.6 45.9 53.9 20.2 52.8 14.0 51.4 19.0 19.0 18.1 15.4 16.5 55.2 47.2 55.0 13.2 17.0 16.0 51.3 54.0 35.51 35.14 34.85 35.01 35.13 34.21 34.74 34.97 34.60 34.91 34.40 34.22 34.30 34.95 35.49 34.70 35.24 35.16 35.35 35.29 34.87 34.29 34.49 34. 73 34.85 33.98 34.12 33.08 34.18 35.70 31.04 33.61 35.13 35.22 34.38 34.92 35.31 34.93 34.54 34.79 34.44 34.21 34.05 33.52 34.63 34.41 34.32 34.45 35.37 35-48 34.94 34.27 34.94 34.44 ■ 615 observed 16" late ; Oct . 12, star 598 observed 12- late, UNITED STATES AND MEXICAN BOUNDAKY. 91 Slation Xo. 10, mar San I'edro Rive ill- simlheast of Monument No. 1892. Oct. 13. 14. Microra- reading. 12.618 25.719 25.209 12. 175 12.374 28.298 27.901 27. 501 13.281 12.575 10.568 18.797 31. 980 19.888 19. 250 9.740 22. 859 22. 070 21. 140 15. 129 18. 015 29. 810 16. 530 21.619 9.261 16.780 19. 930 11. 930 22.491 15. 461 21.092 29. 400 18. 120 Microm- reading. 15.415 14.0 16.948 13.0 16.270 18.1 27.258 56.7 14. 582 13.7 14. 050 16.0 26. 991 17.1 27. 178 17.8 10.961 52.8 10. 021 52.0 11.700 18.5 25.400 15.0 24.692 18.0 28. 851 51.9 19.320 19.3 19.416 18.6 6.923 16.9 21.731 17.8 21.281 15.0 30. 378 54.2 15.581 53.8 18.060 17.5 17.111 18.3 22.125 17.7 21.711 16.2 27. 418 51.2 22.230 50.8 13.480 52.6 24.200 53.5 21.938 17.1 8.921 52.0 22. 091 18.9 17.018 18.0 29.877 18.9 21.271 50.9 19.672 16.0 27. 839 17.4 16.510 18.0 34.38 34.95 35.31 35.30 XI. 71 34.41 34.55 34.67 35.59 34.62 .34. 91 35.48 35.21 34.66 35.20 34.68 34.95 35.31 35.31 34.53 35.52 34.72 34.01 34.63 35.63 34.55 34.38 35.17 34.95 One turn of micrometer^62.01 One (livlsiou of level= 1.28". Total, 106 observations on 76 ps Latitude of Station No. 10 = 31 Latitude of Monument No. 98 = ■ Station No. 10 was on 19' 34.84" ±0.1 31° 20' 04.67". tbe east side t ■ tlie San Pedro River ; Monument No. 20 — Emory — was t about 1 mile northwest from the station. Near the station is a pile of stones, with Inscription plates, boundary monument when locating the station. "Weight for pairs on which 2 observations were made, 1.0; one observation, 0.8. The mean place for 1892, as used in the latitude computation, was for star No. 63, 18° 40' 50.9" : for No. 37, 58" 23' 15.8" ; for star No. 74, 57° 25' 37.4", and for star No. 86, 63'^ 8' 16.5". 92 UNITED STATES AND MEXICAN BOUNDARY. Station No. 11, 1 mile east of La Noria, Aria., near Monument No. 111. Datb. Star No. N.or S. Microm- eter Level. fitar No. N.or S. Microm- eter Level. Latitude, reading. N. S. reading. H. 1892. (. d. d. t. d. d. Nov. 2 576 R. 20.545 21.6 53.8 578 N. 20,303 52,3 19.8 56. 73 576 S. 19. 800 20.0 52,2 678 N. 19, 602 54.0 21,0 57.75 580 s. 29. 542 21.0 53,8 682 N. 11.864 52.8 19.9 07. 28 5 580 s. 28. 521 18.6 55.3 682 N. 10.883 67.1 20.0 .57. 95 584 N. 29. 048 54.9 22.0 586 S, 12, 920 22.0 54.8 57.74 n 591 N. 23. 320 62.0 19.0 594 S. 18, 760 18.8 51.9 57,19 591 N. 22. 991 51.7 16.9 594 R. 18, 330 13.4 48.8 66.92 2 595 N, 18.823 54.9 21.5 596 S. 23.618 21.8 55.0 57.70 595 N. 17. 459 50.9 15.4 596 S. 22. 213 16.5 61,0 57.10 2 599 N. 22. 457 51,2 17.3 602 s. 18. 050 16.8 50.7 57.07 N. 21.618 50.9 15,0 602 s. 17. 191 14,0 49.9 57.43 603 N. 31.031 51.9 18.0 608 s. 11.230 17.7 61.9 57.52 2 609 S. 16.568 20.9 55.0 611 N. 25. 102 56.8 22.3 58,08 609 s. 15.356 17.0 53.5 611 N. 23.930 54.3 17.8 57.02 2 613 s. 22. 959 19,0 53.3 615 N. 18. 920 54.0 19.8 57.17 613 s. 22.379 17.9 54.7 615 N. 18, 360 56.1 19.2 57.65 618 N. 32. 312 54.8 20.2 620 S. 9.880 19.0 63,2 58.22 , S. 12. 880 17.9 52,0 5 N. 29, 709 52.8 18,3 57.16 , 9 N. 20. 950 .54.0 19.9 14 S. 19.940 17.9 52,4 50. 60 2 17 S. 19.520 19.0 54.1 23 N. 22, 154 65.0 20.0 57. 60 2 27 N. 19. 240 52.8 18,0 28 S. 23,420 16.7 51.0 67,31 2 36 S. 12.929 19.9 54.7 39 N. 29. 070 56.8 21.0 57,03 46 N. 11. 049 56.1 20.3 51 S, 32.241 18.4 63.2 57,81 , 53 S. 17.940 19.0 53.9 60 N, 21.823 .56.2 21.5 57.97 64 N. 21.204 53.4 18,6 67 S. 21. 529 17.0 62.0 56.72 2 73 S. 24.160 21.1 56,2 78 N. 15.219 58.3 22.8 58.37 85 N. 22.689 54.9 19,0 91 fi. 19. 280 17.0 53.0 58.06 5 85 N. 21.481 55. 5 14.2 91 R. 18.099 14.8 56.1 57,63 94 N. 18. 529 53.3 17.9 105 S, 23. 890 15.9 51.3 57, 52 2 112 N. 17.320 5.3.8 18,5 120 s. 24. 210 18.1 53.0 57.30 123 N. 28. 530 63.5 18,9 1.13 s. 13.381 17.8 52.0 57,68 137 S. 21.611 17.0 51.2 139 N. 19. 120 53.0 18.6 57.04 137 s. 20. 887 17.0 59.0 139 N. 18. 360 58.6 16.7 57.78 2 142 N. 22.882 52,7 18.1 147 S. 18.382 15.7 50.1 57,93 153 R. 12. 450 19,8 54.2 166 N. 29. 240 53.0 18.5 57.43 153 S. 12.229 18.0 65.2 160 N, 29,039 55.1 18.1 57,70 165 S. 12. 581 18.4 53.2 167 N. 28. 102 62,0 17.1 57,28 3 165 s. 13. 280 18.0. 55.3 167 N. 28.821 55.7 18.1 57, 60 504 s. 32.603 22.0 53.7 507 N. 9,112 53.9 22.1 57,41 504 R. 31. 282 19.9 55,1 507 N. 7,738 63,1 17.6 67,42 3 509 N. 24.347 58,5 26.8 512 R, 16,538 25.3 57.3 57.52 514 N. 27. 942 54.1 22.0 517 R. 14.340 20,9 62.9 56,95 519 R. 14.792 21.3 53.3 521 N. 28.281 54.8 22.7 67,10 523 S. 18. 462 19.0 51.0 628 N. 23.311 52.3 19.9 57.67 531 S. 28.240 19.0 51,8 535 N. 13.889 53.2 20.9 57.14 531 H. 27. 361 15.1 54,3 535 N. 13, 040 57.2 17.9 57.02 3 537 S. 19.010 18.2 51,0 538 N. 23, 430 52,1 19.2 66.69 537 S. 17.683 18.9 63,2 538 N. 22,089 53.7 19,0 56,69 3 539 S. 12.070 17.1 50,0 543 N. 30, 240 61.0 18,0 56,29 546 s. 31. 120 21.1 54,1 547 N. 11, 599 55.0 22.0 56.64 g 546 R. 29. 431 18.3 50,0 547 N. 9.891 49.2 17,8 66.45 3 550 S. 24. 080 18.1 51,6 553 N. 18. 762 52.9 19.3 57.45 556 N. 26. 320 52.8 19.3 557 R. 14.759 17.9 51.0 67.49 3 560 N. 32.001 64.1 20.9 564 .S. 10. 320 18.6 52.1 57.25 566 20, 268 21.0 54.7 568 N. 21.338 54.0 20.2 57.31 3 671 R. 15. 389 18.5 52.1 674 N. 27.673 51.4 17.8 57.48 3 577 S. 15. 060 , 17.1 51.2 579 N. 27.760 50.1 16.1 57.35 5 577 S. 13.469 18.0 64.2 5T9 N. 26. 200 55.1 18.3 57.60 3 581 S. 20. 330 18.0 B2,l 583 N. 21.678 51.8 17.7 57.05 681 S. 19. 100 17.8 51,0 583 X. 20.483 53.1 19,8 57.90 3 585 s. 17. 044 18.0 52,1 588 N. 25.500 61.5 17.1 67.06 3 592 X. 15. 829 63.1 18.9 593 S. 26.172 19.2 53.4 57.14 5 692 N. 15.269 64.3 17,0 593 s. 25, 590 17.8 54.9 56.37 3 597 s. 28. 270 16.2 50,9 598 N. 12, 210 50,6 16.0 57.23 5 597 R. 28. 309 21.9 59.0 598 N. 12. 268 60.0 22,9 57.65 3 600 N 12.235 52.2 18,0 601 R. 29, 561 19.0 53,2 57.36 5 600 N. 11.290 53.6 16,6 601 R. 28, 591 16.9 63,8 57.23 3 604 N. 19. 261 52.0 17.7 606 S. 21. 910 18.0 52.2 57.49 8 604 N. 18.710 52.5 16,5 606 S, 21.316 16.0 52.1 57.17 3 610 S. 32. 161 17.7 52.1 012 N. 9.739 50,9 16.1 56.96 JJov. 8, star 594 observed 16" late: Nov, 2, UNITED STATES AND MEXICAN BOUNDAEY. Station No. 11, 1 mile east of La Nuria, Ariz., near Monument No. Ill — Continued. 93 Microm- eter reading. Level. N. s. (. d. i 31.740 17.6 55.1 15. 720 19.2 54.0 16. 781 17.0 52.0 13.341 53.8 18.9 28. 180 53.6 18.8 23. 145 53.1 18.2 27.74C 55.8 20.7 16.442 17.9 52.8 27.052 54.8 19.9 12. 970 51.7 16.8 23.530 52.7 17.3 20. 014 54.1 18.8 28. 148 53.8 18.0 22.430 18.2 54.5 21.490 18.0 56.6 24.220 18.0 55.0 23.639 16.7 56.0 19. 110 55.2 17.0 17.565 56.0 18.0 16.549 55.5 16.0 l2. 1.58 21.0 52.7 21.570 50.4 17.9 21.561 53.7 16.6 19. 091 52.3 19.3 18.491 53.0 16.9 24. 369 16.1 50.1 24.714 15.5 54.3 10. 590 17.1 51.2 11. 075 52.2 17.7 11.070 47.8 16.2 13.679 17.3 52.8 12. 199 50.4 15.0 12.242 49.0 17.0 27. 710 17.8 53.1 27.810 19.8 51.7 28. 391 19.0 55.0 27.888 54.3 18.0 13.389 53.1 15.9 13.210 52.9 18.3 12 330 18.1 55.1 17. 642 19.7 57.2 27.058 17.1 55.1 26.982 15.0 52.2 29. 160 14.9 53.0 28.602 17.0 54.6 26. 889 17.8 57.7 32. 159 56.1 15.8 25.719 14.6 55.1 15. 709 54.9 13.6 16. 673 15.6 57.0 18. 322 15.0 66.7 20. 611 13.9 55.9 23.249 19.7 51.9 30. 865 16.0 53.6 16.713 53.4 16.0 17.831 56.7 17.0 Microm- eter reading. 9.351 26.398 25. 201 27. 849 14. 910 19. 185 13. 893 25. 090 15. 814 29.491 18.192 21. 950 14. 140 19. 332 18.451 17.342 16. 781 22.745 23. 56] 22. 560 29. 738 16. 910 16.841 21. 889 21.231 13. 579 13. 991 30. 470 26. 804 27. 601 27.651 11.728 11. 822 10. 520 12.653 26. 120 13. 815 9.952 9.450 12. 360 7.620 13. 752 24. 901 22.928 21. 18. 640 15. 070 9.452 22. 860 23. 052 Nov. 8, star 522 observed 19- late. One turn of micrometir = 62.124". One division of level = 1.28". Total, 126 observations on 92 pairs. Latitude of Station No. 11 =31° 19' 57.38" i 0.03". Latitude of Moniunent No. Ill = 31° 19' 57.58". Latitude Station No. 11 was 2.0 meters east and 6.2 meters south of Monument No. 111. Weight for pairs on which 2 observations were made, 1.0; one observation, 0.6. The mean place for 1892, aa used in the latitude computation, was for star No. 28, 14° 53' 10.3" 123, 35^ 40' 04.2" ; for star No. 147, 24° 50' 04.1" ; for star No. 167, 62° 51' 58.2" ; for star No. 37, 58° i star No. 65, 460 26' 59.8", for star No. 74, 57° 25' 37.4"; for star No. 86, 03° 08' 16.5"; for star No. 25' 24.8". 16.8 54.2 54.2 54.0 56.2 I 17.9 54.9 I 51.8 j 53.2 54.3 53.9 17.9 20.7 18.6 15.9 54.8 56.0 56.2 23.0 [ 52.2 I 53.9 54.0 53.2 57.3 12.9 55.1 56.99 57.32 57.98 57.32 57.74 57.18 67.80 57.04 56.99 57.74 58.13 57.16 57.72 57.41 57.40 57.27 66.93 57.35 57.18 57.42 57.24 56.95 56.90 66.82 66.84 57.19 57. 21 57.36 57.48 57.37 57.11 56.72 57.03 57.67 57.27 57.46 57.31 57.92 .. 91, 11° 46' 14.2" star No. 52, — 1° 1.3", and for stai 94 UNITED STATES AND MEXICAN 150UNUARY. Station No. 12, Nogales, Ariz., near Monument Ko. 122. Date. Star No. N.or Microm- eter Level. Star No. N.or S. Microm- eter Level. reading. reading. 1892. t. d. d. t. d. d. Nov. 19 580 S. 29. 258 20.8 54.0 582 N. 11.349 52.6 19.0 4.83 23 580 S. 28. 724 17.7 52.0 582 N. 10.881 54.1 19.0 5.01 19 584 N, 28.426 05.1 21.1 580 S. 12.491 21.7 5S.9 4.01 58i N. 28, 343 50.0 21.7 580 S. 12. 420 22.9 51.1 4.11 19 591 N. 22.998 52.8 18.0 594 s. 18.649 18.7 53.3 4.48 26 591 N. 22. 330 48.0 19.2 594 s. 17. 995 20.7 49.2 4.54 19 603 N. 30. 430 54.9 18.9 608 s. 10. 808 17.9 54.1 4.77 26 603 N. 29.627 50.0 20.8 608 s. 9.979 21.0 50.9 3.35 609 S. 15. 879 19.0 55.2 611 N. 24.201 .55.3 19.0 5.04 26 609 s. 15.811 21.5 51.1 611 N. 24.142 50.2 20.0 4.36 613 s. 22. 870 17.0 53.7 615 N. 18. 648 54.0 17.1 3,88 26 613 s. 22. 610 20.0 50.1 615 N. 18.340 49.8 19.3 6.33 618 N. 30.701 54.2 17.8 620 S. 8.451 17.0 54.0 4.75 618 N. 31.008 50.3 19.9 620 s. 8.709 20.2 51.0 4.90 19 S. 12. 000 17.0 .541 5 N. 28.649 54.2 16.9 3.97 9 N. 20.491 54.0 16.2 14 s. 19. 680 15.9 54.0 3.27 20 9 N. 20.080 51.2 19.9 14 s. 19.300 20.3 52.2 4.22 17 S. 18.836 17.0 55.1 23 N. 21.262 55.0 16.3 4.94 19 27 N. IS. 679 54.1 15.6 28 S. 23.061 16.0 54.9 3.98 19 36 S. 12.652 15.0 54.0 39 N. 28.591 54.0 14.7 4.27 19 44 S. 27.359 19.0 58.9 49 N. 12. 660 58.3 18.7 5.08 19 53 s. 17.579 22.0 52.3 60 N. 21. 228 51.7 21.0 5.05 53 s. 18. 350 16.0 49.6 CO N. 22. 003 47.9 14.2 5.04 19 64 N. 19.911 50.9 20.0 67 S. 20.459 20.1 51.1 4.53 74 N. 11.724 50.9 19.9 80 s. 28. 450 20.0 51.1 5.77 N. 21.589 49.4 18.1 91 s. 18.371 18.3 50.0 4.44 23 85 N. 21.760 54.0 14.0 91 s. 18. 549 14.1 54.2 5.32 N. 17.401 48.8 17.0 105 s. 22.973 17.4 49.2 4.58 23 94 N. 17 420 54.9 14.9 105 s. 23. Oil 10.0 56.1 5.21 N. 16.429 51.0 19.0 120 s. 23.520 19.2 51.7 4.90 123 N. 28.299 51.8 19.2 133 s. 13.324 19.3 52.0 4.19 137 S. 21.032 19.7 52.0 139 N. 18. 330 51.1 18.7 4.48 22 137 s. 21.45* 18.0 53.1 139 N. 18. 768 54.0 18.8 5.52 142 N. 21.929 53.2 21.0 147 s 17. 639 21.0 54.0 4.53 19 153 S. 11.423 19.0 52.0 1,56 N. 28.041 50.9 17.9 4.75 160 s. 23. 700 20.4 53.4 102 N. 16.613 52.7 19.2 5.31 22 100 s. 23.787 18.0 53.9 102 N. 16.741 54.1 18.0 5.04 19 165 s. 12.490 19.2 52.9 107 N. 27. 821 52.0 18.8 5.12 N. 18.189 65.0 21.0 188 S. 22. 060 21.5 55.7 6.00 23 186 N. 18.110 51.7 20.9 188 s. 21.955 21.0 52.1 5.07 548 S. 14. 069 20.3 48.3 549 N. 26 902 47.8 19.2 4.48 22 548 s. 13. 551 19.0 on.i 549 N. 20. 349 48.0 16.4 4.63 21 550 s. 23.439 23.8 52.1 553 N. 17.851 .52. 1 23.7 4.81 21 556 N. 25. 230 49.9 21.0 557 S. 13. 908 19.2 48.2 4.90 22 551 N. 27. 122 51. 6 19.9 555 s. 10.990 18.1 50.6 3.80 22 558 S. 27. 778 20.0 52. 3 559 N. 11.518 53.0 20.0 5.20 23 558 S. 28.219 19.2 50.2 559 N. 11.929 49.9 18.8 5.69 500 N. 3D. 930 52.0 19.0 504 S. 9.477 16.9 50.3 4.27 22 566 R. 19. 069 18.0 51.7 508 N. 19.959 53.2 19.4 4.64 22 571 S. 14. 322 17.9 52.0 574 N. 20.462 53.9 19.3 3.74 22 576 S. 20.041 19.2 54.1 578 N. 19. 621 55.1 19.9 4.53 26 576 s. 20. 250 24.0 52.0 578 N. 19. 793 51.8 23.2 4.73 22 581 s. 19. 951 19.3 55.2 583 N. 21. 120 56.3 20.3 4.15 26 581 s. 19.479 21.5 50.0 583 N. 20.607 49.6 21.0 4.38 585 s. 16. 101 10.0 52. 2 588 N. 24.440 54.0 17.0 2.91 22 592 N. 14. 980 54.4 17.6 593 S. 25.482 15.7 52.8 4 39 23 592 N. 15. 040 51.3 15.5 593 s. 25.551 15.0 51.1 3.80 22 595 N. 17. 647 54.0 16.7 590 s. 22.589 14.8 52.1 4.83 26 595 N. 17. 270 49.9 21.0 590 s. 22.279 21.5 .50.4 5.43 22 599 N. 21. 680 53.1 15.0 002 s. 17.439 13.1 51.3 4.40 26 599 N. 21.769 49.9 20.6 602 s. 17. 592 21.0 50.9 4.73 22 604 N. 18. 508 54.9 10.2 606 s. 21.370 53.2 4.72 22 610 S. 31. 098 15.4 54.5 612 N. 9.101 55.9 16.9 6.09 23 610 s. 31.878 18.0 55.3 612 N. 9.301 50,0 18.8 4.72 22 614 s. 14. 968 16.3 55.8 619 N. 25.401 57.9 18.0 8.04 22 3 s. 16. 569 22.0 53.2 8 N. 24. 881 55.5' 24.2 4.70 22 12 N. 12. 519 52.0 20.8 16 S. 27.209 19,0 50.3 6.57 22 18 N. 26.961 52.1 20.4 29 s. 13. 801 18.0 50.2 4.33 22 37 N. 22. 092 48.9 10.2 45 s. 18. 300 15.1 48.0 5.10 26 37 N. 22. 079 53.9 21.0 45 3. 18.290 22.3 55.3 4.01 22 46 N. 9 981 50,0 17.0 51 s. 31.308 16.6 49.3 5.20 UNITED STATES AND MEXICAN BOUNDARY. Station No. IS, Nogales, Ariz., near Monument No. /2J— Continued. 95 Microm- eter reading. 24.511 23. 708 22.290 19.301 26.780 22.541 15. 070 16. 780 27. 787 27. 509 14.821 17.650 16. 595 17.088 27. 118 29. 802 31. 120 26.570 32. Ill 26. 119 20.918 18. 518 26.288 11. 033 23. 382 13. 880 21. 602 13. 392 15. 570 17. 931 21.373 24. 179 11. 332 24. 341 15. 010 15. 390 17. 510 17. 159 21. 358 12. 950 18.739 13. 060 24. 967 23. 048 22. 790 23.304 27.411 10. 622 14. 219 26. 195 26. 141 11. 979 28. 581 27.881 23. 173 13. 720 10.419 9.452 23. 021 22. 483 13. 028 12. 873 25.441 18. 808 21. 903 15. 009 29. 140 14. 918 26. 305 16. 142 25. 799 24. 948 21. 325 18. 112 14. 502 1.340 14.3 53.0 17.0 56.0 54.5 54.8 57.8 49.9 49.9 51.0 21.0 53.6 52.0 50.9 49.8 53.2 54.9 18.9 16.2 16.0 52.9 4.57 5.08 5.14 4.94 4.61 5.37 5.08 5.48 5.32 3.25 5.18 5.43 5.50 4.50 4.97 4.36 4.12 One turn of micrometer=62.124". One division of level = 1.28". Total, 121 observationa on 93 pairs. Latitude of Station No. 12 = 31^ 20' 04.77"+ 0.04". Latitude of Monument No. 122=31^ 20' 00.73". Latitude Station No. 12 was 124.4 meters north and 170 meters east of Monument No. 122, in the grounds Montezuma Hotel. Tbe latitude and longitude piers, bnilt of brick and cement, were left in position. Tliese same i tbe year by tbe Ooiist and Geodetic Survey. Weight for ptiirs on wliich two observations were made, 1.0; one oliservation, 0.7. The mean place for 1892, as used in the latitude computation, was, for star No. 28, 14° 53' 10.3"; for star No. 74, 57° 25' 37.4 No. 91, 11° 46' 14.2" ; for star No. 123, 35 ■ 40' 04.2" ; for star No. 147, 24° 50' 04.1" ; for star No. 167, 62° 51' 58.2" ; for star No. 37, 58 ■ 23' 1 for star No. 65, 46° 20' 59.8" : for star No. 86, 63° 08' 16.5" ; for star No. 99, 34° 28' 34.3" ; for star No. 135, 9° 39' 28.3" ; for star No. 192, 4 24 8", and for star No. 52, —1° 33' 06,1". built and used e.arlier for 6 96 UNITED STATES AND MEXICAN liOUNDARY. Station jN'i). 13, Yuma, Ari:., in corral of qiiartermaster'a department. Microm- reading. 28. 819 22. 024 21.747 22.464 22.259 21. 230 21. 070 21. 027 30. Oil 29. 759 29. 725 30.127 23.511 24.010 23.921 23.871 I 29. 669 29.370 30. 184 22. 186 22. 210 10.741 10. 708 32. 274 32.76 23. 308 24. 160 23. 763 23.675 31. 632 31. 468 16.480 24. 216 24. 241 18.911 18. 638 21.640 21.412 15. 860 15. 930 14. 909 16. 143 16.216 16. 511 13. 650 9.640 10. 071 9.849 13.381 17.0 52.3 18.0 16.7 18.9 15.7 21.6 18.9 50.2 49.0 18.7 19.0 53.0 50.2 51.8 53.3 53.0 52.5 17.2 53.9 53.2 49.6 19,9 50.8 49.7 50.7 51.1 51.2 52.0 17.2 53.2 53.1 Microm- eter reading. Level. Latitude, N. S. 32=> 43'. (. d. d. 19. 840 51.0 18.6 34.93 15.752 18.9 51.3 34.61 30. 341 61.2 18.2 34.12 29. 160 50.9 18.0 34.67 28.761 49.3 18.0 34.19 28. 527 47.9 16.8 34.20 12.109 56.0 23.9 34.64 12.619 49.9 18.8 34.86 18.780 15.7 48.7 34.47 18. 569 18.1 49.7 .34.92 17. 680 53.3 20.2 34.38 17.410 49.3 18.0 34.53 19. 223 17.9 51.1 34. 56 19. 119 18.6 50.1 34. 90 19. 037 19.2 50.3 34.46 11. 200 50.3 17.9 33.63 10. 986 65.1 21.6 35.03 10.879 51.0 19.3 34.66 11.318 51.9 20,8 34.86 17.319 60.8 17.9 34.41 17. 852 ,53.1 19.0 34.72 17.708 51.2 19.7 34.67 17. 702 52.7 21.1 34.49 10.283 51.7 18.9 35.14 9.996 50.9 19.0 34.69 10. 841 49.0 17.7 35.06 18. 371 51.0 17.9 34.98 18.408 49.1 16.9 34.66 30.890 17.6 52.8 34.30 .30.889 18.8 50.9 34.52 6,651 18.8 50.6 34.59 7.140 18.9 51.8 34.52 15.718 19.3 53.4 35.28 16.601 19.0 54.2 35.15 16. 192 19.0 51.6 35.07 16. 493 16.8 60.9 34.82 7.971 19.2 63.2 34.28 7.790 18.2 50.9 34.13 23. 839 18.6 54.0 34.68 16. 781 53.5 18.9 34.03 16.809 51.9 15,9 33.73 16.918 52.2 17.0 34.78 16.780 50.9 17.0 34.32 21.599 21.7 57.0 34.78 21.311 17,8 52.9 34.96 18, 272 19.6 55.3 34.69 18. 006 17.9 53.0 34.15 24. 160 54.1 18.6 34.31 24. 250 53.3 17.9 34,43 25. 938 16.0 51.4 34.12 20.219 18.9 54.8 34.16 26.483 16.0 61.9 35.18 26.367 15.9 51.2 34.66 25, 650 17.0 52.6 34.66 25,692 15 3 51.7 34.40 26. 008 16.0 51.7 34. 7B 28. 683 54,1 17.9 35.39 30. 350 53.2 17.9 34.51 30.800 53.7 17.7 34.26 29. 839 15.8 52.0 34.68 26.960 17.0 62.6 34.96 27. 069 20,0 66.3 34.66 UNITED STATES AND MEXICAN BOUNDARY. 97 Station Xo. 13, Tun nl of quartermaster's department — Continued. 1893. Jan. 18. Z_L 24.034 17.0 53.6 23.840 16.0 52.8 9.03U 1.5.4 51.8 9.431 16.3 5;i.2 9.159 18.0 54.2 9. 033 17.9 54.8 30. 276 53.0 10.3 30. 468 52.7 15.6 30. 674 53.2 17.0 30.500 55.0 17.5 19. 120 18.0 S4.8 19.252 16.9 54.1 18.759 17.0 53.0 18.799 16.6 53.9 8.900 56.5 19.0 8.470 53.3 17.3 27.481 15.9 53.2 27.952 16.1 53.9 12.681 15.0 53.0 13. 272 15.7 51.8 18. 349 17.0 54.3 17. 978 15.1 53.3 10.401 18.6 56.2 9. 672 16.1 52.3 26.558 53.4 16.0 26. 586 53.0 15.6 25.680 53.2 16.9 20.851 55.1 16.6 13.891 53.3 15.9 14.111 55.1 16.0 22. 561 16.5 53.9 24.019 57.4 19.2 13. 925 54.6 16.9 14. 149 55.1 17.7 21.932 16.8 55.0 22.531 16.0 53.9 22. 501 18.1 56.2 16. 200 55.5 17.0 15. 892 54.8 17.0 15.859 54.0 16.0 26.790 17.1 55.9 26.811 15.6 5:'. 3 26.560 14.8 52.8 One turn of the micrometer^62.124". One division of level=1.28". Total, 105 observations on 45 pairs. Latitude of Station No. 13 = 32o 43' 34.69" ±0.03". Station No. 13 is in the east room of the adoln- h 1 1 i 1 . 1 1 ii - w h i . ■ 1 1 fi .r Department, U. S. A. It is markfd by a brickand ctnK ni i.i.-i w li nh party. The latitude computation for this station iii;i'i.' t\\<- |.TnKiM.- meaii of two star declinations J:0.02". As it is certain tlijt tli. dci liii;. assigned on the assumption that tlie probable error of tho mean of two Weiglit for pairs observed once, I.O; twice, 1.4; three times, 1.6; The mean place for 1893, as used in the latitude computation was No. 99, 34° 28' 51.5"; for star No. 123, 35° 40' 20.3"; for star Xo. 13.5, 9° 3 for star No. 192, 47° 25' 34.7" ; for star No. 223, 60° 17' 06.5" ; for star No 46° 49' 45" Microm- Level. rea!u;.g. N. s. (. d. d. 17.259 53.1 16.6 17.078 53.0 16.3 30. 809 62.2 16.0 31.219 53.3 16.7 30.968 55.1 19.0 30. 811 65.1 18.0 9.709 15.0 51.7 9.921 14.9 61.9 21.560 21.101 21. 125 31.530 31. 081 12. 683 13.121 28.110 26.719 22.391 22.012 30.929 30.250 14.740 j 14.799 13.849 j 26.729 19. 309 16.899 27.411 I 27.528 17.958 18.520 I 18.480 24.870 24.600 24.574 13.990 14.029 16.4 54.0 54.0 17.0 j 54.9 j 52.7 16.3 16.4 ! 16.5 ' 17.0 16.3 21.0 18.0 51.3 j 52.0 ! 51.2 i 53.8 j 54.3 56.3 54.0 17.2 34.66 35.02 34.90 34.53 34.71 35.21 34.48 35.65 34.58 35.07 34.57 34.92 35.98 35.43 34.15 34.91 35.28 35.31 34.46 34.43 35.58 34.68 34.52 35.66 34.39 33.87 34.98 34.71 34.50 35.69 34.87 34.71 34.69 35.08 t of the north wall of the old corral of the Quartermaster's and used in 1892 by a Coast and Geodetic Survey longitude ;i single observation :»:0.28", and the probable error of the irs are much larger, the weights for the separate pairs were ions was 0.9 of the probable error of a single observation. IS, 1.7. No. 91, 11° 46' 31.8"; for star No. 97, —0° 51' 13.2"; for star for star No. 147. 24° 50' 18.3"; for star No. 107, 62° 52' 10.2"; 20' 11.8"; for star No. 227, 41° 05' 21.4"; and for star No. 230 UNITED STATES AND MEXICAN liOUNDAKY. Station No. 14, 20 miles helow Yuma, Ariz., near Monument No. 204. Z_L Microm- 4Canielop I Ami J E.J. 22 H. J. 51 Aiiri J.Orocn 1460 23. 178 18. 399 29. 361 26. 741 12. 930 22. 590 9.851 24. 958 8.169 9.494 52.9 15.021 54.2 15.820 16.3 16.516 18.6 24.772 54.0 16. 204 52.0 10 Mono- cenitis I eGemin / tion that in fact e = 0.9 c. Most of the observations were made under meteorological conditions very favorable to accui ?ite observation. The typical working night was perfectly clear, with no strong winds, and with air so dry that no dew fell even during the cool morning hours. Under such conditions the st?Ts, except near sunset, showed very brightly and with little or no twinkling or dancing as seen reith the telescope. The door of the observatory tent was kept open and the circulation of air through tlaor, sides, roof, and door of the tent usually kept the temperature inside the tent within less than a degree centigrade of the temperature outside. This seemed to be an important factor in control- ling the apparent steadiness of the stars; for at Nogales in a wooden building and at Yuma in an adobe building, with the outside meteorological conditions just as favorable as before, there was a much greater difference between the inside and outside temiierature, and the stars showed a marked unsteadiness as compared with their usual appearance. The value of micrometer was determined at every station save No. 14. In each case, except at Station No. 11, ti-ansits across the thread of Polaris near elongation were observed, the thread being set at each half-turn in succession for the twenty turns nearest the middle of the field of the telescope and the time of transit observed by eye and ear. At Station No. 11 similar observations were made upon A UrsiB Minoris. The value of micrometer was computed from these observations by the formula- of the appendix already referred to. (Coast and Geodetic Survey Report, 1880, Appendix No. 14.) During the first set of observations, on February 15, 1892, the quarter-turns were also observed on the middle ten turns to detect periodic error in screw value. The values of the four quarter-turns as derived separately agreed with each other within the respective probable errors, and thus gave a nil result. UNITED STATES AND MEXICAN BOUNDARY. Summary of mkrtuntltr (leteiminaliiiiis. 103 station. Date. Value of turn. Probable error of turn. Temper- dnring observa- tion. No 1 No I Fell 15 1892 1 (-1. 19 1892 62.227 62. 107 ±0.008 i; .010 ° 9 No 1 Feb J7 1892 62. 223 ± .012 10 No 3 Mir 23 1892 62.163 ± .014 12 No 3* Apr 10 1892 1 62.118 ± .008 26 No 4 M>r 22 1892 62. 105 t .006 7 No 5 Maj 30 1892 62.093 ± .008 16 No 6 Juuo21 1892 62.101 ± .017 26 No 7 JuU 26 1892 62.078 ± .009 19 No 8 Vug 15 1892 62. 099 i .017 23 Nc 9 Sei.t 7 1892 62.164 + .010 23 No 10 (Jet 4 1892 62.016 ± .011 24 No 11 Nov 8 1892 62.025 ± .016 ■2 No 12 Nov 25 1892 61.898 ± .014 8 No 13 Jan 25 1893 61.994 ± .031 10 No 15 Si.pt 25 1893 62. 059 i.009 16 * Illumination from aky only. The observed microaietei- value apparently is not a function of the temperature at the time of observation. The latitude at Station No. 1 was computed with the value of one turn=62.225", the mean of the observations of February 15 and 27, rejecting the observation on February 19. The value of one turn as derived from the latitude observations at the station is G2.207". At Stations No. 2 to No. 10, and No. 15, the value of micrometer as observed at the station and shown above was used in computing the latitude. The mean of the first twelve values of one turn in the above table is 62,124". At Station No. 11 the latitude observations, when reduced with the value, 02.025", as observed at that station, showed a total range of 3.85", apparently systematic with reference to micrometer difl'erence.s. The micrometer value was then derived from the latitude observations and found to be 62.123". As this corresponded very closely with the mean value given above, the observed value at the station was rejected and the observations reduced with said mean value, 62.124". The total range in the results for latitude as thus computed was 2.08". At Station No, 12 the values for the latitude showed an abnormal range when reduced with the value of micrometer as observed at the station, namely, 61,898". The value was then deduced from the latitude observations and found to be 62.086". The flual latitude computation was made with the meau value mentioned above, 62.124". At Station No. 13 a similar condition of afl'airs was again found. The latitude observations, as reduced with the value of micrometer observed at the station, 61.994", showed a range of 4.10". The micrometer value, as deduced from the latitude observations, was 62.120". The final latitude computation, as made with the mean value, 62.124", showed a total range of results of 2.35" only. No adequate explanation was found for the apparently erroneous observations of micrometer value at Stations No. 11 and No. 12. At Station No. 13 the observations were taken in an adobe building; the temperature was remarkably difiereut inside and outside; the line of sight passed through a comparatively small hole in the wall; the apparent motion of the star was unsteady and the computed probable error of the result is two or three times as large as for similar observations at other stations. The micrometer value was deduced from the latitude observations in the cases mentioned above, as follows: Let cp be the mean latitude (as deduced with an approximate micrometer value), from pairs on which the micrometer difference (S-N) was positive, qj2 the mean latitude from pairs with minus micrometer diii'erence, D, the mean of plus micrometer differences, and D^ the mean of minus micrometer differences. Then the correction to the approximate value for one turn of micrometer is 2(cfH-^W= i 0.034". If the same number of observations were taken upon 18 pairs, 6 observations per pair, c and e3 remaining- the same, the probable error of the final result would be v (0.23V- (0.22V' 108+18^ ^ ■v/(0.022)^'+ (0.052)^= ± 0.056" An injiuitc number of observations on 18 such pairs would give a result with a probable error 0.22 of y-~- = zl= 0.052", that being the error from declination alone. Even if the probable error of a single observation were twice as great as in the actual case, namely, ±0.46", and d were ± 0.22" as before, 108 observations oa 72 pairs would give a result with a probable error of V 'w" + '"7?''= a/(O.OM)H (0.026)-'= ± 0.031" a more accurate result than could possibly be obtained from only 18 such pairs observed any number of times with any degree of accuracy. In cases in which the accuracy of the available star places is not as great as for the list here used there is still greater advantage in the method of observing a large number of pairs. This method of work involves the necessity of computing a greater number of mean star places than usual; but the cost of that part of the work is but a small portion of the total cost. A considerable portion of this list would have been needed even if the ordinary plan of work had been followed. An accidental, but important, advantage of the method of observing many pairs is the way in which partially cloudy nights and isolated clear nights in the midst of a cloudy season may be utilized. If one is observing in the ordinary way on a list of, say, twenty pairs, only about three or four hours of a perfectly clear night can be utilized, even though there may be great anxiety to finish the work at the station. On the otlier hand, the observations are entirely prevented for the night if it is cloudy during the three or four hours covered by the limited list, and the whole night is lost even though it may be clear during the greater portion of the time. At Stations jSfo. 5 to Xo. 12 and No. 15 the available pairs formed a double (and in some cases even a triple) list extending through most or all of the available hours of darkness. At these stations there was not the slightest difficulty in utilizing partially cloudy nights, or in utilizing all the hours of darkness on clear nights when there was a necessity for rapid work. At Station No. 6, 49 and 4S observations, respectively, were taken on the nights of June 14 and 16, thus nearly tinishing the work of the station in two nights. At Station No. 15 the observations were greatly delayed by clouds. When the weather at last cleared, 72 observations were taken on the nights of September .30 and October 1, and the work at the station finished on tlie 2d by 22 obser- vations. Taking most or all of the observations for a station on one, two, or three nights will decrease the accuracy of the result if there are constant errors peculinr to each nif/ht, but not otherwise. The results, as classified by nights and given below, serve to show that for this series of observations the discrepancies between the results for different nights are no greater than should be expected from the accidental errors of observation and declination. The column headed '-Residual" shows the difference between the result for the night and the mean for the station. The column headed "Co (observations oidy)" shows the probable error of the mean result for the night as arising from errors of observation only, neglecting the declination error, or, in other words, the probable error of a single observation divided by the square root of the number of observations on the night in question. 108 UNITED STATES AND MEXICAN BOUNDARY. ::\ Apr 2) 59.40 .59. 39 59.37 only). Ji.m lb luiii 21 7uh 7 Jllh 8 Juh '1 Jllh il Juh J6 Juh 27 Jul} 28 Aug 'I 57.95 58.13 56.68 56.68 66.77 56.58 56.86 56.81 56.62 59.05 58.93 St 10 22 S.97 b.i.< 12 ; 20 0.12 Sipt 11 34 0.08 Oit 1 , 18 34.96 Oct 4| 21 34.73 57. 49 .57. 34 57.32 57.32 Feb 16 I Sept 27 ' Sppt 30 I .14 i UNITED STATES AND MEXICAN BOUNDARY. 10!) The mean value of tlie residuals, or differences between the result for the niyht and the mean for the station, is 0.09". On 31 nights, out of a total of CS, the residual was not greater than the probable error in the result arising from observatiou only. TBI ANGULATION. The triangulatiou near El Paso was intended merely to connect Astronomical Station No. 1 with Emory Monuments No. 1, No. 2, and No. 3, but was extended to couuect with j)rominent buildings in El Paso and Juarez, and with the triangulation of the Coast and Geodetic Survey longitude party at K\ Paso in 1892. The measurements of base and angles were made conjointly by the tangent party under Mr. E. L. Ingram, assistant engineer, and the astronomical party. A base 5.50 feet long w as measured with 20 m. and 50 m. steel tapes on the railroad track near the astrononncal station. During the measurement the tape was placed upon the rail and was therefore supported throughout its whole length. The temperature of the rail, as ret'orded by a thermometer placed against it, was assumed to be the same as the tem[)erature of the tape. The lengths of the tapes used in this and later base measurements were determined in January, 1892, on the mural standard of the United States Weights and Measures Office at Washington, I). C. The lengths were determined with the tapes supported throughout their whole length. Three double measures of the base, each forward and back, using two different tapes and on two dates, by difterent men, gave a range of 0.021 m. The horizontal angles were measured with three different instruments — Wurdemann S-inch repeating theodolite No. 85, Coast and Geodetic Survey 8-inch repeating theodolite No. 149, and Fauth theodolite No. 725 (described as the instrument used for azimuth). The observations were made upon poles at convenient hours of the day, the observing not being confined to the hours of steady seeing. The instrument was usually mounted on its trij)od and was unprotected front sun and wind. The sketch of the triangulation shows which stations were occupied. The average closing error of the triangles was 15.3" and the greatest closing error 20.4". The azimuths and geographical positions given depend upon the observed azimuth and lati- tude at Astronomical Station No. 1 and the longitude observed by the Coast and Geodetic Survey in El Paso in 1892. The tables of geographical positions are given in Chapter IN' of United States liei)ort. The astronomical station was marked by a stone weighing about 250 ])ouii(ls, having a lead plug in the top and sunk just below the surface of the sand. North Base and South Base were marked by stakes about 07 mm. s(|uarf. driven neaily down to the surface. The station on the Federal building is the flagstaff at tlie northwest corner of the tower. The station on the court house is the flagstaff on the dome. The station on the cathedral at Juarez is the large cross. Stations A, B, and C are marked by wooden stakes. At San Pedro River the triangulation consisted of a single quadrilateral, of which one diagonal was the measured base and the other a line joining Astronomical Station No. 10 with a point called A, near Monument No. 98. This quadrilateral served to connect the astronomical •station with the monument and with the tangent to the westward, which begins at A. All four stations were occupied and the closing errors of the three principal triangles of the figure were 8.4", 0.6", and 0.2". The observations were made with Coast and Geodetic Survey theodolite No. 149 and with Fauth theodolite No. 725. The base, 484 m, long, was measured with a 50 m. tape, supported by the ground throughout its length. Four measurements giving a range of 0.024 m. were made just before and after sunset. The temperature of the tape was assumed to be the same as that recorded by a thermometer lying on the ground. The observed latitude of Astronomical Station No. 10 is 31° 19' 34.84"; and the azimuth of the line to A, 12.5° 21' 0.8", (back azimuth = 305° 20' 35.1"). The distance to A was 1,601.3 ni. Tlie latitude of A is 31° 20' 04.92", and its longitude 0"^ 00' 49.40" west of Astronomical Station No. 10. 110 UNITED STATES AND MEXICAN BOUNDARY. Monument No. 98, 8.1 m. west and 7.7 m. south of A, is in latitude 31° 20' 04.67". The astronomical station and Station A are marlied by pine stakes about 65 mm. square. The triangulation at Nogales served to connect the latitude, longitude, and azimuth stations with prominent points in the town, with Monuments No. 12ii and No. 127, and with the instru- mental line which afterwards connected Monument No. 127 with Monument No. 204 at the Colorado liiver. The base, 725 m. long, was measured between the rails of the railroad track just south ot town, at night, with a 50 m. steel tape. The tape was supported throu{;hout its whole length by the ties and ballast. The position of the end of the tape for each tape length was marked with an awl on a zinc plate previously placed in position on a tie or on the head of a stake driven flush with the surface. The temperature was recorded by a thermometer placed on the ballast near the tape. Three measurements gave a range of 0.005 m. The angles were measured with Fauth direction theodolites No. 433 and No. 813. These are twin instruments, the only marked difference being in the style of finish. The horizontal circles, 20 cm. (S inches) in diameter, are graduated in ten-minute spaces and every degree is numbered. The circle is read by two opposite micrometer microscopes. Each half-turn of micrometer head corresponds to 1 minute on the circle and is graduated to thifty divisions (2 seconds each). Hence the sum of the forward and back readings on the head gives the number of seconds of the reading of the circle, except for error of run. The standard or yoke of the instrument is quite low and the telescope will not transit. The observations were made at convenient hours of the day, not being confined to the short hours of steady seeing. As a rule the observations at a station were completed on the first day it was occupied. Poles were used as signals. The instrument was usually supported simply on its tripod, and was not protected from the sun or wind. The routine of observation, as is usual with a direction instrument, consisted of a pointing and reading of horizontal circle for each signal in turn from left to right, and then back again in the contrary order after reversing the telescope. Five positions of the circle, 72° apart, were used. Tlie minimum of observation at a station was one set in each position of the circle, and as a rule the number of sets was between five and ten. The greatest range in the different measurements of any one direction was 21.8" and the mean range 11.8". One triangle had a closing error of 18.9", and all the others closed within 10". The mean closing error was 5.3". Tlie azimuths depend u])on the observed azimuth of the line, azimuth station to azimuth mark; the latitudes upon the observations at Station No. 12, and the longitudes upon the obser- vations at Station No. 12, by the Coast and Geodetic Survey in 1892. The tables of geographical positions are given in Chapter IV of United States Report. The point called "Astronomical Station No. 12 (observing stand)" in the list is tlie center of the tripod, which was built just outside the observatory to support the instrument when measuring horizontal angles. It is 2.22 m. south and 1.28 m. east of the latitude pier and due south of the longitude pier. The latitude of the piers is 31° 20' 4.77". These piers of brick and cement were left standing, inclosed in a small wooden observatory in the grounds at the rear of the Montezuma Hotel. The reference marks at each station were, unless otherwise stated, placed approximately north, east, south, and west from the station mark, and the monuments gi\ en below are from the station mark to each reference. Azimuth station, station marlc 2incli by 4-iuch pine slake, references 1-inch by 1 -inch i)ine stakes, N. 0.831 m., S. 1.025 m., W. 0.844 m., E. 0.989 m. North Base is in the switch yard of the Sonora liailroad, on the prolongation of the center line of the track on last tangent before entering the yard from the south; station and references, 2 inch by 4inch pine stakes, N. 0.975 m., S. 1.077 m., W. 0.899 m. South Base is 9..58 m. eastward from the center line of the Sonora Railroad track; station and references, 2-inch by 4-inch pine stakes, N. 0.765 m., E. 0.845 m., W. 0.7.!4 m. No. 1, station 2-inch by 4-inch pine stake: references, flve-eighths-inch iron rods, N. 1.082 m., E. 1.182 m., S. 1.182 m., W. 1.220 m. UNITED STATES AND MEXICAN BOUNDARY. Ill No. 2, stalion and leferences, five-eightlis-indi iron lods, N. 1.088 m., E. 0.971 ni., S. 0.91.'.) in., W. 0.926 m. No. 3, station and references, five-eightlis inch iron rods, N. 1.140 ni., E. 1.080 m., S. 0.9G6 m., W. 1.110 m. No. 1, station and references, five-eightli.s iucli iron rod.s, N. 0.972 ni., E. 0.976 m., S. 1.017 ni., W. 1.070 m. No. 5, station -l-iuch by 4-inch ])ine stake; references, 2-inch hy 2incli ])ine stakes, N. 1.008 ni., E. 1.171 ui., S. 1.102 III., W. I.(t4] in. No. 6, station and references, five-eighths-iuch iron rods, N. 1.140 in., E. 1.113 ui., S. 1.128 in., W. 1.225 m. No. 7, station and references, tive-eighths-iuch iron rods, N. 1.00") ni., K. 0.930 in., S. 1.000 in., W. 1.152 m. No. 8, station mark five eighths-inch iron rod; reference, NW. to nail in stuiiip 1.254 in., SE. to nail in tree 3.757 m., S W. to nail in tree 6.570 m. B, 4.76 m. south and 4.11 in. west of Emory Monument XIX, station five eighths inch iron rod, reference nails in trees, N. 6.431 m., E. 2.827 m., S. .5.159 m., W. 3.G.34 in. The astronomical party also ran a tangent to the prime vertical at the azimuth station west- ward to a point near Monument No. 127, and determined by intersections from triangnlatiou stations the distances to ten points on the tangent, for the use of the topographical party and the monument party. As a check upon the accuracy of the triangnlatiou it may be mentioned that the azimuth of the line azimutli station to B, as given by the latitudes and longitudes of those stations computed through the wliole triangulation, was 90^ 29' 0.6", while a direct measurement at the azimnth station of the angle between B and the azimuth mark gave for the same line x = 90° 29' 2.7", a difference of 2.1". The triangulation near Yuma, Ariz., served to connect Astronomical Stations No. 13 and No. 14 with each other, with prominent points in Yuma, with Monument No. 207, just west of the Colorado River and the instrumental line westward to the Pacific, and with Monument No. 204, 20 miles below Yuma, and the instrumental line eastward to Nogales. The base, 2,205 m. long, was measured on the mesa just south of Yuma with a 50-m. tape at night. With the exception of certain fractional tape lengths the line was measured with tlie tape supported by the sand throughout its whole length, the very few slight inequalities of the ground having been removed. The base was nearly level, with the exception of two tape lengths at the east end. Here the line rose to tlie top of a rocky hill about 19 m. above the remainder of the base. The ascent was made by two tape lengths on a considerable inclination, the difference of height of the different points of support of the tape being measured with a spirit level. The position of the end of the tape for each tape length was marked with an awl on a zinc plate on the head of a stake driven flush with the surface of the sand. The temperature of the tape was assumed to be the same as that recorded by a thermometer placed near the surface of the sand near the tape. Two measurements of the base made on the nights of January 28 and 30 under very favorable conditions — little or no wind, clouded sky, and nearly constant temperature — differed by 0.007 in. The angles were measured with Fauth direction theodolites No. 433 and No. 813. The gen eral plan of observation was the same as at Nogales. The observations were not limited to the hours of steady seeing. Both poles and heliotropes were used as signals. The instrument was not protected from sun and wind. At Monument No. 204 a tripod and scaffold about 8 m. high was built to jilace tlie instrnment high enough to see over the slight swell of the mesa between that point and Yuma. As before, five positions of the ciri'le were used. The miniinnm ol' observation at a station was one set in each position of the circle, and the actual number of sets was usually between five and ten. The greatest range in the measurements of any one direction was 17" and the mean range 7.2". The greatest error of closure of a triangle was 5" and the mean closing error 2.6". 112 UNITED STATES AND MEXICAN BOUNDARY. The ti'iaugulatioii was adjusted by least squares to satisfy the side and angle conditions. The greatest correction to any observed direction from this adjustment was 2.2" and the mean of the corrections 0.9". The azimuth of the line ^Monument 204- A.zimiith Mark, as computed tlirough the triangnlation from the observed azimuth at Yuma is 178° 31' 20". The azimuth of the same line as observed at Monument 204 is 178o 31' 21". In the table the azimuths and latitudes depend upon the observations at Yuma and the longitudes npon the observations at Yuma by the Coast and Geodetic Survey in 1892. The tables of geographical positions are given in Chapter IV of United States Report. The location of each station will be found upon the published topographical maps. The latitude and longitude piers of brick and cement were left standing in the east room of tlie adobe building which forms a part of the north wall of the old Government corral in Yuma. The brick pier at the azimuth station was left standing. B Tangent 10 is marked by a pine stake. EastBase, station and references five eighths-inch iron rods, X. 1..'553 m.. E. 1.038 m.. S. 0.(i72 m., W. 1.347 m. West base, station and references 2-inch by 4 inch pine stakes, N. 2.07S m., E. 1.951 m., S. 1.76(i m., W. 2.223 m. No. 9, station and references 2-inch by 4-inch pine stakes, N. 0.6(;o m., E. 1.512 m., S. 1.010 m., W. 1.913 m. No. 10, station and references five-eighths-inch iron i-ods, E. 2"^ N. 3.085 m., S. 27° E. 1.971 m., \V. 2° S. 2.172 m. (distances measured on slant). No. 11 was on (he sand hills west of the Colorado, and the station marks were doubtless blown away in a short time. MAGNETIC! OBSERVATIONS. The observations for magnetic declination at the first twelve astronomical stations were all taken with Coast and Geodetic Survey repeating theodolite No. 149. The horizontal circle, 20 cm. (8 inches) in diameter, is graduated in five minute spaces and is read to five seconds by two opposite verniers. On the top of the telescope was mounted a compass box containing a G-inch magnetic needle and carrying compass sights of the usual form. No iron or steel was used in tlie construction of this instrument or its tripod. Astronomicul station. Dat«8. Magnetic declination (K.«fN.) 1892 No. 1 Jtb 20 I'.h 22 M.ir 12 11 53 No. 2 Mir 23 26 28 29 A|,. 2 10 IC No. 3. A,,rl) 11 5(i No. 4 Vpi 30 Ma\ 2 i 12 00 No. 5 June 2 1 4 12 03 No. 8 June 27 U .-.4 No. 7 Tul\ 7 12 20 2- 12 14 No. s All^ lo Ih 1') 11 57 No. !) Si,I)t 2 17 12 23 No. 10 Oct 20 12 19 No.U ^o\ 12 15 12 06 No. 12 ])oc 12 n 1 12 25 UNITED STATES AND MEXICAN BOrNDARY. 113 CIL\JPTEK IV. The geodetic operations executed by the United States section of tlie commission were as follows: I. Tracing parallels 31° 47' and 31^ 20' bj' means of tangents to tlie prime vertical at the point of beginning and offsets from the same. II. Tracing the meridian section by simple alignment, its direction having been previously verified. III. Tracing the azimuth lines, either by straight lines connecting accepted existing old monuments or by offsets from auxiliary lines dittering as little as practicable from tliese lines. IV. Triangulation made in the vicinity of the initial monument on the liio (Grande to refer this monument to the United States astronomical observatory and to prominent public buildings in El Paso, Tex., and Giudad Juarez, Mexico. V. Triangulation made in the vicinity of Nogales, to refer Monument 127, at the west end of parallel 31° 20', to the United States astronomical observatory in Xogales, Ariz. VI. Triangulation made in the vicinity of Yuma, Ariz., to refer Monuments 204 and 207 to the United States astronomical observatory in Yuma. The geodetic constants conform to Clark's 1860 Spheroid. The principal constants which enter into the formuhv adopted are as follows: Miijor semiaxia = a = 6,378,206.4 meters. Minor seraiaxis = 6 =6,356,58.3.8 meters. a' — b- Eccentrioity = —.— = .- ^- 0.(K)6768658. a:b:: 294.98 : 293.98. Radius of sphere with volume of Clarlv's 186(i Spheroid =(>,370,9!»1 meters. Radius of sphere with surface of Clark's 1866 spheroid = 6„'>70,997 meters. Length of meridian quadrant = 10,001,887 meters. 1 meter = 3.2808693 feet = 39.3704316 inches. 1 kilometer = 0.6213768 statute mile. 1 foot = 0.30479727 meter. 1 statute mile = 1,609..3296 meters. TT = 3.14159265. Before entering into a description of the methods employed in tracing the different sections of the boundary line, it is necessary to explain M'hat is meant by a "straight line," since, as shown at the beginning of the chapter, every portion of the boundary line as marked was traced either by the aid of auxiliary straight lines or by straight lines joining consecutive old monuments. The theoretical straight line joining two points on the surface of the earth lies in the plane which passes through both points and the center of the earth, and if traced would mark the inter- section of this plane with the surface of the earth. Owing, however, to local deflections of the jilumb line, it is ])ractically impossible to trace this theoretical line, but a number of so called straight lines, differing but little from one another and from the theoretical line, can be traced, the particular line obtained in each case being dependent both upon the method employed and the locations of the instrument stations. For example: If two points, A and B, are visible from one another and from intermediate points, and if, as is almost invariably the case, local deflections of the plumb line exist at both A and B and also at intermediate points, a number of ditterent lines, apparently straight, may be run joining A and B, thus: (1) If the instrument remains at A and the foresight at B and inter- mediate points are "lined in," a certain line will be traced; (2) again, if the foresight at B remains flxed but the instrument is moved up successively to each intermediate point as established, a second and different line will be obtained; (3) if the backsight at A remains flxed and inter- mediate points are successively established by the method of reversals, the instrument in each case being moved up to the point last established, yet another line will be obtained; (4) if the 114 T-NlTi:i) STATES AND MEXK'AN BOUNDAKY. iutermcdiate points are located by the method of reversals, the iiistniiiieiit being moved up as in the last case and the backsight established at the next preceding point, a fonrth line will result; (5) if both foi-esight at B and backsight at A remain fixed, and intermediate points are established by "lining in" the instrument, a fifth line will be traced. Now, if exactly the same methods are followed, working in an opposite direction (B toward A), five additional lines will be obtained, and by a combination of the preceding methods a still greater number of lines will result, all differing slightly from one another and from the theoretical straight line sought. Computations having shown that for the distances to be encountered on this survey, and for ordinary local differences of deflection of the plumb line, lines accurately traced by any one of the preceding methods would be sufficiently accurate, all of them were used at one time or another, as found most convenient. In general, however, a combination of the first and second methods was employed as being quite expeditious, and dispensing with the necessity of a backsight. The instruments used in tracing straight lines were Fauth repeating theodolite No. 725, with 10-inch horizontal circle graduated to 5-minute spaces and read by two opposite verniers to 5 seconds, and Wiirdemann repeating theodolite No. 85 of the pillar pattern, with 8 inch horizontal circle. At the commencement of operations wooden targets about 3 feet scjuare, mounted on tripods, and similar to those described on page Mo of the report of the survey of the " Northern Boundary of the United States from the Lake of the Woods to the Summit of the llocky Mountains," were tried, but owing to the fact that during the greater part of the day they were seldom visible more than .'5 miles, and to the further fact that, due to the constant winds to which they oi)posed so large a surface, they were continually displaced, the use of these targets was soon abandoned and heliotropes were substituted for them with results entirely satisfactory. These heliotropes were rather crude affairs, with mirrors of 3 and 4 inches diameter, and were unprovided with any means for imparting a uniform slow motion to the mirrors. At first the mirrors were so mounted on their tripods as to admit of a lateral, sliding motion, but this arrange- ment was found to be of no practical advantage, and they were afterwards rigidly attached to the tripods. After the completion of the tracing of the meridian section of the boundary a reconnoitering telescope, with heliotrope attachment (but without any means for imparting slow motion to the mirrors), was obtained, and proved to be a valuable addition to these instruments. The heliotropes were plainly visible to the naked eye up to .'U) or 40 miles, and on rare occa sions up to 85 miles, at which last distance they could generally be seen through tlie telescope of the theodolite. Not only did the heliotropes ])rove valualde as targets, but they also afforded a ready means of communication between the observer and the heliotropers, sometimes by means of the Morse code and sometimes by a shorter special code. The advantage of being able to communicate freely with an isolated party 20 to 80 miles distant, in an unsettled region where supplies are scarce and roads bad, and where, as in one case, it took five days' hard travel by pack train to reach it, can scarcely be overestimated, and much anxiety is spared when it is known that such a party is well, and properly provided with water and provisions. In connection with heliotrope communication should be mentioned the experience of Mr. E. L. Ingram, assistant engineer, with the 80-mile sight on the California azimuth line between the sand dunes west of the Colorado Kiver and the summit of the Coast Bange, where the signals were hard to understand and easily mistaken when the light was poor. They failed repeatedly until he devised a rough method for imparting slow motion to the mirrors, after which signals were received by the front heliotroper, 80 miles distant, with absolute certainty. If the heliotrope nurror, as ordinarily mounted, is fastened in its bearings tightly enough to resist the action of the wind, it is impossible to impart to it a uniform slow motion, even when moved in the most delicate manner by the method generally employed — that of tapping it gently with a pencil — and on long sights, where the light is faint and the atmosphere in a state of vibration, these iri-egularities of motion are sometimes confused with the flashes of the signal code, and it UNITED STATES AND MEXICAN BOUNDARY. 115 would seem that for extensive use over long- distauces heliotropes provided with telescopic lines of sight aud with mirrors capable of a slow and uniform motion would amply repay in efiicieucy. their increased first cost. To avoid confusion, and in order that the original monuments already alluded to may be more readily located on the map, only tlie numbers placed upon them when repaired or rebuilt are given in the description which follows. PAUALi.Er, M IT . The successive steps in tracing the parallels were as follows: 1. Azimuth oUservations at the iuiti:il point of the tangent. 2. Tracing tlie tangent. 3. Observations attlio end of llio tangent to ileterrainc its liack-a/.iiiintli error. 4. Computing the oflsets. 5. Lociiting the monnnient sites. 1. Azimuth ol>.serration>i at the initial point of the tangent. — Tlio instruments and methods employed and the results obtained are described in Chapter III, Astronomy, and in the report of Mr. J. F. Hayford, assistant astronomer, and need not be repeated here. 2. Tracing the tangent. — The instruments and targets u.sed in tracing the tangents have already been described. The initial direction of the tangent was obtained by turning off an angle of 90^ from the meridian through the point of beginning and establishing a point on the tangent at as great a distance as practicable. The tangent was then prolonged by the method of reversals, the instrument being set up over the last point established and the back-sight being located at the most distant previously established point of the tangent visible from the instrument. The tele- scope was then transited over and a new point established as far as possible in advance. This operation was repeated four times with the telescope alternately direct and reversed, and the mean of the four points thus established was accepted as the true prolongation. Bach tangent was prolonged until it reached the meridian of the next succeeding astronomical station. When a point in advance had thus been established, a heliotrope was set up over it as a foresight aud intermediate points were generally " lined in," using range poles as targets, the instrument being moved forward from time to time as necessary, as the pole was seldom readily visible more than about 3 miles. On parallel 31"^ 47' distances along the tangents were measured both by chain and stadia, and the stations marking the tangents were located at a distance of 1 kilometer apart. These stations were generally marked by a L'-inch by 3-inch stake driven into the ground and projecting from 7 to 18 inches above the surface. Around the stake was piled a mouTid of stones to protect it from injury. A small witness stake was driven out of sight 1 meter south of the station stake, by means of which the latter could be replaced in case of removal. In establishing points in advance on the tangents by the method of reversals, the two points established with the telescope in the same position seldom dift'ered more than a few inches, even for distances as great as SO miles, while the other two points established with the telescope in a reversed position sometimes differed as much as 10 feet, due largely to the fact that the coUination error was very variable owing to the jolting received by the instrument during transportation over rough roads. Six tangents in all were traced on parallel 31° 47', which are fully described in tlie table in section 9, geodesy, of the Report of the Joint Commission. Tangents Nos. 1, 2, 3, and ."i of that table are main tangents. The other two are <;heck tangents. Owing to the great scarcity of water and the difficulty of getting supplies to the tangent party, tai.gent No. 1 was traced at all hours of the day, regardless of atmospheric conditions, and on account of the flat character of the country the average length of each prolongation was less than 3 miles. As a result of these and other unfavorable conditions the tangent rapidly deviated to the north, with a final back-azimuth error at the meridian of Monument No. 15 of 186.fi". Refore commencing the erection of monuments this tangent was retraced, for direction only, with a probable back-azimuth error of 1". In locating monuments offsets between Monuments Nos. IIG UNITED STATES AND MEXICAN BOUNDARY. 3 and -11 were referred to the original tangent and corrected to conforui to the new taugeut. Between Monuments Nos. U and l'> ol^sets were referred to tangent No. 13, and the original taugeut was uot used. 3. OhsenHitions at the end of the tdmjent to determine its i>ack-azimuth error. — The azimuth observations at the end of the tangent were identical with those at its initial point and served both to determine the back-azimuth of this taugeut and to give the initial direction to the new one. The ditterence between the observed and theoretical value of the back-azimuth is designated as the "back-azimuth error." and indicates the degree of accuracy with which the tangent was traced. Back-azimuth error of tangenU on parallel Sl^ 47' . 4. Computing the offsets.— From Appendix 7, Eeport for 1884 of the United States Coast aud Geodetic Survey, we have the following general formula for computing difference of latitude: -(/ L=K CO.S ;?.B+K3 Sin- Z.C + (dL)- D-7( K^ sin^ Z.E, in which K = distance in meters; L = latitude; Z = azimuth of line; R = radius of curvature; N = normal to the polar axis at the Station; B= ^, ^ ^ -; G= ^-^^^^-^,, R arc 1" 2 R.N arc 1" When Z = 90° the above fornmla becomes —d L=K- 0, in wliich —d L is expressed in seconds of arc. To obtain the offset in meters this must be multiplied l>y the value of 1" of :irc in meters for the latitude used. For parallel 31° 47', 1" of arc = .".O.SOO meters, and the workin.i;- formula for this parallel log d L=2 log K-7..U 402313. The offset obtained from this formula is from a theoretically accurately traced tangent to the parallel 31° 47' passing through the initial point of the tangent, and may properly be designated as the " theoretical offset." The identity of the original monuments having been established and their positions located, it became neces.sary to compute the offsets from the tangents, as traced, to a curved line joining consecutive accepted original monuments, which line should have as nearly as possible the same degree of curvature as parallel 31" 47', and would form the actual boundary line to be marked by monuments. The, offset from the tangent actually traced to the monument curve is composed of four parts: (rt) Tiie theoretical offset already described. {b) A correction for error in tracing the tangent. (c) A constant, measuring the distance of the initial point of the tangent north or south of one of the original monuments. (d) A proportional part of the distance by which a true geodetic parallel tlirougli one original monument passes north or south of the other original monument. This may be shown graphically in the following sketch (j). 117), in which tlie offset, K P, to the monument curve is a + h+c—d. The distribution of the back-azimuth and tangent errors was made in such a manner that they would harmonize, inasmuch as one is practically a direct function of the other. In some cases the tangent error was measured in the field, and in others it was computed in conformance with the distribution of the back-azimuth error. In all cases the known errors received ciarefnl UNITED STATES AXD MEXICAN BOUNDARY. 117 118 UNITED STATES AND MEXICAN BOUNDARY. consideration and were distributed in the simplest possible manner consistent with observed favts. (For further details relating to this subject see report of Mr. E. L. Ingram, assistant engineer, Appendix 1 of this chapter.) Probably the best check upon the method of distribution employed is given in tlie table of " Final distances between monuments on parallel 31^ 47','' in section 9 of the Repoit of the Joint Commission, where it will be seen that although the United States and Mexican tangents were totally different, and traced at different times, the average discrepancy in a nortli and south direction between their locations of the -iO new monument sites on this parallel was but 0.435 meter. 5. Locating the monument sites. — Tiie field maps and the profiles obtained from the line of levels carried along the tangents afforded the means of locating approximately beforehand the monument sites at such points that any completed monument would be visible from the two adjacent ones. Each approximate site was afterwards visited in the field when the monument party arrived in the vicinity in order to verify the indications of the field maps and profiles. The meridian in which the offset was to be measured was obtained by turning oft' from the tangent an angle dependent upon the theoretical azimuth at tlie point plus or minus tlie distributed azimuth error at the same point. In this meridian was measured the offset computed as already described. Precisely the same operations were executed by the Mexican section of the commission from their own tangent and their own measured distances, and the mean of the two points thus located was taken as the true location. THE MERIDIAN SECTION. The methods employed were substantially those used on parallel 31'J 47' except that chaining was abandoned; stations were placed at une(iual distances apart and at probable monument sites instead of at intervals of 1 kilometer, and the line actually traced was one joining the 3 original monuments which marke I the meridian. It was found that from a point on the summit of a hill 2 miles south of Monument 40, and in the same meridian, Monuments 4() and 4(i and a point on a hill one third of a mile north of Monument 53 were visible. From this last point, on which was afterwards established a heliotrope as a front sight. Monu- ment 53 was also visible. Observations showed that the .5 original monuments were in Ihe same straight line, and that this line was a true meridian. It was intended to locate the intermediate stations on the same line, but owing to the small size of the transit used a slight deviatiou occurred between Monuments 40 and 53 amounting to a maximum of 1 decimeter. The small offsets from this portion of the line as traced to the true meridian were computed and the necessary corrections made before monuments were erected. The azimuth observations at the initial point and the metliods employed in tracing the tangent were similar to those already described on parallel 31° 47' except that, as in the case of the meridian section, the tangent stations were placed at une:|ual intervals on prominent points along the tangent. The use of the chain in measuring distances was abandoned at the west end of parallel 31° 47' and never afterwards resumed. Eight tangents in all, numbered from S to 15 inclusive, were traced on parallel 31'^ 1!0', and are fully described in the table in section 9, geodesy, of the Keport of the Joint Commission. All of these tangents except Nos. 12 and 15, on which Fauth repeating theodolite No. 725 was used, were traced with Wiirdemann repeating theodolite No. 85, which had been used exclusively heretofore. UNITED STATES AND MEXICAN BOUNDARY. 119 Jlev kdometer of distance, and estimating his distance from the theodolite, the heliotroper readily com])uted the approximate offset to the desired line. This he then measured upon the ground and showed his heliotroiie from the new position. The observer again measured the angle between the heliotropes and communicated the result as before. The difference between the first and second micrometer readings, and the known length of the measured offset, enabled the heliotroper to determine his previously estimated distance from the instrument, and to compute quite accurately a new offset from the point last established. This process was repeated until the angle between the two heliotropes measured less than two micrometer divisions (2.5"), when the observations were completed by a measurement of this angle by 27 pointings, in sets of 3 alternately, with eyepiece micrometer on the two heliotropes. Using this measurement and the more accurate stadia distance afterwards determined by the topographical party, the small offset from the station as marked to the true line was computed and furnished to the monument party previous to the erection of monuments. Sometimes as many as seven intermediate points were established from a single instrument station; sometimes the instrument was moved up to every new station as established, and occa- sionally it was lined in between two fixed points. UNITED STATES AND MEXICAN BOUNDARY. 121 The time occupied in establishing au iutermediate station within 2.5" of the line, and theu measuring the final angle, varied from about thirty to sixty minutes. From Monument 175 to Monument 127 each original monument, except Monument 150, was visible from the preceding one, and the line was traced by placing a heliotrope over one monument and running toward it from the preceding one. Monument 150 was not visible from Monument 100, and the peak which intercepted the view, Cerro de la Lesna, had sides so nearly vertical and a crest so narrow and disintegrated that it was practically impossible to set up an instrument on it in order to " line in " a point on its summit. Accordingly, a strong geodetic connection was made around the south side of the peak, by means of which points on the line joining the two monuments were established on both its eastern and western base, as well as on its summit. (For details of this connection see report of Mr. John F. Hayford, assistant astronomer, Ajjpendix i of this chapter.) Between Monument 127 and the Colorado River the boundary line as finally marked by monuments is a broken line of 12 straight sections, changes of direction occurring at Monuments 129, 136, 137, 141, 140, 150, 100, 102, 108, 175, and 204. That actually traced by the line party was a broken line of 14 straight sections, which at no point, except at Monument 128, differed as much as a meter from the line afterwards marked by monuments. An old monument which stood 1.81 meters uorth of Monument 128 was connected by the line party with Monuments 127 and 129, but this monument was afterwards considered by the engi- neers in chief as unauthentic, and the boundary line finally adopted was the straight line joining Monuments 127 and 129. The inital direction of the line from Monument 204 eastward was obtained from the Yuma triaugulation. All angles in the broken line traced were measured by micrometer except that at Monument 175, which was too large for micrometer measurement and was measured by the theodolite used as a repeater. In the vicinity of Monument 127 this line was connected with a line of the Nogales triaugulation, and the accumulated errors of the azimuth observations at Yuma and JSTogales, the triangulatious at these places, and the measurement of 10 angles along the broken line traced was found to be but 0.7". To show more clearly the departure of the line as marked by monuments from the theoretical straight line joining Monuments 127 and 204, the offsets from tlie latter to the accepted original monuments were computed by Mr. John F. llayford, assistant astronomer. These offsets are all measured to the south and perpendicular to the theoretical line Offsets from titeorctival straight line joining Monuments 127 To Monuments Oflset. To Monumeut^ Offset. Meters. Meter: 127 U U 150 657.7 12S li I 100 974.9 136 J31 1 102 1023.8 137 1)0 4 1C8 1183.6 Ul 359 9 17d 1413.2 146 540 8 204 0.0 The computed angles between the different sections of the Sonora azimuth line, as marked by monuments, are given in the following table. The angle is the deviation to north or south of the next section from the preceding section i)roduced. AtMocu,..e.U- Deviation. Direction of deviation. At Monuments Deviation. Direction of deviation. 3 28 13 1 56 3 8 S. N. S. N. N. S. 160 29 34 1 46 55 2 51 46 N. S. S. N. S. 162 146 204 i5o::::;;::;::::::::::;. S. Doc. 247- 122 UNITED STATES AND MEXICAN BOUNDARY. Ill establishing the uiouumeut sites the very small offsets from the line as traced to that which was to be marked had been previonsly computed by the assistant astronomer who traced the line, and were measured at right angles to this line. The average discrepancy in a uorth-and-south direction between the United States and Mexican locations of the 67 new monument sites on the Souora azimuth line was 0.30S meter. THE CALIFOKNIA AZIMUTH LINE. As uo two of the six original monuments which marked tliis line were iutervisible, it was impossible to follow the method employed in tracing the Sonora azimuth lino. Accordingly, the line actually traced was a broken line of five straight sections, which at no jjoint diverged more than G3 meters from the line finally marked by monuments, itself a broken line of five straight sections witli changes of direction at Monuments 220, 221, 252, and the monument at Tijuana, destroyed by flood in January, 1895, and replaced by the present JNIonument 255, situated a little over a kilometer further east. The initial direction of the first section traced was a prolongation in two sights, to the summit of the Coast Range, of the line joining "Boundary Post" (Monument VII of the original survey, which located the junction of the Gila and Colorado rivers) and Monument 207. The second section was purposely deviated to the south, and prolonged in a single sight to Mount Tecate, with the object of drawing the Hue traced closer to the boundary line and thus reducing the length of the offsets, a result which was not attained, owing to the eftects of local deflections of theplumbliue. For the purpose of back-azimuth and latitude computations this last section was produced to the meridian of Monument 258, passing 140.07 meters south of the monument. The third section connected tin; station on Mount Tecate directly with Monument 252; the fourth section was traced between Monument 252 aud the monument at Tijuana, afterwards destroyed by flood, and the fifth section connected this last monument and Monument 258 on the Pacific. Intermediate points were generally established with range poles by running toward a heliotrope previously located in advance, the instrument being moved forward as found most convenient. As the tlieodolite used by Mr. E. L. Ingram, the assistant engineer who traced this line, had no micrometer, it was impossible to adopt the method employed on the Sonora azimuth line in establishing intermediate points, and was diflftcult to estimate correctly the distance that the intermediate targctman should move to come upon the line. Flashes of five seconds' duration indicated a movement to the north and of one second a movement to the south, the number of flashes giving an approximate idea of the distance. Computimj the offsets. — The formulie used in computing the ofisets from the broken line traced to that to be marked by monuments are given in the report of Mr. B. L. Ingram, assistant engineer. Appendix I of this chapter, and are based on the original stadia measurements, reduced to sea level, as the final adjusted latitudes and longitudes, by the use of which were obtained the dis- tances in column 7 of the table of "Final distances between monuments on the California azimuth line" (section 9, geodesy, of the report of the Joint Commission), and the corrections due to remeasurements were not then available. From the data then at hand the computed length of the straight line joining Monuments 207 and 258 was 225,586.2 meters, and the corresponding back-azinuitli error 23.8", Avhich, before computing the offsets, was eipially distributed at each of the three main heliotroi)e stations. These were located on the sand dunes west of the Colorado Eiver, on the summit of the Coast Range, and on Mount Tecate, respectively. This back-azimuth error represents the accumulated errors due to the azimuth observations at Yuma and Monument 258, the errors in triangulation at the former place, those in tracing the different sections of the broken line, aud in measuring the various angles along this line and in the vicinity of Monument 258. Later computations based on the final adjusted latitudes and longitudes give the distance between Monuments 207 ami 258 as 225,570.2 meters, which would reduce the back-azimuth error of 23.8" by but a fractional part of a second. If, as indicated by the close agreement between the United States and Mexican stadia measurements of this distance, there is a considerable "station error" in longitude between Monuments 207 and 258, and the back-azimuth error be computed, using the mean of the United States aud Mexican stadia measurements, it will be found to be less than sixteen seconds. UNITED STATES AND MEXICAN liOUNDAKY. 123 The averaj^e iliscrepaiicy, measured in a north-and-soutli direction, between the United States and Mexican locations of the 48 new monument sites on the California azimuth line was 0.467 ■ from the Colorado River toward the Pacific Ocean, the following appreciable computed changes of direction occur in the line as finally marked by boundary monuments, the angle given in the table being the deviation to north or south of the next section from the preceding section produced. AtMouuoaen^ Deviation. Direction of deviation. 220 .. S. 221 47 S. 252 2 a N. 255 42 .. In spite of these deviations, however, the most distant monument — No. 220 — from the theoret- ical straight line joining Monuments 207 and 258 is situated less than 70 meters north of this line. GENERAL KEMAUKS ON TANGENT AND LINE WOUK. Mr. John F. Hayfoid, assistant astronomer, personally traced the Souora azimuth line and also tangents 12 and 15 of parallel 31'^ 20'. All other tangent and line work was executed person- ally by Mr. E. L. Ingram, assistant engineer. The successive tangents and straight lines were connected with one another and with the astronomical stations, thus forming a geodetic chain from the Rio ftrande to the Pacific, by means of which could be computed the station error at the various stations — /. e., the diflference between the observed latitude of the station and that transferred, geodetically, from the preceding station, a difterence due to local deflections of the plumb line. These station errors have been computed and are given in section 13 of the Report of the Joint Commission, "Construction of the maps of the boundary." All distances measured along the tangents and auxiliary lines, as well as all bases employed in triangulation, were reduced to mean sea level of Sau Diego Bay, California, by the formula d = *', in which r = the normal corresponding to the base, b, at the level of the .sea: >• + « = that »• referred to the level of the measured base, B; 3 = the desired correction. Owing to the intense heat, so great was the personal discomfort suffered by those engaged in work on the desert, aiid so difficult and expensive was it to supply the working parties with pro visions, forage, and water, that it was deemed expedient to hasten work with but little regard for conditions most favorable for observations, as it was believed that sufficient accuracy could be obtained and a great saving in expense eftected. As an extreme instance of the difficulties under which work was prosecuted, it may be men- tioned that at one point on the Tule Desert all of the water for men and animals was carried 102 miles — 30 miles in tank cars, from Yuma to Adonde Siding on the Southern Pacific Railway, and 72 miles in water wagons, from that point to the camp on the desert. As much of the observing, both on the Sonora and California azimuth lines, was done under conditions api^arently so unfavorable, it may be interesting to give, in addition to the back-azimuth errors and discrepancies between United States and Mexican locations of monument sites already mentioned, the results of experiments made by Mr. John F. Hayford, assistant astronomer, on the Sonora azinmth line, as to the accuiacy of pointings upon the heliotropes and the remarkable variations in the apparent size of their lights, which variation was fully confirmed in every respect by observations made by Mr. E. L. Ingram, assistant engineer, on the California azimuth line. From May S to September 15, 1.893, a record was kept during observations, of the temperature, the appearance of the heliotropes, and the apparent diameter of the heliotrope light as measured by the micrometer. The shade temperatures during observatious varied from 77° F. to 118'^ F., averaging about 100- F. 124 UNITED STATES AND MEXICAN BOUNDARY. The apparent diameter of tbe heliotrope light iu divisions of the micrometer, 1.24" each, varied from 5 to 104 divisions; the first occurring in the morning or on a cloudy day, and the last, in a single case, a little before noon of a very hot July day on a sight of 2 kilometers, passing within 3 meters of almost bare sand. The average apparent diaineter of the light from all measurements was 25 divisions =31". The diameter of the principal mirror of one hcliotroi)e was 10 centimeters, that of the other was 7.5 centimeters. Computations based upon the distance to the heliotrope light and its apparent diameter, as measured by the micrometer, showed that the mirror itself was visible upon very rare occasions, if ever, but that the apparent diameter of the light was many times that of the heliotrope mirror; for example, iu one instance the measured apparent diameter of the light of the 10-centimeter mirror corresponded to that of a target ll.t meters in diameter placed where the heliotrope was located, 43 kilometers distant. Although varying greatly at different times, it may be stated in general terms that the meas- ui'ed angle, subtended by the apparent diameter of the light, was independent of its distance from the instrument; for example, at 2,000 meters a mean of 3 different measurements gave the apparent diameter of the light of the 10-centimeter mirror as 19 micrometer divisions, while at a mean distance of 40,500 meters the mean of 37 different measurements M-as 20 divisions. Not only were there abnormal variations in the apparent size of the light, but also in its form. When a steady breeze was blowing across the line of sight the disk of light appeared flattened on the windward side and blown out on the leeward side, very much as would be the flame of a candle. When great distortion of the size of the light occurred it frequently appeared blurred, and always with one part of the blur brighter than the rest. Generally the bright region was iu the center, but sometimes it was unsymmetrically situated with reference to the outline of the light. "In those cases the brightest region was always to windward of the center of the blur and the leeward part of the outline vibrated more violently than the windward side." (For further details of these investigations see report of Mr. John F. Hayford, assistant astronomer, Api)endix 4 of this chapter.) In all cases pointings were made in sets of 3, upon the center of the brightest part of the light. In spite of the apparent distortion of the light as regards size and form, tlie accuracy of the pointings was not greatly affected thereby, as is shown by the following table, in wliich zAs is the mean of the ditt'erences between each of the 3 ijointings of the set and the mean of the 3. Heliotrope with ]0e utimeter Heliotrope with 7.5centimeter Diameter, divisions. ., Number of obacr- vations. Diameter, divisions. A3 Number ofohser- U-15 10-28 29-67 U.82 1.05 1.43 42 46 38- 1 0-20 I 21-34 35-104 0.78 0.88 1.61 77 71 48 The maximum value of ^3 in the above table corresponds to ±2.7" for the probable error of a single pointing, and justifies, so far as accidental errors are concerned, observations made under such apparently unfavorable conditions. Observations made iu the Tule Mountains to determine whether there was any apparent dis- placement of the light when the heliotrope was neglected, and whether the apparent position of the light coincided with the actual position of the heliotrope mirror, showed that at 4 kilometers distant the heliotrope light seemed to be 0.19" south of a pole with which it had been accurately ranged iu line, but did not prove "'conclusively that there was any apparent change in the position of the light when the mirrors were neglected" from fifteen to twenty-five minutes at a time. "The accidental errors of pointing seemed to be slightly greater when the mirrors were first adjusted than later when the light had become less bright and apparently smaller." Observations made at a distance of 5,S00 meters to ascertain the effect of reducing the 7.5- centimeter mirror to a diameter of 2.5 centimeters showed that the apparent diameter of the full- sized light was 25 divisions, while that of the reduced light was 23 divisions, and that the latter appeared almost as bright as the former. "The accidental errors were as great with the reduced as with the full light." UNITED STATES AND MEXICAN BOUNDARY. 125 At Momimeut l(>s special investigation was made "to (leterinlni' wlietlier tbere was a systematic ditt'erence between forenoon and afternoon oliseivations, and wlietlier there was any systematic error due to tlie position of the back glass," The resnlt showed tiiat the heliotrope a[)peared to be 0.74" fartiier south in the forenoon than in the afternoon, and that the i)osition of the back glass north or sonth of the line did not aflect the result. To detect constant or systematic errors a line 25,.S00 meters in length was located, both by lining in points ahead and by lining in the instrument between two known points. "The greatest difference between the two locations at any of the 10 intermediate stations was 32 centimeters and the average difference 17 centimeters. With one exception, all stations as located by the second method were tarther south than by the first method." A few experiments made by Mr. E. L. Ingram, assistant engineer, seemed to indicate that an eastandwest line traced toward the west, with heliotropes a.^ targets, had a tendency to turn toward the north, a statement which is partially confirmed by the fact that 9 out of 11 lines checked had positive backajciinuth errors, and consequently deviated toward the north. Another peculiar phase of heliotrope action was often observed, i. e., the much greater actual dispersion of the exterior rays of the eoiie of retlected rays than should have been the case theoretically. In conclusion it may be stated that all experiments and invesligations confirmed in the most satisfactory manner the reliability of heliotropes as targets under the apparently unfavorable conditions under which they were employed on this survey. TI5IANGULATION IN VICINITY OF EL PASO. A base was measured on the railroad near Astronomical Station No. 1 and a triangulation laid out from this base connecting Astronomical Station No. 1 with Monuments 1, 2, and 3, and the magnetic station near No. 1, and with the United States longitude station at El Paso; also with the public buildings in El Paso and Juarez. The following is a list of the geographical positions of the objects determined, and a sketch of the triangulation is given at the end of this chapter. (!eoi)raphicul positions of poitits in the ity of Kl Paso, Tex. Stations. Latitude. LongituJi-. Azimuth. B.-ick azimuth. To stations. Distance. A.stronomical, No. 1 31 46 .59.40 31 47 15.53 31 46 57.68 106 31 25.07 106 31 24.81 106 31 23.98 100 31 39 03 !I0 00 16.4 180 58 23.2 178 30 40.1 36 58 21.1 357 44 20.5 05 24 48.6 W 29 24.1 86 13 20.5 313 49 15.4 97 37 00.9 92 44 18.0 91 09 23.1 102 23 14.2 270 00 09.1 58 23.4 Monument Xo. 1 ..... 305.4 Azimuthmarli Monument No. 1 South base 1,805.8 621.7 550 035 216 58 13.6 177 44 20.9 245 24 26.9 244 29 02.0 266 12 42.3 133 49 40.0 277 36 5:1.0 272 43 55.9 271 09 00.6 282 22 35.6 South base Monument No. 2 1,193.6 Monument Xo.l MoDumentNo.2 A * IJ 1, 707. 399.1 1, 108. 4 1,126.1 1, 975. Monimient No 1 31 46 59 40 203 50 38.6 270 23 45 2 83 51 47.5 nn 9.5 in i 3,460.4 4,243.8 2, 425. 9 5, 766. 1 5,403.5 6,929.1 1 • A A 31 46. 58.42 I ;; - 31 45 29.79 31 45 27.64 31 44 15.90 106 .■12 06.78 106 32 37 31 285 39 37.1 105 40 23.8 298 59 29.1 119 01 10.0 300 19 53.4 120 21 26.7 316 14 26.2 136 16 02.0 1 c B Courthouse Feileral building CathedralJuarez 3,451.2 3,117.7 4,995.4 Federal building 106 29 9.57 106 23 55.13 106 29 4.73 311 42 46.5 ; 131 43, 33.1 330 33-25.7 150 34 14.8 Federal building Cathedral Juarez Cathedral Juarez : 1 126 UMTED STATES AND MEXICAN BOUNDARY. TRIANdULATION AT SAN PKDRO RIVER. A iiioimmeut of dressed stone was found on the east bank of the San Pedro Eiver, and the astronomical observations of the United States section were made near the nionumeut, at Astro- nomical Station No. 10. Afterwards ajiother monumeMt, consisting only of a pile of loose stones, was found on the west bank of the river and was recognized as the one erected by Emory. It was evident that tiie monument found on the east bank of the river was the one erected by Salazar, who did not find the one erected by Emory on the west bank. By an agreement of the joint commission (see pp. 37 and 38, Emory's report), the one erected by Emory on the west bank was to be recognized as the one marking the boundary. A triangulatiou connecting these monuments was made by the United States section by means of a measured base line and a (juadrilateial cofluecting Astronomical Station No. 10, near Salazar's monument, with Station A on tangent line near Emory's monument. The difference of latitude between these stations was found to he -f 30.08", and between Sala- zar's monument and that of I'hnory + 20.07", the latitude of Sal;i/,ar's nionniiient being 31^ 19' 35" and Monument 20 of Emory being 31° 20' 4.67". As the observations of the Mexican section were made directly at the monument of Emory, theii' result for its latitude (No. 08, new) of 31° 20' 3.02" ± 175" was accepted in 1895 as tlie true latitude of Monument 98; the difference in station error in latitude accounting for the difference of the two results, = 1.65". TRIANGULATION AT NOGALES. A base line, 724.96 meters long, was carefully measured on the railroad at Nogales, Mexico, and a triangulatiou made connecting the United States survey huigitude .station at Nogales, Ariz., with the azimuth station. Monument 122, and various buildings in Nogales on both sides of the boundary line. This station was also occupieil by both United States and Mexican sections tor latitude observations. This triangulatiou transfers the latitude and longitude of the astronomical station at Nogales, Ariz., to Monument 127 at the intersection of the parallel of 31o 20' with the one hundred and eleventh meridian of longitude, as determined by Emory. Points on the tangent through the azinuith station at Nogales, Ariz., were also determined, giving the lengths of portions of tlie tangent independent of the stadia measurements. A sketch of the triangulatiou will be found at the end of this chapter, and a list of geographical positions follows: raphical jiositions of points ill/ nf Xogales, .Iriz. Azimuth. , Back-azimuth. Astronomical static Azimuth station... No.l N0.4 N0.2 N0.3 South base North base 31 20 U4. 31 20 00. 31 19 .'il. 31 18 .'•.9. 82 110 f>5 31 26.55 110 31 19 27.41 31 19 50.79 24.77 .17.14 34.07 01.45 41.24 I 47.81 147 13 47.2 126 03 289 36 188 21 86 15 85 47 161 46 327 13 45.5 306 02 34.2 246 50 20.7 266 14 47.7 341 45 50. 7 210 52 43. ( No.l.. N0.2.. No. 1 . . Sonth No. 2.. UNITED STATES AND MEXICAN BOUNDARY. Geographical positions of points in vacinily of Noijalea, Ari:. — C'oi 127 Xo.5 No.6 No.7 No.8 B Monument XIX* Comer Monument 127 Levys store (flag poJe) Montezuma Hotel («:!•; pole) - Mexican , (Hag Flag C. FlagD FlagE. FlagF. FUgG. FlagH Flag I. FlagK FlagM :il 20 11.52 31 21 40. 55 31 la .■.;.. 2C j 31 20 00.33 31 20 00. 33 31 20 00.32 31 20 00.31 31 20 00.30 31 20 00.29 31 20 00.26 31 20 00.22 274 43 15. 2 290 19 08.0 183 52 54.3 247 18 36.3 286 09 23.9 301 41 11.5 163 40 16.6 \ 283 30 08.8 165 .54 15.8 335 31 47.4 110 07 10.9 160 U 24.1 272 43 41.5 65 07 07.' 63 35 21.3 285 34 313 47 19.9 94 45 08. 6 j No. 3. , 110 21 05.1 ! No. 4. 3 52 58.3 ! No. 5. 67 20 33.7 No. 3. 106 12 29.9 121 44 13.4 110 56 43.15 58 22 06.6 73 37 24.6 233 54 47.8 110 57 10.03 111 00 30 69 111 04 26 00 No. 5 No. 6. 345 54 01.1 No.7. 155 31 54. 3 310 14 9K] 245 06 55.7 105 34 35.7 3,911.8 8,381.6 3, 075. 5 847.1 B 395.7 No.7 1 3,314.2 Azimuth station 258. 3 No.l [ 058.9 ....do ' 725.0 Azimuth station 214.3 Astronomical- 3, 526. U 4,470.4 5, 228. 6, 501. 2 8, 289. 2 12, 722. 2 TKIANCTTLATION IN VICINITY f)F YUMA, ARIZ. A base 2,203 meters long was measured on the level mesa east of the town of Yuma, aud an extensive system of triaiigulation made connecting the astronomical station in the corral of the TJnited States Quartermaster's Department, occupied by the Coast and Geodetic Survey for longi- tude, and by both the United States and Mexican sections for latitude, with the azimuth station of the United States section, with Monuments No. 207, on the west side of the Colorado River, and No. 205, on the east side of the same river 20 miles below the junction of the Gila aud Colo- rado. It was necessary to elevate the theodolite at Monument 205 about 25 feet by means of a tripod and scaffold to see the azimuth station. Station No. XXXVII of Tangent A, on the west ridge of the Tiimjas Mountains, was deter- mined, thus measuring by triaiigulation the distance of this station from Monument 204, giving a valuable check on the same distance as measured by stadia. 128 UNITED STATES AND MEXICAN BOUNDARY. Geogra2>hical poailioii) of points in vicinit>) of Yuma, Ariz. Latitude station Azimuth station Eaat base Nn.9 No. 10 Pilot Kiiol> No. II Monument 204 Station XXXVII, line A, on Tinaja.'i Mts. B Uountlary post Indian scliool (Hag jiole) Penitentiary (jiolu 1) P.-nilentiary (pole 2) ' FlagE Monnment 207 FlagF .'.. rlagG 53.83 23.38 ' 34.82 3.'-.. 40 01. 33 01. 8C 114 30 114 37 114 38 114 35 114 44 114 49 114 46 114 02 114 37 114 36 114 37 114 36 114 36 114 44 178 32 01.12 224 24 37.4 182 34 51.2 207 09 59.1 54. 91 265 59 48. 45 265 238 59 32.5 36 15.6 55 52.2 45 05.8 49 32.5 5B 35.2 22 39.2 41 55.1 05 02.4 46 00.9 36 38.9 46 00.8 39 42.8 39 55.7 29 10. 29 14.3 21 36.8 28 28.8 27 36.7 09 58.8 25 30.5 13 27.3 332 63 22.2 2 34 55.8 27 10 49.0 I 271 18 46,6 273 45 26. 169 58 4G.9 190 22 33.3 181 41 53.7 270 00 51.1 189 4r, 54.8 247 36 28.9 189 45 54. G 272 35 26.7 322 39 30. 1 85 32 50.3 265 29 10.0 28 21 5G.9 85 32 51.7 85 32 50.3 Latitude station . Azimuth mark-.. Azimuth station . Azimuth station . No.ll No. 10 No.lO Monument 204... Azimuth .station. Pilot Knob East base Azimuth station. Pilot Knob Azimuth station. Azinuitli station. Pilot Knob 1, 858. 1, 910. 9 4, 987. 3 5,275.6 4, 166. 4 6, 949. 12, 253. 13,578.9 9, 002. 22, 739. 2 23, 330. 5 25, 844. 4 06, 963. 73, 095. 5 1,515.0 11,871.3 3, 243. 7 1, 565. 9 2, 279. 2 12, 103. 5 1,728.0 523. 8 1,748.0 12, 345. 8 2,035.2 12, 852. G 15,154.4 5, 190. 21,255.9 2, 717. 3 Appendix No. 1. Report of Mr. E. L. Ingram, Assintant Engineer. San Diego, Cal., Ocfohrr 37, 1S9J. Followiug are the final reports oii tangent and line work intrusted to my care during the progress of the iireseut survey : 1. Report of tangent work, par.allel 31 47' N. 2. Report of line work, meridian line. ;{. Report of tangent work, parallel 31^^ 20' N. •1. Report of line work, azimutli line, Colorailo River to Pacil'io. 5. General report, common to all lines. 1. Report of tam/ent work, parallel 31° 47' J\'.— Work in my charge: Parallel ^iio 47' ^as located by the taugent (to the prime vertical) and offset method. Tlie duty assigned to me was to locate and mark in the Held such tangents as were necessary for this pui'ijose; to measure these tangents by chaining; to locate existing monuments with reference to tangents, and to make such other measurements and computations as were necessary and appropriate to the work in hand. Size of camp : The camp was made up of my own party proiter, together with several members of the topographical party, and the necessary help. The number of men varied more or less, but UNITED STATES AND MEXICAN BOUNDARY. 129 was about as follows: Tangent party — myself in charge — 1 recorder, 2 cliaiiunen, 4 targetmen; level party— 1 levelnian, 2 rodinen; stadia party—l transitniaii, 2 nxlnieu; help— 1 cook, 3 teamsters. Transportation: This was also very variable, but was about as follows: One baggage wagon with 4 mules, 1 water-tank wagon with (J mules, 1 spring wagon with 2 mules, 1 pack mule, 1 saddle horse. Supplies: These were furnished by the (piarterniaster, usually without the help of the camp transportation. Stations: Line stations were driven at each whole kilometer along each tangent, counting from its initial point, in addition to the main stations at the ends of the successive i)rolongatious. Eerunning of tangent No. 1: According to instructions, tangent No. 1 wa.s run at all hours of the day over a bui-ning mesa, regardless of all atmospheric conditions, in order to make ((uick time over a bad stretch of desert. In addition to this the average length of each prolongation was less than 3 miles, owing to the rolling nature of the country traversed. As a consequence of these and other unfavorable conditions tangent No. 1 deviated rai)idly to the north, with a final azimuth error of 180.0" at the meridian of Astronomical Station No. 2. Before commencing monument work I reran this tangent, for direction only, with a probable backazinuith error of 1", as well as it could be determined. In the actual location of momiments everything was referred to the original tangent, based on corrections derived from the new tangent. Between new Monu- ments Nos. 11 and 15 tangent No. 2 was used iu place of No. 1. Check tangents: Tangents Nos. 1,2, 3, and 5 are the main tangents. New No. 1 and No. 3a and No. 4 are check tangents, exerting their influence in the final location of the monument curve. Dates: The work iu my charge commenced February 12, 1892, and ended April 23, 1892. 2. Report of meridian line. — Work iu my charge: Practically the same, except that a meridian line through the existing monuments was located in place of a series of tangents; chaining was abandoned, and stations were placed at probable monument sites iu place of kilometer points; slightly reducing the size of the ])arty, the size of camp and amount of transportation remaining about as before. Dates: Meridian work was commenced April 29, 1892, and ended May 23, 1892. Method of running line: This line was run practically as a single sight. A hill 2 miles south of and seeing Monument 40 and a hill one third of a mile north of and seeing Monument 53 were found to be intervisible, and Monument 40 was found to be visible from the northern hill. Obser- vations at the dilfereut points of view proved the three monuments to be truly in line with each other and on a true meridian. It was iutended that the intermediate points located should also be on this line, but owing to the small transit used a deviation (1 decimeter) occurred in the lower part of the line and had to be* corrected by offsets when the new mouuments were located. At the upper corner a true meridian was established by the astronomical party, and the monument line was found to coincide therewith. At the lower corner it became necessary to use the Wiirde- mann theodolite to connect with tlie azimuth station, making the result unreliable to at least 5". The actual result obtained, if correct, would indicate a deviation of 3.4" to the east in running northward. 3. Rei)ort of tangent irorl;, parallel 31^ 20' K. — Work iu my charge: The duties assigned to me on this parallel remained practically the .same as before, with the addition of a small amount of topography iu the vicinity of Nogales, Ariz. During my absence on monument work (August 15-November 5, 1892) one tangent (No. 12) was run entirely by J. F. Hayford, assistant astron omer. Mr. Hayford also ran tangent No. 15 while I was engaged on topographical work. Camp and transportation : The size of the camp and amount of transportation was extremely variable, and were further modified by the topographical party, which was sometimes with ray camp and sometimes detached. Supplies: These continued to come through the quartermaster, depending partially on the camp transportation for their delivery. Dates: Tangent work, May 2G, 1892, to August 15, 1892, November 5, 1892, to December 0, 1892; absent on monument work, August 15, 1892, to November 5, 1892; engaged on topograpical work, December 7, 1892, to Jauuary 9, 189.3. 130 TINITl'.n STATES AND MEXICAN BOUNDARY. 4. Reporto/liiie irorh; OH azimuth line, Colorado Biver to Pacific, — Work iu my charge: All the work of this part of the survey, iucliuling liue, level, and topographical work. This, of course, does not iuclude the astronomical observatious for azimuth, made at each end of the line by J. F. Hayford, assistant astronomer, nor the triangulation from Yuma to Monument 207, which was also iu charge of Mr. Hayford. Size of camp: The camp varied in size with the character of the country traversed, but for the greater part of the time was about as follows: Myself, in charge, 2 transitnien, 1 levelman, 10 rodmen, 2 packers, 1 guide, 4 teamsters, 1 cook, 1 cook's helper. Transportation : Variable, but about as follows for the bulk of the time : Two baggage wagons with 4 mules each, 1 water-tank wagon with 6 mules, 1 spring wagon with 2 mules, pack mules, 2 saddle horses. Supplies: Up to May 10, 1893, all supplies were obtained from the quartermaster. From this date to September 20, 1893 (breaking up of camp), all supplies were purchased directly by myself as needed from time to time, and hauled by the camp transportation. Level and topographical work: The methods established by J. L. Van Ornum, assistant engineer, were adhered to in this part of the work. Line work : A broken line was run from the " Boundary post" in Yuma to the initial monument on the Pacific Coast. The line as actually marked in tlie Held is best seen from the sketch given in the monument report, but may be described as follows: Boundary post to Station 3 I (Coast Range) = prolongation of direction of liue from boundary post to Monument 207. Station 3 I — 1 L (Mount Tecate) deviates S' 52" to south from previous line. Station 4 L — Monument 252 runs direct between these points. Monument 252 — old Monument II runs direct between these points. Old Monument II — Monument 258 runs direct between these points. Deviation at Station 4 L = 16' 12,3" north. Deviation at Monument 252 — 8' 22.9" south. Deviation at old Monument II = 0' 38.2" north. The angles here given are computed values, and subject to coirection for errors in distances and back-azimuth error. The direction Station 3 I — i L was also prolonged to the meridian of Monument 258 (passing 140.07 meters south) for the purpose of back-azimuth and latitude work, and furnished the basis for computing the angles above given, which could not be directly measured as easily with equal accuracy. Tlie object of the "deviation at Station 3 I was to draw the located line closer to the actual monument line, but owing to the large station error between boundary post and Monument 258 this result was not achieved. The main heliotrope stations, or points from which the successive prolongations were made, are Station K, Station 3 I, and Station 4 L, and an equal distribution of back-azimuth error ( + 23.8") at these points is probably the best that can be done. Dates: Line work commenced January 14, 1893, and ended September 20, 1893, when the camp was disbanded and I was ordered to San Diego for office work. 5. General report. — The following notes and remarks, applying to all the tangent and line work, are here grouped together to avoid unnecessary repetition. All measurements are metric. All lines and tangents were run with Wiirdemaun theodolite No. 85, which is an Sinch repeater of the pillar pattern. In considering the results obtained it is but fair to remember that this instrument is extremely old, both in design and service, and capable of any use at all only with the greatest care. Fortunately it was possessed of a telescope of most unusual excellence. In the early part of the work the lines were extended by sighting on wooden targets about 3 feet square, mounted with a sliding motion on wooden tripods. These targets were painted black and white, and various designs were experimented with without success, and fiually the targets were given up entirely iu favor of heliotropes. As far as visible (about 3 miles) a common range pole was capable of far more accurate alignment than any of the targets. Beyond 3 miles, in spite of their size, the targets were as hard to distinguish as a range pole. A similar experience occurred UNITED STATES AND MEXICAN ROUNDARY. 131 later in the work in a slightly ■ ru 11 MonumentNo.il... Monument No. !.">.. . stronomical No. 2. TANGENT NO. 2. Zero. 19, 970. 39 19, 973. 80 22.91 4.14 .00 I TANGENT NO. Monument No 15 —3.41 Zero. 1,672.65 21, 470. 77 34,658.32 34,664.01 4.14 Zero. *0.0 to. 00 31 47 0. 21 0.0 0.00 Heliotrode 1 A 0.0 +23.4 0.00 27.05 68.40 60.84 2.25 A.stronornicalXo.3 3146 58.00 + 34.8 4.48 4.48 +34.8 * Assamed coustant between given points. \ In direct ratio between given points 136 UNITED STATES AND MEXICAN BOUNDARY. Tanncnl data — Contiuued. TANGENT NO. 5. Station. Offset N. Latitude. Back-azimuth error. Tangent error. Name. Number. Measured. Assumed.* Measured. N. Assumed. N.f Zero. 5.69 20,463.36 21,611.00 44,«5.U 44,423.78 Zero. 2.44 22.79 25.20 98.97 63.11 31 46 58. 00 0.0 0.00 0.0 + 1.6 + 1-7 + 3.4 0.00 0.078 0.086 0.306 0.366 Monument No 3' Monument \o. ■ 3146 58.55 + 3.4 •Indirect ratio. t As square uf distance. MONUMENT CURVE. The diagram i.s intended to indicate the geometrical conditions governing the location of the mouumeiit curve joining any two consecutive existing (old) monuments, and is almost self-explana- tory. The diagram, as will be seen, shows different conditions, all of which would not exist in any one case. The two tangents shown correspond to the two cases of error by which a tangent may be affected. The two monument curves represent two cases, depending on which terminal monument is farthest north. The computed ottset from the tangent as run to the true parallel through one monument is increased or decreased by the distance between the monument curve and parallel at the given point, and the distance between the parallel and monument curve is assumed to vary in direct ratio as distance from monument at intersection of the curves. Theoretical offset formuht, i)arallel 31° 47'. UNITED STATES AND MEXICAN BOUNDARY. 137 The oflset from taugciit as luii to luouuuieut curve at auy givcu point is made uj) of four parts, as follows: 1. TLeoretical oflset from a true taugeut to a true parallel tlirougli initial i)oiut of tangent. 2. A correction for tangent error. 3. A coustaut of translation corresi)ondiug to true parallel tlirougb oue monument. 4. A propoitioual part of tbe amount by wbicU a true parallel tbrougb one monument passes nortb or soutb of tbe otber monument. Tbe following table is formed from tbe data contained elscwbere in tbis report: Xa^.ent 0fl80t (by theoretical lurmula-). 1 Theoretical— tangent error + 1.12 — proji. part 28.45 2 Theoretical (no tangent error) + 4.14 — jirop. part .59 3 Theoretical— tangent error +4.14 + prop, part 2.79 3 Theoretical - tangent error + 6.93 + prop, part .U8 5 Theoretical — tangent error + 2.44 + prop, part .11 5 Theoretical — tangent error + 2.63 + prop, part .98 In these formubv- Log. theoret. = 2 log. sta. — 7.3140232, except for tiingunt 2, wh. sta. is meant distauoe from the initial jioiut of the taugont. Tang, error (Men. 3 to 15) ^interpolate as directed in tangent data. Taug. error (Mon. 15 to 21) = zero to sta. li)72.()5 and then log.^' [log. ( Tang, error (Mon. 21 to 26) = log.-' [log. (sta. —8134.68) — 3.7728459J. Tang, error (Mon. 26 to 40) = log.-' [2 log. sta. — 9.7315917 J. Proportional part 28.45 =log.-' [log. (sta. —4262.76) — 3.2849425]. = log.-' [log. (19970.39 — 8ta.)—4.5295346] = log.-' [log. (sta. + 3.41)— 3.8863124]. = log.-' [log. (Bta. — 21470.77) — 5.2172615]. = log.-' [log. (sta.— 5.69) — 5.2694635]. = log.-' [log. (sta.- 21611.00)— 4.3667876]. substitute (sta.) the valu sta.). By i.9444414]. Proportional part Proportional part 2.79 Proportional part .08 Proportional part .11 Proportional part .98 It will suggest itself to anyone that tbe above method of deriving an offset, while being the first and natural method, is exceedingly awkward and laborious. In nearly every case tbe monument site was selected in the field, and a simpler ])laii was a desideratum. Tbe writer there- fore devised by familiar methods the following empirical foiinube, which exactly represent the desired curve and will be found to be of exceptional simplicity when put in actual use. It will be noticed that only one new logarithm is involved for any given case, and in actual practice less than one minute served to determine tbe offset : Offset (by empirical formula'). log.-i (21og.3ta. — 7.3140232) — log.-i (log. sta.- 3.2849093) + 3.33 — tangent error : log.-l [2 log. (19973.80- sta.) —7.3140232J —log.-l [log. (19973.80- sta.) —4.5303464] + ■ ■E. of sta. 1672.65 = log.-i (2 log. sta. — 7.3140232) + log.-' (log. sta. — 3.88624.14) + 4.14; W. of sta. 1672.65 = log.-l (2 log. sta. — 7.3140232) + log.-i (log. sta. — 4.7877796) + 4.33; log.-l (2 log. (sta. — 1678.00) —7.3140232] + 8.04 ; log.-l [2 log. ;sta. + 55.14) -7.3156868] + 2.44. log.-l (2 log. sta. -7.3156868) + log.-l (log. sta.— 4.3645775) + 1.09. S. Doc. 2i7- -13 138 UNITED STATES AND MEXICAN BOUNDARY. Augles iu liist and second sketches below subject to correction, depending on distribution of back azimuth error of +23".8, and also for changes in distances due to remeasurements. The back aziunitii error is assumed to have occurred in three equal parts at heliotrope stations (initial points of prolongations) K, 3 I, and 4 L. SKETCHEiS ON AZIMUTH LINE. The two sketches next above show the assumed di.stribution of azimuth error and the geomet- rical conditions governing the offset formula for the field location of the monument line. FORMULA FOR AZIMUTH LINES. The formula- and tables of U. S. Coast and Geodetic Survey, Appendix No. 7, 1S84, are very convenient for short lines and secondary triaugulatiou, but give approximate results only witli lines of great length, such as occur on this survey. The following formuhc give results of the greatest exactness even ou lines of several hundred miles iu length. Given qj = latitude of first point. Given A = longitude of first point. Given a = azimuth at first point toward second point. Given & — distance from first to second point. UNITED STATES AND MEXICAN BOUNDARY. 139 To find f//, A', rt', of second point: ^ s e- d^ siu.^ 1" ^ = Tsin.T" + - eir^r^^r ''''^ '^ *'"^- ^'^ e'^ /^ ' sin. 1'' _ ^ , ^, i(l-e^) tan. 4 {,.■ + C- ^ A) =«ii^:Hi^cot.« ' sm. .J {y—6) 2 tan. .} («-■ + r + A A) ^ "-f /~^ cot. COS. Hk— ^) , COS. h{y+d) s sin. J («' + r — «) r «' sin.- 1" ..,„,, ,~^ The second term for 6 is insensible except for very great values of s. Z is always a very small angle, and is to be used with its algebraic sign, a and meters as the amount oint. The iVont hcliotroper having placed his liclioli(i|.c over a distant point on the line, and the iiistru ncnt being at a known point, a second hciidtiiipcr placed himself approximately on line between the in^t^nMlCMt and the front hcliotroper, near the proposed site of a station, and sliowcd a light to tlui instrument. The small angle between the two heliotropers was then measured with the eyepiece micrometer. The observer next telegraphed the result to the near heliotroper, using the Morse alphabet by long and short flashes from a heliotrope kept at the instrument for that purpose. The message as received Ijy the heliotroper indicated to him how many divisions of micrometer he was from the line, and in what direction. Knowing that each division was eijuivalent to mm. per kilometer of distance between him.self and the instrument, he converted divisions of micrometer to linear nieasurement, using his best judgment as to his distance from the instrument. This measurement hi' made upon the ground with a 20-meter steel tape, and placed his heliotrope at the new position. The process of measuring the angle between the two heliotropers and telegraphing the result was then repeated. The first offset, as measured by the heliotroper, necessarily corresponded to the difference on the micrometer indicated l>y the first and second messages from the observer, and therefore served (o dcfermine the distance from the heliotrope to the instrument. Using this known distance the helidiKipcr computed the offset necessary to place him on the line, and again placed his heliotrope by nieasurement. This process was repeated until the angle between the two heliotropes was ai)parently less than two divisions of the micrometer. The final nieasurement of the angle by 27 pointings with eyepiece micrometer on the heliotrope ended the operations for that station. The pointings were taken in .sets of three alternately on each light. As soon as the measurement was completed, " (). K." was sent to the near heliotroper, and he proceeded to mark the station and move on to the next. 146 UNITED STATES AND MEXICAN BOUNDARY. Whenever coiiveuieut, as determined by the topography, position of camp, means of trans- portation, etc., the instrument was moved forward to some one of the newly determined points and the process of lining in points ahead was continued. In some cases the points, about 2 kilometers apart on an average, were lined in ahead from a single station for as much as 14 kilo- meters. In other cases the instrument was moved up at every station, so that it was never more than about 3 kilometers from the point being set. In a few cases the instrument was lined in between two known points, one ahead and one behind, but this plan was avoided as much as possible because it was much slower than the usual method. After the heliotroper first showed his light near a proposed station, the time required to place his heliotrope within two divisions (2.5") of the line and to make the final measurement of tlie small angle by 27 micrometer pointings was usually from thirty minutes to one hour. Jlucli more time was spent in traveling to and from stations than was required for the actual instrumental work. The final measurements of the small angle between the two heliotroper. made it possible, by the use of the distances afterwards determined by the topographical party, to compute the small oft'set from the station as placed to the true line. These small ott'sets were computed and furnished to the monument party. The first extant monument from Monument No. 11 (204) near the Colorado was Monument No. VI ^175), 1G3 kilometers to the eastward. Before the line party began its work, a reconnaissance party, under Mr, .7. L. Van Ornum, assistant engineer, had, by the use of engineer's transits, placed a point on the Tinajas Atlas Mountains as nearly as possible on the straight line joining Monuments II (204) and VI (17.'J). The front heliotroper was placed at this jioint, Station XXXVIII, and the line was run toward it from Monument No. 11(204), a distance of 73 kilo- meters. With the instrument at Station XXXVIII, and with a heliotrope at Monument No. II (204) as a backsight, the line was produced by a single sight to the most distant visible point on the line, Station LI I in the Tule Mountains, 25 kilometers ahead. The intermediate points were then located by running toward Station LII. From Station LIl the most distant visible point on the line ahead was Station LIV, but 4 kilometers away, on the same range of mountains. Prom LIV again there was no chance to take a sight longer than 4 kilometers, to Station LVI, on the same range. At LII and LIV the original line was produced. At LVI the line was turned to run directly to Monument No. VI (175) as a foresight, and the small angle measured. In eacli of the cases in which the line is said to be produced there was in fact a small outstanding angle in the line which was measured with the micrometer. These five sections represent the longest sights possible in running the line, for in each case the forward sight was taken to a station which was against the actual sky line as seen from the preceding station. The computation of offsets showed that Station XXXVIII was 0..S7 meter north of the straight line joining Monument No. II (204) and Monument No. VI (175). The greatest offset from any station on the line as run to the straight line joining the monuments was 0.99 meter to the southward, at Station LV. From Monument No. VI (175) to Monument No. 27 (127), with one exce])tion, each monument was visible from the preceding one, and the line was located by running forward from cacli monument to a heliotrope placed on the next monument. From Monument No. XII (100) the view to Monument No. XIII (150) was shut out by a sharp peak of the Lesna Mountains, about 33 kilometers from Monument No. XII (100) and l."> kilo- meters fiom Monument No. XIII (150). This peak, although not high, had faces so nearly vertical that it was difficult to climb. It was found on a preliminary investigation that at the point where the line crossed the peak the top was so narrow and so unsafe that it would be dangerous as well as extremely difficult to place the theodolite there. Accordingly the theodolite was placed successively at two points, which maybe called A and B, about 10.") meters apart on a rocky bench on the south side of the peak, and the angle at each point between Monument No. XII (100) and Monument No. XIII (150) was measured with the micrometer. The linear measurement between A and B, in connection with the angular measures, showed that the line was about 25 meters to the northward of the northern point, A. This measure was then made with considerable UNITED STATES AND MEXICAN BOUNDARY. 147 difficulty along the dobris at the foot of the west vei-tical face of the peak, aud Station XVI was established. Afterwards Station XVII was placed accurately on the line Monument No. XII (IGO) to Station XVI produced on the top of the peak, and Station XVIII was placed near the east foot of the peak accurately on the line Station XVII to Monument Xo. Xltl (1.50). All pointings upon Station XVII were made upon a short 1-inch pole held in position by hand, and the station was marked by a cross cut in the surface of the rock. The intermediate points were put in between Monument No. XII (100) and Station XVI and between Station XVIII and Monument X^o. XIII (150) in the usual way. The angles at Monument Xo. XII (160), between the back-sight (jNIonument No. X [102]) and each of the points Station XVI, A, and B, were measured with micrometer, and also the angles at Monument No. XIII (150), between the fore- sight (Monument No. XIV [I4GJ) aud each of the points Station XVIII, A, and B. These, measured, gave three of the four angles of each of the four-sided figures — Monument No. XII (IGO) to Station XVII, Monument No. XIII (150) to A, and Monument No. XII (160) to Station XVII, Monument No. XIII (150) to B — ^and therefore from each figure there was derived a value for the angle at Station XVII between Monument No. XII (160) and Monument No. XIII (150). These two vaules were 180° 21.5" and 180^ 19.2". The mean, in connection with the stadia distance along the line, gave for the offset from Station XVII to the line joining Monument No. XII (100) and Monument No. XIII (1.50) 0.91 meter south. This procedure gave a strong azimuth connection past the difficult point, and gave the ditterent otfsets independently of the rough linear measurement along the debris on the west face of the peak, which served for the first approximate location of the line. The com])nted value for the offset at Station XVII is i)robably as accurate as would have been obtained if that station had been occupied in the usual way. If the lines Monument No. II (204) to Monument No. VI (175) and Monument No. XII to Monument No. XIII, which could not be run with a single foresight, be omitted, there are but 16 cases in which the eomxiuted offset from the station as set to the line joining adjacent monuments was greater than 0.10 meter, and the greatest offset was 0.31 meter. The azimuth of the line Monument No. II (204) to Station XXXVII was determined by the Yuma triangulatiou. (See astronomical report.) All the angles in the line as run were measured with the micrometer, save the angle at Monument No. VI (17.5). That angle, being too large (55') to measure witli the micrometer, was measured with the theodolite used as a repeater. The instru- mental lino was finally connected with the line B to No. 7 of the Nogales triangulatiou (see astronomical report) by measuring with the theodolite used as a repeater the angle at B between Monument No. XVIII (129) and No. 7. The azimuth of the line B to Monument No. XVIII (129) as computed from the Yuma triangulatiou and the measurement of angles along the boundary was 6.7" greater than the azimuth as given by the Nogales triangulatiou. This difference of 0.7" arises from the errors in the Yuma and Nogales azimuth observations, the errors of the Yuma and Nogales triangulations, and the measurement of 16 angles along the line. The computations of geographical positions were made as follows: The distance on the Clark spheroid between Monument No. II (204) and ]VIonument No. 27 (127) was first computed from the latitudes and longitudes of those two points as given by the Y'nma aud Nogales triangulations. This distance as thus computed may properly be called the astronomical distance, as it depends ultimately upon astronomical observations at Yuma aud Nogales. The distance from Monument No. II (204) to Station XXXVII on the Tinajas Mountains was determined by the Yuma triangu- latiou. This being subtracted from the astronomical distance between Monument No. II (204) and Monument No. 27 (127) gave the astronomical distance from Station XXXVII to Monument No. 27 (127). The direct stadia measurement by the topographical party gave for the distance between Station XXXVII and Monument No. 27 (127) a value exceeding the astronomical distance by 301.85 meters, or one part in 994. The stadia distances on each separate section of the Une between those points decreased in that ratio to agree with the astronomical distance were theu taken as the true distances between the monuments. Using these distances, the known latitude, longitude, and azinuitli at Monument No. II (204) and the measured angles along the instrumental line, the geogra])hical position of each monument, aud the azimuths of each section of the instrumental line were computed. This computation 148 UNITED STATES AND MEXICAN BOUNDARY. developed the ac.cnninlated aziumtli error lyiiij!: a correlation of 0.C7" to each of tlie ten angles at Monuments No. VI (175), IX (Hi3), X (102), and XII (KJO) to XV'III (i:^'.)), and the computation of geograpliieal positions and azimuths made again with tlie corrected angles. In these computations all lines except Monument No. II (204) to Monument No. VI (17.5) and Monument No. II (-204) to Monument No. 27 (127) were computed by the fornuihe and factors of Appendix No. 7, Coast and (ieodetic Survey Report for 18S4. Tlu' long lines named weie (ioraputed by the more accurate fornuila' of Appendix No. !•, Coast and txeodetic Survey Iteport for 188.'). IltoVI VI to IX IXtoX XtoXII , XII lo xm.... xiirtoxiv ... XIV to XV XV to XVI XVI to XVII... XVII to XVIII xvm to XIX XIX to 27 162, 970. 5 102, 918. 9 31, 352. 9 31,319.6 23.435.2 23,409.9 7. 280. 4 7, 281. 4 40, Ml. 5 40,550.2 19,881.0 19, 859. 27,580.2 27, 548. 7 14,759.3 14,741.8 4,230.8 4,231.8 28,981.3 28, 940. 5 .5,047.3 .5,040.3 394.1 393.0 290 08 30 20 50 24 30 20 20 The latitude of Station P., as thus computed tlirough tlie wliole Hue, is M° 19' 59.24", and from the Nogales triangulation is .il ^ 20' (t;5.70". Tlie difl'ercnce, 4. 1(i", re[iresents the difference of station errors in latitude between Monument No. II (-04) and Station B. The longitude of Station B, as computed through the line, differed from its longitude from the Nogales triangulation by 2.01". Tiiis difference is the indirect effect of the latitude station error upon the computation, and not station error in longitude, for the measured distances had already been corrected to agree with the astronomical distance. The latitude station error, 4.40", and the longitude difference, 2.01", were distributed propor- tionally to the distances of the various monuments from Monument No. II (204). (Note. — The linal results for the latitudes, longitudes, and azimuths of these old monuments computed from the mean of the measures of distances and angles, made by both United States and Mexican sections, and the latitudes corrected to conform to the mean latitude of the whole boundary, will be found in Report of Joint Commission, page 99.) The offsets from each monument to the straight line joining Monument No. II (204) aiul Monument No. 27 (127) were then determined by computing the latitude and longitude of a point on said straight line opposite each monument. The offsets irom the straight line to each monu ment, at right angles to the straight line, are as follows, all to the southward: Monument No. VI (175) 1,413.2 Monument, No. IX (168) 1,18X6 Monument No. X (162) 1,023.8 Monument No. XII (160) 974. 9 Monument No. XIII (l.'.O) 657. 7 Mouument No. XV (141).... Monument No. XVI (137). .. Monument No. XVII (136).. Monuni-MitNo. XVIII (12S). MoniimoMt No. XIX Monument No. XIV (146) 540.8 I On the whole line the work was pushed forward at all times without reference to favorable or unfavorable conditions for accurate observation. It was considered that such a procedure would give all needful accuracy, and that economic considerations would not Justify any additional expenditure. Much of the observing was done under conditions that at first sight would .seem likely to lead to large errors, and it is therefore more than usually desirable that the accuracy of the determinations should be put in evidence. A study of the method of work and of the instrument leads one to the conclusion that the errors in the location of the various points on the ground arise almost entirely from two causes, lirst, instability of instrument during ob.servations, and, .second, errors of i)ointing. UNITED STATES AND JIEXICAN BOUNDARY. 149 Inasmuch as the instrument was simply mounted on its own tripod, and was witiiout protec- tion from sun or wind, it was subject to irregular movements due to its e.\i)osure. The routine of observation was especially designed to cancel out the effect of such movement upon tbe result. The mean time of the jwintings on each of the two points concerned in any determination was made as nearly identical as possible and the pointings were taken in rapid succession. The 137 pointings constituting the linal determination of a point were made iu from ten to tbirteen minutes. An idea of the magnitude of the errors ainsing from this cause can be gained by noting tbe average ditterence between each set of observations and the mean of the sets, as stated later iu this report. The value of one division of the striding level was 3.68." The level was applied so often, and the inclination of the line of sight was usually so small, that the errors from this source must be almost inappreciable. By "errors of pointing," as used above, must be understood, not only the errors made in attempting to place the observing thread upon the brightest point of the heliotrope light as seen, but also the errors arising from the assumption that the apparent position of said brightest point coincides with the actual center of the heliotrope mirror from which the light issues. From Jlay 8 to the end of the work a record was kept during ol)servations of the apjiearance of the heliotropes, of the temperature, and of the apparent diameter of the heliotrope light as measured in divisions of the eyepiece micrometer. The temperatures were taken with a centigrade thermometer jilaccd iu the most extensive shade available in the vicinity of the instrument, which was usnnlls tlic little shadow cast by the instrument box. There are but few cases in which the recorded temperature at observation is below 25° C. (77° F.). During June and July the greater number of the recorded temperatures were between 35° 0. (95° F.) and 43° C. (109° F.\ In a single case, on June 24, between 1 and 2 p. m., the temperature indicated by the thermometer hanging iu the shade of the instrument box was 48° 0. (118° F.). The apparent diameter of the light of the heliotrope in divisions of nucrometer (each 1.24") varied from live or six divisions, in a few rare cases, either early iu the morning or under a clouded sky, through the intermediate values to the other extreme, when the apparent diameter was 104 divisions. This last case occurred between 11 and 12 on a very hot July day on a line of sight about 2 kilometers long, which was within 3 meters of the almost bare sand. The average appar- ent diameter of the heliotrope lights for the season was twenty-five divisions (31"). The diameter of light as measured includes only what might be called the solid part of the light, and excludes the rapidly changing rays and spots of light which sometimes formed a further irregular extension. The principal mirror of the heliotrope, called in this report "R," was round, with a diameter of 10 centimeters, and that of the heliotrope called "G" was round, with a diameter of 7.5 centi- meters. If the mirror itself were seen with the telescope, it would appear as an ellipse with the major axis equal to the diameter of the mirror. The measured angular diameter of the light as seen, taken iu connection with the known distance to the heliotrope, shows that the mirror itself was visible only on very rare occasions even when the conditions were favorable. tJsually the apparent width of the object upon which the pointings were made was many times that of the heliotrope mirror. For example, iu the case in which the light appeared 104 divisions in diameter it corresponded to a target 1 meter iu diameter, placed iu the position of the heliotrope 1,000 meters fi-om the instrument, although the diameter of the mirror was only 7.5 centimeters. On May 15, with the temperature iu the shade 39° C. (102° F.), a heliotrope mirror 10 centimeters in diameter, 43 kilometers distant from the instrument, showed as a blaze of light 44 divisions (55") iu diameter, corresponding to a target, in the position of the heliotrope, 11.4 meters iu diameter. The characteristic appearance of the heliotrope light, as seen during the observations, over highly heated and nearly bare sand or rocks, was a bright blur of light with outline but poorly defined. Each separate portion of the outline seemed to be vibrating violently. Usually there was a iiart of the blur considerably brighter than the remaining portions, and the brightness increased gradually from the outline inward toward this region. In the most frequent case this bright region was in the center of the blur, and the extent of the vibration on all parts of the 150 UNITED STATES AND MEXICAN BOUNDARY. outline was about the same. It frequently occurred, however, that the outline was decidedly unsymnietrical with respect to the brightest region. In those cases the brightest region was always to windward of the center of the blur, and the leeward part of the outline vibrated more violently than the windward side, the whole appearance being much like that of flames blown sidewise by the wind. lu all cases the pointings were made upon the assumption that the actual position of the mirror was represeuted by the brightest portion of the blur, and not uecessarily by the center of the blur. As a rule, the violence of the vibration of the light increased ^vith increase of apparent diaiu eter. The size of the light and the violence with which its outline vibrated was apparently greater for lines which were near the ground than for high lines, aud less during a steady breeze than when the wind blew in gusts and whirls, or when the air was still. Evidently there were various other unknown causes producing large and apparently accidental changes in the appear- ance of the light. This makes it necessary to base any reliable conclusions upon a considerable number of observations at various stations and on many different dates. Accordingly, in the investigation as to apparent diameter of light and accidental errors of pointing, of which the results are given below, all available observations from May 8 to the end of the work were used. The pointings upon each heliotrope were made in sets of three pointings each, taken in quick succession. A convenient measure of the accidental errors of pointing is the mean of the differences between each of the pointings and the mean of the three. This mean difference may be called J 3. Variation of apparent diameter of light and of J 3 with the time of day. Hours. Heliotrope R. Hours. Heliotrope C. Diame- Number observa- tions. A3 divisions. Number observa- tions. Diame- i Number 1 . , Number ter ill 1 observii- ',i;,„^j„.,„ observa- divisions.; tions. d"'i3iou8 ^.^^^^ 6 7 12 18 19 I 42 24 32 21 16 ^ 0.78 .90 .73 .94 1.12 1.08 1.05 1.02 .68 11 21 24 6-7 18 28 25 27 34 31 22 49 28 23 37 38 18 16 12 12 0.57 ' 11 .84 27 74 .11 7-8 8-9 ... 8-9 .91 .85 1.00 .76 1.00 .47 40 27 18 5 4 16 14 14 6 8 1 4 9 12 12 1 , 1 2 •1 The mean diameter of light for Heliotrope K was 23 divisions {'29") and for Heliotrope C 27 divisions (34"). The mean value of J 3 was O.SS division (1.09") for "E," and 0.80 division (0.99") for "C". Very few of the observations were made within an hour of sunrise or of sunset. The table shows incidentally the hours most frequently used for observing. UNITED STATES AND MEXICAN BOUNDARY. 151 Variation of ajiipareitl diameter of light for different distances betivven the theodolite and hdiolrojK Heliotrope R. - Heliotrope C. | Di8 tance. Diame ter in divisions. Number- observa- tions. Dis- tance. Diame- ter in divisions. Number observa- tions. Kilome- Kilome- 2 19 ters. ^ 41 7 3 23 37 44 i 13 31 22 5 24 24 15 6 19 23 21 7 27 26 16 8- 26 17 12 10 20 2 27 18 11-U 26 18 16 4 15-19 23 30 24 6 20-24 26 19 11-14 24 10 25-29 11 12 15-19 18 14 30-34 17 7 20-24 19 4 35-39 35 7 25-29 i 13 7 43 33 5 1-2 37 51 56 13 6 3-5 26 58 2-14 24 40 1 6-9 24 50 15-24 24 49 10-29 j 20 41 25-56 20 37 Variatitn of A J for different diameters of light. Heliotrope E. Heliotrope C. Diame- ter in divisions. A3 divisions. Number observa- ter in divisions. A3 divisions. Number observa- | tions. 1 0-5 0.77 0- 5 0,37 1 4l 6-10 .58 6- 8 .45 6 11-15 .70 20 9- 11 .62 6 16-18 .85 12-14 .65 18 19-20 .95 15- 17 .64 19 21-22 .84 18-20 .68 24 23-24 .66 21- 22 .90 10 25-26 .88 23-25 .67 26 27-28 .92 26- 28 .69 20 29-30 1 1.15 29-30 .70 5 31-32 .83 31-32 .77 6 33-34 .90 33- 34 .63 4 35 1 .83 35-37 .97 7 36-38 ! 1.00 38-40 .65 4 39-44 1.40 41-44 1.20 9 45-49, 1.12 45- 49 1.23 7 50-60 1.90 50-60 1.54 11 61-67 1.70 61-104 1.29 10 0-15 .66 42 O-20 .63 77 16-28 .85 46 21- 34 .71 71 29-67 1.15 38 35-104 1.22 48 The table shows that the aucidental errors of pointiug iucrease much more slowly thau the apparent diameter of light, in spite of the ftict that with increased diameter there is also increased vibration; and shows that, iu so far as accidental errors were concerned, it was safe to observe even under the api)areutly abnormal conditions when the diameter of the light as seen was from 1' to 2'. J 3 eqvial to l.li divisions corresponds to ±2.7" for the probable error of a single pointiug. 152 UNITED STATES AND MEXICAN BOiMNUARY. The tinal deteniiiuatiou of each statiou liued iu ahead of the iustrumeut consisted of three sets of nine pointings each. A convenient measure of the accidental errors of the sets is the mean of the differences between the result from each set and the mean of the three results. This mean difference may be called J S. The actual relation between A S and J 3 is shown in the following table, in which the first column is the mean z/ 3 for the two heliotropes: Uivi^iL« AS divisions. Number observa- A3 aivisions. AS divisions. Number cibserva tions. 0.0-0.3 0.30 1 0.98 .4 .45 12 .87 .h .80 3 1.32 .0 .70 20 .95 .7 .54 7 1.5-1.6 1.05 .8 .83 15 I. 7-2. 2 .80 .a .94 7 . 0-. 7 .60 42 1.0 .78 5 . 8-2. 2 ___:" 44 J8 = (i.02(i (-oiresponds to ±li.l" for the probable error of a single set, and ±1.13" for the probable error of the mean of the three sets. J S is appaiently proportional to z/ 3, but is about three times as large as would be accounted for by the influence of J 3 alone. Only a limited time was available Ibr experimental work in the field, but the following evidence in regard to the magnitude of the constant or systematic errors arising from the use of heliotio])es was secured as opportunities presented themselves: On May 8, in the Tule Mountains, a series of observations were made for the purpose of determining whether there was any apparent displacement of the light when the heliotrope was neglected, and also to determine whether the apparent position of the light coincides with the actual position of the lieliotrope mirror. The line of sight passed from one high ridge to anothei' high ridge, about -1 kilometers distant, over deep cafions and intervening ridges reaching nearly up to the line of sight. Pointings were made in quick succession upon a 1-iuch pole carrying a tiag and upon the heliotrope accurately in line with the pole and within 2 meters of it. The mirrors of the heliotrope having been adjusted, the observation.s (•(intinucd for fifteen to twenty-five minutes before the mirrors were again readjusted. During tlic ohsii \ ations tlie helio trope light appeared to be from 4 to 15 divisions in diameter. The whole .scries of observations comprise 47 pointings on the pole and 195 upon the heliotrope, extending over a half hour in the forenoon and about two and a half hours in the afternoon. The mean result from all the obser- vations is that the heliotrope light seemed to be 0.15 division = 0.19" = 4 mm. south of the pole. The observations do not show conclusively that there was any apparent change iu the position of the light when the mirrors were neglected. If there was any such change it was masked by the accidental errors of observation. The accidental errors of pointing seemed to be slightly greater when the mirrors were first adjusted than later, when the light had become less bright and a[)i)arently smaller. On June 7, at Station VI of Line B, 20 sets of observations of 12 pointings each, extending over four hours, were taken to ascertain the effect of reducing the mirror on Heliotrope from 7.5 cm. in diameter to 2.5 cm. Heliotrope was at Station IV, 5,800 meters to the westward of the instrument, and Heliotrope R was at Monument No. IX (168), 17,400 meters to the eastward. The average ajjparent diameter of the light from Heliotrope was 25 divisions when the full size of the mirror was used, and 23 divisions when the light was reduced by passing through a hole 2.5 cm. in diameter. The reduced light seemed to be but slightly less bright than the full light. The acci- dental errors were as great with the reduced as with the full light. The mean of the 10 sets with the full light gave Statiou IV 2.8 divisions north of the line Monument No. IX (1(18) to Station VI l>roduced, and the 10 sets with reduced light made it 3.1 divisions north. There was a remarkable difference between the forenoon observations and those made in the afternoon. The mean of all sets in the forenoon gave Statiou IV 5.9 divisions north of the line Monument No. IX (168) to Station VI produced, and the mean of all the sets iu the afteruoou made it but 1 division north. UNITED STATES AND MEXICAN BOUNDARY. 153 The original deteriniutitiou of the position of Station VI from Station IV, on June 5, would make Station IV 0.2 division north of the line Jlonument No. IX (168) to Station VI produced. This extreme range of 5.7 divisions in the three values corresponds to a range of 0.20 centimeter in the position of Station IV. This remarkably large range of results led to a special investigation at Monument No. IX (108), on June 15, to determine whether there was a systematic difference between forenoon and afternoon observations, and whether there was any systematic error due to the position of the back glass, wliich was used to reflect the sunlight to the main mirror of the heliotrope when the sun was behind the heliotrope from the observer. Eight sets of nine pointings each were taken in the forenoon, and fourteen sets in the afternoon. Ileliotrope C was used at Station IX, Line B, 7,700 meters to the westward of the instrnment and its position compared with that of two flag poles nearly on line at Stations X and XI. The apparent diameter of the light during observations was from 16 to 24 divisions. Taking the pointings upon the flag poles as a standard, the hehotrope appeared to be 0.0 division farther south in the forenoon tlian in the afternoon. During the forenoon observations the sun was to the northward of the line of sight, and during the afternoon observations to tlie southward. In the afternoon every alternate set was taken with the back glass to the southward of the line of sight, and the remaining sets with it to the northward. To exaggerate the eftect, if any, the back mirror was purposely placed so that the line Joining the centers of the two mirrors made a horizontal angle of about 50° with the line of sight from the instrument. The mean of seven sets with back mirror soutli agreed exactly with the mean of the seven sets with back mirror north. For the purpose of detecting constant errors the line from Station IV, Line E, to Station XV, 25,800 meters long, was located independently both by lining in points ahead in the usual way, and by lining in the instrument between two known points, one ahead and one behind. Errors of pointing upon the forward heliotrope will affect both these locations alike. But errors in pointing u[)on the other heliotrope will have contrary effects in the two cases, making the located line too far north in the first case, and too far south in the second case if the heliotrope appears to be farther soutli than its true position. The greatest difference between the two locations at any of tlie ten intermediate stations was 32 centimeters, and the average diflerence was 17 centimeters. With one exception, all stations as located by the second method were farther south than by the lirst method. During the observations for these locations the lieliotropc lij;lit appeared more than .id ilivisions in diameter during a third of the time, and on one (iccjsidn ujiiieared 101 divisions in diameter. Tiie lines of siglit were usually near the gronnd. Tlierc were several cases where the light appeared decidedly unsymmetrical, and the conditions generally were as unfavorable to accurate work as on any part of the whole line from tlie Colorado to Nogales. As one more evidence of the reliability of the pointings upon the heliotrope, even under such unfavorable conditions as those encountered during the season, may be mentioned tlie azimuth error of 0.7" as developed in connecting with the Nogales triangulation. The measurements of the various angles in the line as run were made upon heliotropes under conditions no more favorable than during the other jiortions of the work. CIIAPTKi; V. TOPOGRAPHY. For measuring the distance along the boundary line, three general methods were considered: 1. Triangulation. 2. Chaining. 3. Stadia measurement. The method by triangulation is by far the most accurate, but it is slow and expensive, and in the present case would have added very greatly to the ditticult ])roblem of providing water and supplies for so many different parties. For these reasons, therefore, it was deemed impracticable. The method of chaining is cheap and sufficiently rapid, and the work can be carried on under conditions of weather when triangulation and stadia work would have to be suspended. It has tlie disadvantage of reciuiring more cutting in a timbered country than does the method by S. Doc. 247 14 154 UNITED STATES AND MEXICAN BOUNDARY. Stadia; of not beiog under the eye of au employe of a high grade of intelligence; of giving neither heights nor angles, and of being entirely impracticable in a rough, mouutainous country, or in one badly cut up by canons, wliich is the case with a considerable part of the country along the International Boundary Line, while even in hilly and rolling country it is less accurate than the stadia. On level ground and for distances of a few kilometers the chain is possibly the more accurate; but these limitations for greater accuracy practically debarred it from use in tiie case considered. The method by stadia is cheap and rapid; requires less cutting than that by chain; is carried on under the eye of an instrument man, presumably of a high order of intelligence; gives heights and angles, and enables objects to be located from the line which is being measured; is ordinarily more accurate than the chain, and can be successfully used where the chain can not be, experience on this survey having shown that the stadia lines over mountains, hills, and canons were more accurate than those on level plains and wide valleys. It was conditionally decided, therefore, to measure the distances along the boundary line by stadia, and to take astronomical observations for latitude, longitude, and azimuth at or near the fixed extremities of each of the six sections of the boundary, which would serve tlie double purpose of locating these points and of checking the measured stadia distances between them. In addition, these measmemonts were also checked in several jdaces by triaugulation. That there should be, however, no question as to the relative accuracy or adaptability of chain and stadia for this work, and as each would serve as a check on the other during the earlier stages of the survey, when all observers were inexperienced in working under tlie conditions then existing, it was decided to measure the entire distance along tlie boundary on parallel 31° 47'— 159,193.4 meters— both by chain and stadia, and then from the experience so gained select the method best suited for the survey. The distance thus measured was i)eculiarly favorable for chaining, being in general Hat and destitute of trees. The greater part of this distance had been covered by a well planned triaugu- lation made for the Mexican Government by Senores Molina and Gontreras in 1855, and it is with their results, being unaffected by station error, that comparisons are made. As it is believed that such a comparison of the relative values of the two methods of measure- ment, on so extensive a scale and under conditions so identically the same, has seldom been made, the results are given in detail in the following table: Distanves alomj iianillcl 3V-> 17' determined by triaiuinlation, stadia, ami chain. Triaugula- Stadia. S:^ .(Corrected chain. Error of corrected chain. Meteri. 19,971.1 21, 500. 7 13,192.9 21,028.8 22, 819. G Meters. 19, 07U. 4 21,472.6 13,170.9 21,597.9 22, 812. 5 1/28530 1/765 1/600 1/700 1/3214 Metert. 19,964.7 21,474.2 13, 193. 2 21,605.3 22,804.1 1/3120 1/811 1/43976 1/920 1/1472 99, 113. 1 99, 024. 3 1/1116 99, 041. 5 1/1373 If, instead of averaging the errors of the stadia and chain on the above five sections, con- sidered separately, these sections are taken as one continuous distance, the errors of the stadia and chain become 1/lllG and 1/1384, respectively, the very small change being due to the fact that practically all of the errors had the same sign. From the preceding table alone it would appear that over country of this character tlie cliaiii is more accurate than the stadia, but such was not really the case; for during the measurement of parallel 31° 47' the stadia six times detected the dropping or addition of a chain length— 20 meters. These have been corrected in the preceding table, but would have escaped notice entirely had not the chained distances been compared each night with the stadia distances, and remcasuremeuts made whenever serious discrepancies between the two were discovered. In every such case it was found that the addition or omission of a cViain length had caused the discrepancy. UNITED STATES AND MEXICAN BOUNDARY. 155 The stadia having proved superior to the chain in a region peculiarly favorable to the latter, and there being no question as to its superiority in the mountainous region yet to be encountered, the use of the chain was thenceforth abandoned. The wisdom of this action became more fully confirmed with every day's progress of the work. The measured distances along the boundary were used as bases in the topographic work. Locations were made principally by stadia, but in some cases by tlie method of intersections. Datum points for heights were given by a careful line of levels carried along the boundary from the Kio Grande to the Pacific. Occasionally the topography was "filled in" from located points by aid of the prismatic compass, hand level, and sketching. Between the Pozo Verde Mountains and the Colorado River — a distance of more than 323 kilometers— the region bordering the boundary line is difhcult of access, remote from railroads, is practically uninhabited by Americans (there is but one American ranch within 30 kilometers of the boundary line on the United States side), and is a true desert, containing but five badly spaced permanent watering places in the entire distance. Owing to these causes, and in order to expedite the work in this inhospitable region, it was decided that between the west end of parallel 31° 20' aud the Colorado Itiver a topographic belt, 1 kilometer in width, adjacent to the boundary line, would be surveyed and plotted in the usual manner; but that the remainder of the 2i mile belt of topograi)hy would be taken by placing flags on all of the prominent peaks, ridges, and other natural objects, to be located by the transit man engaged in measuring the boundary line. Another transit man would then occupy these positions and from them locate all flags in sight. Other important topograi)hical features were then to be located either by stadia or by resection, and contoured sketches of the immediate vicinity made. Subsequent events justified the wisdom of the plan adopted, for even with this more expeditious method there were times when tlie scarcity of the water supi)ly threatened serious interruptions to the work, and slower progress would undoubtedly have been fatal to its contin- uous prosecution. All heights, except those on the line of levels, were obtained by reading tlie vertical angles of the points located. For a time aneroid barometers were tried for obtaining heights, and the results were checked in each case by comparison with the line of levels. Although great care was used, and every possible precaution taken, the results obtained by the use of these baroiieters were found to be too unreliable, and their unavoidable errors too great, to admit of their use on a work where contour intervals were fixed at 20 meters. From the coniMiencement of field work in February, 1892, until its close in October, 1893, Mr. J. L. Van Oruum, assistant cngineei-, was in charge of the topographic party, which during that period operated between the Rio (irande and the Colorado rivers. From January 24, 1893, until September 20, 1893, another topograi)hic party was put in the field under charge of Mr. E. L. Ingram, assistant engineer. Tiiis party oi>erated between the Colorado River and the Pacific Ocean. For the com])osition of these parties and interesting details of their work, see reports of Mr. J. L. Van Oruum (p. 160) and Mr. E. L. Ingram (p. 128), assistant engineers. The topographic belt proper covered an area of 1,810 square miles, in which there were 39,266 locations in all— 51 by triangulation, 2,.523 by ti ansit intersections, aud 36,692 by stadia sights- each location giving both the position and elevation of the point. In addition to those in tlie topi)graphic belt, all prominent mountain ranges and peaks visible on either side of the line were located by intersections, giving 2,785 locations of this class. The locations by intersections in the topographic belt averaged three sights each, while those outside of this belt averaged six sights each. Of the area included within the limits of the topographic belt, 360 square miles are covered by mountains, 230 by hills, and 1,220 by valleys, mesas, and deserts. The average number of locations per square mile for each of these classes is 60, 45, and 6, respectively; while the average for the entire topographic belt is a little less than 22 per square mile. 156 UNITED STATES AND MEXICAN BOUNDARY. lu explanation of these figures it should be stated that, as a whole, the iiioiiutains are extremely steep and rugged, necessitating, not unfrequently, sights the vertical angles of which varied from 40° to 00°. Some of the ranges between the Colorado River and Quitoba(iuita had such sharply defined and knife like crest.s that it was with the greatest difficulty their summits could be reached, and with equal difficulty, owing to lack of room, that a transit could be set up on the crest and readings taken. The iiills are much broken and cut up by innumerable canous, and the valleys, mesas, and deserts unusually flat aud very uniform in slope. In all, 1,092 miles of stadia liues were run. These Hues were of two classes : 1. "Main lines," i. e., straight liues run along the tangents or boundary line, and couse(iuently free from azimuth errors. 2. "Side lines," i. e., ordinary stadia lines, in which both angles and distances are determined. Of the first class 675 miles in all were run, of which five sections, aggregating 125 miles, were checked by triangulation, with an average error in distance of I in 1,218. In addition, these lines were further checked by comparing the measured aud computed lengths of all sections of the boundary except the Colorado lliver section, the data for the computatious being furnished by the astronomical observations at or near the extremities of each of these sections. These comparisons are shown in the following table: Table showing discripi ired and compHted distances along the homidary. Section.^. Computed distance. Stadia distance reduced to mean sea level. Discrepancy add algebra- ically to stadia dis- tance. Discrepancy equals 1 in— Meters. 159,193.4 49, 830. 1 272,954.2 372,887.3 225,570.2 Meters. 158,708.4 49,846.1 273, 073. 4 373, 104. C 225,151.7 + 425. - 16.0 — 119.2 -217.3 + 418.5 375 3,114 2,290 1,710 539 TOTALS OF ABOVE DISTANCES FROM INITIAL MONUMENT ON KIO GKANDE. Monuments Noa. 1 to 40. . Monuments Nos. 1 to 53 . - Monuments Nos. 1 to 127 . Monuments Nos. 1 to 201. Monuments Nos. 1 to 258. 159,193.4 158,768.4 + 425.0 209, 023. 5 208,614.5 -t 409. 481,977.7 481,687.9 + 289.8 854, 865. 854,792.5 + 72.5 1,080,435.2 1,079,944.2 + 491.0 In the cases of the first and fifth .sections of the table, the discrepancies betweeu the meas- ured and computed distances are doubtless greatly increased by the large local ditt'erences of station error which were found to exist both on the liio (hande and the Pacific coast. Tills was further indicated by the fact that there were three iudependent measurements of the first section by United States corrected chain, by United States stadia, and by Jlexican stadia, the extremes of which (liircicd h.s.s tli:in do meler.s, while their mean diflered about six and one-half times this am(mut from llir roniiMiiiMi ilisi^inco. There were two independent incasmcnicnts of tlie fifth section, by United States stadia and by Mexican stadia, which differed by less than 25 meters, while their mean tliffeied more tlian JOO meters from the computed distance. It will be observed that some of tlie preceding distances differ slightly from tliose given in the tables of final distances between monuments. This is due to the fact that remeasurements were made of all distances, wherein serious discrepancies were discovered when the United States and Mexican distances were compared previous to the erection of monuments, lu order to give a true idea of the accuracy of stadia work, the original measurements only, uncorrected by the remeasurements, are given in the preceding table, while the results of the remeasurements are included in the tables of final distances. These results are of interest, as showing the accidental errors in stadia work, wliicli occur in spite of all precautions. luasnnu-li as the United States and Mexican measurements were made UNITED STATES AND MEXICAN BOUNDARY. 157 at different times, were totally iiidepeiKlent of one aiiothei-, and were generally not compared for months after tbey were made, it is Mr to assume that the discrepancies shown by these compari- sons included the greater number, if not all, of the accidental errors of the stadia measurements. Two hundred and flftysix distances, averaging 4,235.7 meters each, were compared, and remeasurements were made wherever serious discrepancies were shown. These reuieasurenients disclosed three cases in all where it was evident that the United States measurements contained accidental errors, either in reading the rod or in recording the readings. Two of the errors were about 100 meters each, and were probably due to errors in rod reading; the third was about 30 meters, and was probably due to a clerical error iu recording. As the total number of sights taken in measuring the compared distances was 5,0.59, and as it is extremely unlikely that two errors of this character, exactly equal iu amount and with oppo- site signs (thus balancing one another), occurred in any single one of the 256 distances, when but three were found in all, it miiy be assumed that 3/.505!) gives a fair idea of the probability of an accidental error of any considerable magiutude, where the observers are intelligent, careful, con- scientious men, keep their own notes, and take foresights and backsights at each station. In all, four observers were engaged in measuring distances along the boundary line proper, and three of them had one accidental error each. In this connection it is interesting to cnmi)are the relative effect of the accidental errors of the stadia with those of the chain. In a distance of 1.53,841 meters, 7,692 chains of 20 meters each, G chains were either added or dropped accidentally, i. e., 1 chain in every 1,282, or an error from this cause of 1/1282. The three accidental stadia errors before alluded to aggregated 247.46 meters in a total distance of 1,080,435 meters, or an error from this cause of 1/4366. The preceding discussion has been entered into in detail because it is believed that seldom, if ever before, has it been possible to check in this manner work done on so extensive a scale, and thereby to determine, even approximately, the effect of errors the frequency ( f the probable recurrence of which is almost wholly unknown. Of lines of the second class 1,017 miles were run, of which 118 lines, aggregating 514 miles, were closed on points ou the main lines, by the method of latitudes and departures, with an average error in distance of 1 in 753. Twenty-five per cent of these lines showed an error in closing greater than 1 in 500; 31 per cent showed an error in closing between 1 in 500 and 1 in 1,000; 30 per cent showed an error in closing between 1 in 1,000 and 1 in 2,000, and 14 per cent showed an error in closing less than 1 in 2,000. The following table was prepared to show the effect of the seasons ou the accuracy of the work : Season. Aggregate leTgtlfof lines. Krror in dist.anco on closing Cnalsl Meiin error ou closing, per kilometer of line run. In azimuth. In elevation. Spring Metert. 138, 702. 83 298, 147. 87 152,325.01 237, 339. 65 602 728 1,090 742 , „ 1 24 45 1 01 1 07 Meters. 0.103 .141 .101 .128 Winter 826,515.90 752 59. G .123 Topographic field work was commenced in February, 1892, and carried on continuously until completed, in October, 1893; and in preparing this table the seasons, for couvenience, were divided as follows: Spring: March, April, May. Summer: June, July, August. Autumn : September, October, N'ovember. Winter: December, January, February. An inspection of this table .shows that the least accurate work w.as done in spring, and the mo.st accurate in autumn — a result which was due partly to inexperience on the jiart of the observers 158 UNITED STATES AND MEXICAN BOUNDARY. during the spring of 1892, but more especially to the effects of work done ou the Yuma Desert in March, 1S'J3, under conditions very unfavorable for accuracy. The same lines were then grouped with reference to length of courses, in order to determine how tlieir accuracy was affected thereby. This grouping is shown in the following table: Numbor III- lines. •iS- '^ofH!''' Average immbei^of pri'ne. Average error in distauceon equals 1 in— Average error on closin", per kilometer of lino run. In azimuth. In elevation. 29 28 12 118 Meters. 111,823.2 280.700,8 290,033.9 143, 3.12. Meters. 253.0 350.7 437.7 580.4 1.5.2 10.1 23.7 20. G 553 782 817 780 ■ " Meters. 1 r,5 0.160 1 04 .096 43 .103 37 1 .190 820,515.9 386.2 18.1 752 59.0 .123 From this table it would seem that there was little or no difference in accuracy in sights ranging from 300 to 000 meters in length, while for sights less than 300 meters a much smaller degree of accuracy was obtained. Such a conclusion, however, must be greatly modified by the fact that very long sights are taken only when all conditions are favorable, while short sights are necessary when much wi-nd is blowing or when the air is "boiling," conditions which are both unfavorable for accuracy. The shortest average length of course in any closed line was 92.4 meters, and the greatest average length 704.0 meters. It is not likely, however, that sights as long as 500 or 600 meters could be taken advantageously anywhere except in atmosphere as clear as that of the Southwest. With the idea of determining to what extent the accuracy of the work was increased by compensation of errors iu the longer lines, the whole number of lines was divided, with reference to the number of courses in each line, into two classes, as shown in the following table: Number of lines. ■•IF Meiers. 238, 732. 2 587, 783. 7 nti^r^^f courses per line, 9.7 30.9 Average error in length of distance on course. closing [equals lin- Average err per kiromete or on closing, r of line run. In azimuth. In elevation. 47 2[eters. 348. 683 404.9 784 1 28 47 Meters. 0.165 .107 118 820, 515. 9 18.1 386.2 752 59.0 .123 This table shows that both the azimuth error and the error in elevation were more affected by the number of courses per line than was the error iu distance, but that the accuracy of all increased with the number of courses per line. Finally, to show how the character of the work was affected by practice on the part of the observers, the following table was arranged, comparing the lines run in 1892 with those run in 1893 : Tear. Aggregate Average length of lines. Average length of of courses per line. Average distance on closing equalslin- Average eiTor on closing, per kilometer of line run. of lines. lines. In azimuth. In elevation. 1892 81 37 118 Meters. 449,773,9 376, 742, Meters. 5,552,8 10,182.2 Meters. 341.5 457.8 16,3 22.2 697 829 1 18 35 Meters. 0.130 .116 826, 515, 9 7,004.3 386.2 18.1 752 59.6 .123 Most of the work during the two years was done by the same observers, with the same instruments and rods, and under practically the same general conditions, consequently it is fair to assume that all differences in the character of the work during the two years were the direct UNITED STATES AND MEXir'AN BOUNDARY. 159 result of practice and experionco on the part of the observers. Tlie table shows that both the average length of the lines and that of the courses was greatly increased iu 1893, as was also the accuracy in distance, aziinutli, and elevation — notably iu azimuth. A study of the preceding tables shows that the average azimuth error, on closing, per kilometer of line run, varied approximately inversely as the product of the S(iuare root of the average number of courses .per line into the average length per course; or, denoting these quantities by e, N', and /, respectively, we have v varies as 1 I v/ -N, which is the theoretical law of variation, and becomes 1/ v/N when the courses are of enual length. Theoretically this last ratio should also be true for the error in distance on closing; but in practice this w:is not found to be the case, the variation being nnich more gradual, indicating the existence of constant errors, which neutralized, to a considerable extent, the theoretical compensation. Since the conclusion of the survey it has been shown by Mr. L. S. Smith, C. E., now assistant profes.sor of topographical engineering in the University of Wisconsin, but in 1892-93 occupying the position of transitman on tliis survey, partly from observations taken during the progress of the survey aiul partly from others taken more recently (see Chapter X, Appendix, of the present report), that the constant error alluded to is very lai'gely due to the efiects of "differential refraction," i. e., the diflference in the amount of refract ion experienced by the upper and lower lines of sight, which difference varies with the season and with the hour of the e frequent very windy days, and the precipitous mountains often requiring vertical angles as high as 00'^ and incclndinu tlic possibility of resections, confirmed the selection of the transit as the only practicable instrument for this work. The level line, as a rule, followed the tangent lines of the boundary, taking elevations to secure a ])rofile and to furnish reference points for elevations in topographical work. When difficult mountains were encountered the level line went around and joined the tangent again on the further side, a transit profile being taken over the mountain. The level party was generally the first to quit work on account of the midday beat. The great heat and vibration of the atmosphere necessitated a cessation of work during tlic summer months from 10 a. m. to 3 p. m., and often longer. Great care was taken to secure as accurate work as possible. Sights were ordinarily limited to 100 meters and were restricted to 250 meters. They averaged about (50 meters. The level 168 UNITED STATES AND MEXICAN BOUNDARY. adjustments were tested daily, aud all possible care was taken to protect the bubble tube from the disturbiug effects of the heat. Two indepeudent readings were taken on each backsight and foresight; if these did not check within 1 millimeter, more settings of the target were made until such agreement was secured, the mean of the two being taken as correct. The levelman was required to check the final leading of the target on each sight. Each rodman kept a peg book for checking the levelman's computations. Each day's work was checked by a summation of backsights and foresights by both levelman and rodiiien. The level line as carried along the boundary gives the elevation at El Paso 2.67 meters less than the elevation assumed at starting. The assumed elevation was the mean of elevations given by the Southern Pacific Railway and the Atchison, Topeka and Santa Fe Railway, the former having been brought from San Francisco and the latter from St. Louis. Further details of the level work are given in the Report of the Commissioners under the head of topography. The measurement of the boundary line furnished monument distances, distances for the profile of the line, and points for the starting and closing of topographical lines. It was made by stadia for the whole distance. The length of sights varied from 100 to 300 meters, and averaged 214 meters. As a rule the length of sight was smallest toward midday, the vibration of the atmosphere already mentioned troubling during the summer for eight or nine hours of the day when on the plains, and stopping the work for four or five hours. This vibration was the greatest on sandy plains having little vegetation. Though very aggravating, it was not so excessive as the temperature and character of the country would lead one to expect. The slight humidity of the atmosphere probably modified its amount. Work would generaly stop when the amplitude of vibration reached 1 centimeter at a dis- tance of 200 meters, while at midday this amplitude would often be as much as IJ centimeters, and at times 2 centimeters at the distance mentioned. A peculiarity of the vibration of the air was its double character, or what might be called a primary and a secondary vibration. When this primary vibration had an amplitude of 1 centimeters and a rate of 30 per minute, at the same time would be remarked the secondary vibration, having an amplitude of 2 centimeters and a rate of 60 per minute. A double measurement of eacli distance was made, first as a foresight and then as a back- sight. Besides the profiles over mountains, profile points were often taken, in ravines or on ridges, by distance and vertical angle to assist the levelman. This measurement of the line used two of the rodmen. The third was occupied in giving topographical points for 200 meters on the Mexican side and adjacent points on the American side that could be taken to advantage. Incidental to this work there were also taken from the tangent slope angles on the plains observations for magnetic declination at intervals of about 2 kilometers (for resume of which see Report of the Commissioners under the head of topography), and intersections to and vertical angles on mountain peaks and ranges on each side of the zone of instrumental topography. Great care was taken to secure a true and accurate interval factor. At first frequent determinations were made, and afterwards at intervals, to make sure that there had occurred no change of magnitude due to accident or to lapse of time. One determination was made after the transit had been exposed to the heat of the day to see if this appeared to aft'ect its interval, but no difference was apparent. The method usually followed in testing the interval was for two observers to take two read- ings, each at intervals of 40 meters, on a ciirefully measured base line (corrected for inclination and for the temperature of the tape) 400 meters in length. The transit was placed at a distance beyond the end of the base line equal to its focal distance plus the distance from center of instru- ment to the objective (f + c). Occasional obvious errors of reading were rejected, and the interval factor was determined for each distance. Tlie mean of these was taken as the true factor, giving those of the observer who ordinarily used the transit double weight. After the first group of observations, when the newly determined factor differed but little from the previous ones (as was usually the case), the mean of the latter was given double the weight of the one just taken in obtaining the working factor. In all the determinations of the interval factor, made for the transit used in the measurement of the line, nearly 800 readings were taken, and the greatest deviation of any determination from the mean, during its twenty months of service, was less than 11000. UNITED STATES AND MEXICAN BOUNDARY. 169 Tables of distauces were made for the successive working interval factors in which the term /+ c entered, giving an easy and quick way of reducing the stadia reading to distance. As before stated, the belt of topography taken was 4 kilometers wide ou the American side of the line. The plan of work contemplated the instrninental location and determination of elevation of all topographical features that would appear ou maps drawn on a scale of 1/30000, with contours at vertical intervals of -0 meters. The tangeut lines iu their measured distances aud established elevations were taken as tlie basis of the topography. From them stadia lines were run in a general northward direction, from the stations of which secondary sights (giving azimuth, distance, and vertical angle) were taken on salient points of the terrene, and, covering in this way an advantageous area, the main line turned southward, closing again ou the tangent line. Each main line was a true transit line, each station being occupied by the transit. The zero of the vernier was kept always north, aud two sights for distance aud elevation were taken ou each course. To properly cover the terrene, spur lines were often run out from the main line, and where there was no indication of magnetic disturbance these spur lines were compass lines. Special topographic books were ordered, to contain the reduced held notes as well as the original entries. The latter consisted of the stations, azimuths, and stadia readings, vertical angles and heights of instrument (above the station), with explanatory notes, and with sketches showing the couliguration of the terrene, with the position of stations taken, and the location of all water, wood, grass, roads, trails, ranches, and towns. Often when crossing a plain with the tangent, transit, and level line, the second transit man would form a detached camp with his men in the mountain range ahead or in the one just left, while in wide areas of mountains all the instrument men would work on to]K)graphy to obviate too great a separation of camps. The vibration of the air interfering with observations much less in the mountains than on the plains, a greater accuracy and less interference with the hours of wofk were possible. It should be stated that the degree of accuracy of the work was reduced by the necessity of constant progress unless absolutely prevented by hard storms. It was the rule that field work should continue in storms as long as it was possible for the stadia men to hold up their rods in the wind. The notes were reduced in the field, and then sent to the oflBce for plotting. The reductions were made partly by a computer in the party and partly by the engineers on stormy days, during the midday cessation of instrument work, and evenings. Stadia readings were reduced to dis- tances and these to horizontal and vertical components, elevations of instrument and elevations of all stations were obtained, and the latitudes and departures of all closed lines with the circuit of elevatious were computed. The maximum allowable error of closing in distance was 1/300, aud iu elevation 1 decimeter per kilometer per degree of vertical angle; distances and elevations on the tangent lines were assumed correct in these computations. For computing the elevation of stations on closed lines a formula was devised which, by taking advantage of the two readings on each course, eliminated the correction for curvature and refraction. The derivation of the formula is as follows: Let the elevation of Station A (already known) be e, the H. I. there be a, and the vertical component of the reading on the next station be m. Let the elevation of this next station, B (to be determined), be x, its H. I. then be 6, and the vertical component of the reading back to Station A be n. Represent the correction for curvature and refraction by c; m aud n are positive or negative quantities according as B is higher or lower than A. The following equations, then, are derived: 1. x=e+aJt-m-\-c (by F. S. from A); 2. .v=e-\-n—c—h (by B. S. from B); whence: 3. 2x=2e-\-in-{-n-\-a—h (by adding 1 and '^)■, or: 4. .r=e + J (rt+)H + ji — 6). Equation 4 gives the formula as used, fi'om which the term e has disappeared. Errors due to the instrument being in not perfect adjustment, or to heat aflectiug tiie bubble tube or other portions of the transit (which is often (juite troublesome), being both errors of a character similar to that due to curvature in their mathematical effects, are likewise eliminated. Conseijuently the S. Doc. 247 15 170 UNITED STATES AND MEXICAN BOUNDARY. only errors entering the result are those of observation, and nonvertical rod, and sudden changes in refraction, which the use of this formula reduces by half; or, if large, such errors are detected m the process of reduction, and the erroneous sight is corrected in the held by another observation on the course in questioa. The average error of closing before the adoption of the formula was more than half greater than after its use. After completing the computation of the elevations of the stations ou the closed line in this way the discrepancy in elevations on closiug ou the tangent was distributed uniformly backward along the line. Errors in closing of latitude and departure were also uniformly distributed. The roads and trails of the country which this expedition followed were, outside of the zone of topography, and occasional short distances iuside the zone, located by taking the azimuth of successive courses with a prismatic compass, and the distances by counting a horse's steps of known interval, both the initial and final points of the meander being iustrumentally located. In the Dog Spring, Guadalupe, and Perilla mountains the greater part of the topography was taken by intersections instead of by stadia. This method was used because it shortened the time of field work, and it was made practicable by the occurrence in these places of a few peaks commanding the whole region taken. Stations on these peaks were located by intersection from the tangent line and from each other, and at these stations transitmen had their positions. An engineer with a flagman (both mounted whenever possible) would traverse an advantageous area, the flagman signaling at each salient point of the terrene, while the engineer made a contour sketch of the region, giving the located points, with their designating numbers, and recording the time of each signal. At the same time two transitmen occupied two advantageous positions ou commanding peaks, and upon each signal from the flagman took simultaneous observations upon his vertical flag, recording the azimuth, vertical angle, and time of each observation. At the close of each day's work each recorded observation of each transitman was numbered to cori-espond to the engineer's record, the time entry serving as a check in numbering. In the office each located point was plotted from the transitmen's stations according to the field record, and the distance from each station to each point was measured. From this distance and the corresponding vertical angle recorded the vertical component was computed; this, when corrected for curvature and refraction, was applied to the known elevation of the station, whence was derived the elevation of the located point. There being two observations on each point, comparison could be made. Eighty per cent of the points so located checked within less than 3 meters, even when the sights were 10 or 12 kilometers long. Of those not agreeing, the true elevation was indicated by reference to the contoured sketch. It was the intention in such intersection work to use aneroid barometers for securing eleva- tions if it was found that satisfactory results could be obtained. With this in view, one Cassella and two Queen & Co.'s compensated barometers were read ou the intersection work in the Dog Mountains just described. One of them was placed at a transit station and ten-minute readings taken to show the atmospheric fluctuations during the day; the other two were carried by the engineer and read at each toiiographical point. Tiie barometers were compared both before and after the work, and these readings also were recorded. The readings of each of the two observed barometers, as modified by these compared readings, were considered with reference to the readings of the stationary barometer; and the resulting differences (reduced by Guyot's Laplace's formula, as given by Williamson, to meters) gave the barometric differences of elevation. From these, knowing the elevation of the stationary barometer, the barometric elevations of the topographical points were determined. All care was taken to obtain, if possible, satisfactory results; yet the two observed barome- ters at times differed from each other at the same station as much as 20 meters, and both differed often from the iustrumentally determined elevations to a fatal degree, which at times amounted to 40 meters. From the Colorado Eiver eastward along the boundary for a distance of 300 kilometers the country is quite inaccessible, is almost uninhabited (having one ranch within 30 kilometers of the line on the American side), and is a true desert, having but five watering places, and some of these of limited capacity. This being such a wilderness, and offering many obstacles to the usual rate of progress, it was determined to modify the plans so as to further expedite field work. UNITED STATES AND MEXICAN BOUNDARY. 171 The method followed in the field work was the same as on previous work in all particulars, except for the surface irregularities of the outer 3 kilometers of the topographical belt. In this area flags were placed ou all tlie prominent peaks and ridges, and the location and elevation of these points were taken by the transit man from the boundary line. The second transit mau occupied the positions of these flags, and took azimuths and vertical angles on all flags in sight, thus covering the terrene with a network of location angles. At the same time he located other important topographical points by resection, where possible, but more often by stadia, and made a contour sketch showing the details of the whole terrene, the located flags furnishing the accurate groundwork for the whole. This method of field work suggests that followed in the mapping. The numerous flag locations furnished the salient points, the resections and stadia locations gave other accurately determined locations and elevations, and the minor details were tilled in from the field sketches. The results proved the wisdom of the plan. Less expeditious advancement would fre(]uently have caused serious complications. At one time a threatened failure of water was only averted by an arduous and successful search for natural tanks in the Cerro Cabeza Prieta, and by good fortune in developing the supply of the Tule Wells. As it was, the survey was enabled to successfully cross the deserts and secure its topography in as great detail as the character of the county warrants. The following table gives a general statement of the topographical work on this survey from the Rio Grande to the Pacific Ocean : Section. Detached lines. Transit. Compass. Number sights. Distance measured. tjn^r lines. Num- ber ^Ce linitr courses. Num. li^nfa. Num- ber courses. Length lints. courses. Rio Grande to ouc hundred and eleventh meridian. . . One hundred and eleventh meridian to Colorado 2,388 1,882 798 481, 963 377,426 226,467 201. 83 200.55 283.79 133 104 29 714 487 137 210, 499 134, 316 64,200 295 276 469 51 523 399 181,537 141, 233 78, 759 347 354 461 Colorado River to Pacific Total 5,068 1,085,856 214.26 266 1,338 409,015 306 91 1 1,093 401, 529 367 Section. Cloaefl lines. Sights other than turning points. | Stadia. Topographical inter- section. Mountain intersec- tion. 1 Nnra- b.-r lines. Num- ber Length Average length Number of sights. tjn^^r Points located. age length. Points located. Approxi- age length. Rio Grande to one hundred and eleventh meridi.nn 13,810 8,743 4,500 333 346 386 1,294 1,190 3,200 2,800 1,600 1,170 1,200 415 16, 000 25,000 30,000 One hundred and eleventh Tueridian to Colorado Colorado to Pacific Ocean Total 118 ' ' ' ' 1 SUMMATION. Kind of location. Number. terjr Total length. Stadia sights 36,692 2,523 2,785 329 3,000 22, 000 12,083,254 Topographical intersections Total 42, 000 172 UNITED 8TATES AND MEXICAN BOUNDARY. On the closed lines the average error of azimuth per course is 23". The average error in the closing by latitudes and departures is 1/752. A further discussion of tlic results obtained is found in the Report of the Commissioners under the head of topography. Concerning the elevations on closed lines it is to be noted tliat the sum total of the vertical components on the aggregate length of lines of 820,516 meters is 38,091 meters, giving as the average vertical angle 2° 38' 10". The average error in closing in elevation is 1/374 of the vertical component, or 0.123 meters per kilometer of distance. By grouping the lines according to their average vertical angle and plotting the corresponding errors in elevation of closing (expressed in meters per kilometer) I was enabled to draw tlie mean curve. If 6 represents the average vertical anele expressed in degrees, the equation of this curve is 3Q(^^;^;-^) + ^ Theoretically the error should vary as the tangent of the angle only. The presence of S itself in the equation is due, I believe, to the fact that in practice rodnien will not hold the stadia rod vertical even with the aid of a plumb line, the tendency being to hold it perpendicular to the general slope, and so introducing an error varying with the inclination of the line of sight to the horizontal. More favorable conditions in the field would change the constants of the equation and give a smaller probable error of elevation. These conditions would be secured by not working in very windy weather nor when the heat vibrations of the air are troublesome; by using transits whose vertical circles will read to a fraction of minute and whose stadia wires are as fine as possible and yet plainly visible. A reconnoissance from Yuma eastward along the boundary, in February, 1893, developed the fact that eastward from old Monument No. II (204), near the Colorado River, there was no authentic mark on the line until old Monument No. VI (175), about 103 kilometers distant, was reached. As both these monuments are on plains, with three ranges of mountains between, it became neces- sary, before the survey could begin from the west, to establish a point on tlie westernmost range (the Tinajas Mountains) on a line connecting the two monuments Just mentioned. Preparation was made at Yuma for this expedition, which proved to be the most severe on the survey. Nearly half of the men deserted, when opportunity offered, on account of the arduous duties and forbidding prospect, and i)raise is due the engineers and those of the rodmeu and teamsters who helped me to acconiiilisli the purpose of the expedition and continued with the work. All my party except one hcliolropeiium at Monument No. II (204) left Yuma by wagon train, following the Gila River eastward for 50 kilometers, then turning southward along the east foot of the Gila Range. The fii'st water was reached at Tinajas Altas, 00 kilometers from the river. Seven kilometers southeast of this jdace two engineers with rodmen were left to occupy with their instruments stations on the Tinajas and Lechuguilla Mountains. With the wagon train I continued eastward 33 kilometers across the Lechuguilla Desert to the next water, at Tule Wells in the Tule Mountains, the easternmost of the three ranges. From this place I sent ahead by pack train a heliotropeman across the Tule Desert (73 kilometers) to the next water, at Agua Dulce, about 7 kilometers from Monument VI (175). The plan followed for establishing this line was for the heliotropeman at Monument II (204) to show a constant light westward along the line, the engineers to work to the line by successive approximations. Fortunately the middle range (the Lechuguilla Mountains) proved to be so low at the line that observers could see over it, and the Tule and Tinajas Mountains were the only ranges it was necessary to occupy. As an initiative I assumed a point on the Tule Mountains as near the line as I could guess, and from it showed a heliotrope to the Tinajas Mouutalns. There the engineer, by successive trials with his transit, lined in between my light and that at Monument No. II (204). Then he showed his heliotroi»e toward me and 1 lined in between him and Monument No. VI (175). By repeating this operation the line was continually approached. The particular difficulty of the work will be realized when the character of the mountains in which these successive approximations were made is known. The Tinajas Mountains are a range excessively rugged and precipitous, about 4 kilometers wide, from 300 to 400 meters in elevation above the desert, and composed of numerous i)arallel ridges that had to be scaled in succession. Old MoNi ment No I, on MENTO No. I, EX EL PaciEICO. UMTED STATES AND MEXICAN BOUNDARY. 173 The Tule Mountains are of much the same character, except that they are composed more of a succession of peaks than of ridges and are about 12 kilometers wide. Added to this there were numerous windstorms raising a dust that often obscured the heliotropes at the distance of about 70 kilometers, and clouds and thunderstorms farther complicated operations. The rodmen detailed to assist me in this work gave out after two or three days, leaviug the engineers alone to make the observations and effect all the details of the work unaided. By unremitting effort and labor the purpose was finally accomplished, the successive camps called in, and the party returned to Yuma. When on the regular survey this line was carried tlirongli with a Fauth theodolite and reduction made to the true line, it was found that the point set in the Tinajas Mouutaius was less than a meter (0.87) from the true line connecting the two monuments. My tirst duty is last accomplished. With pleasure I commend the work of Mr. Li S. Smith, of Wisconsin, Mr. r. D. Cunningham, of Tennessee, Mr. James Page, of Maryland, and Mr. A. F. Woolley, jr., of Georgia, transitmeu, and of Mr. P. D. Cunningham, of Tennessee, Mr. S. W. Speiermann, of Utah Territory, and Mr. Ernst Franke, of Colorado, levelmen. The courage, efficiency, and faithfulness of these engineers on the topographical work of this survey deserve especial mention. CHAPTER ^ I. OLD MONUMENTS. Under the treaties of 1848 and 1853 the boundary was marked by monuments of stone and iron. In the process of their erection the line was divided into three sections, the monuments being numbered in each section independently. The numbers appeared only on the maps and were never placed on the monuments themselves. The first section comprised the Southern California boundary, extending from the Pacific Ocean to the Colorado River, a distance of about 141 miles, and was marked l)y 6 monuments. The second section was the azimuth line from the Colorado River to the one hundred and eleventh meridian — 234.3 miles — with 19 monuments. The third section was the line from the Rio Grande to the one hundred and eleventh meridian, and includes the boundary along parallel 31° 47', the meridian, and the; parallel of 31° 20'. This section was marked with 27 monuments according to the maps of the American Commissioner, and 28 as shown on those of the Mexican. In detail these old monuments were as follows: Beginning at the initial point of the survey, at the Pacific Ocean, the first monument was located near the coast and, in accordance with the treaty, one marine league south of San Diego Bay. This was an elaborate structure of marble, made in New York and brought to this coast by a naval vessel, landed in the bay, and hauled on wagons to its destination. It consisted of a pedestal and shaft of white marble, the whole 10 feet high, and resting on a foundation of brick laid in mortar. The cutting and polishing, as well as the inscriptions, were finely executed. Its dimensions and inscriptions were as follows: Pedestal, including base, dado, and surbase, 5 feet 6 inches high; the dado 3 feet 2^ inches square. The shaft was a pyramidal stone 10 feet 6 inches high, terminating in an acorn-shaped ornamental top. On the dado were inscriptions as follows: North side: "Direction of the line," with carved arrow above, "United States of America" on a raised shield, a laurel wreath below. On south side similar decorations, with inscription in Spanish, "Direcion de la Linea," "Republica Mexicana." On east side: "North latitude 32° 31' 59.58," longitude 7'' 48'" 21. 1» west of Greenwich, as determined by Maj. Wm. H. Emory on the part of the United States and Jose Sala/.ar Ylarregui on the part of Mexico." On the west side: [uitialpoiiitofbonnilary lietween I'mito inicial tie limite entre tlie Uniti'd States aud Mexico, es- Mexico ylos Estados Uuidos, fi.jado tablislied by the Joint Commission i>or la Comision Unlda 10 de Octu- lOtU October, A. D. 1849, agreeably bre, A. D. 1849, segun el Tratado to the treaty dated at the City of coucluida en la Ciudad de Guada- Guiidalupe Hid.-ilgo February 2, A. lupe Hidalgo el 2 de Febrero, A. D. D. 1848. .John B. Weller, IT. S. Com- 1848. Pedro Garcia Conde, Coml- missioner. Andrew B. Gray, IT. S. sionado Mexicaua. .lose Salazar Surveyor. Ylarregui, Agrimensor Mexicana. 174 UNITED STATES AND MEXICAN BOUNDARY. This monument had been so badly mutilated by visitors that some of the inscriptions had become illegible and the proportions of the stones seriously changed. Should the work of destruction have continued, the entire monument would eventually have disappeared. The other 5 monuments of this section were of cast iron and composed of thin jjlates riveted together. They consisted of a base, an inverted shallow box of iron, 3 feet square, a shaft 2 feet square at base, 1 foot at top, 6 feet high, and terminating in a pyramid. The inscriptions found on the perfect monuments of this series wei-e as follows : North side, " Direction of the Lin(%'' "United States of America," also an arrow and shield. South side, arrow and shield, "Direcion de la Linea," " Republica Mexicana." East face, " Boundary between the United States and Mexico agreeably to the treaty of Guadalupe Hidalgo of Feb. 2, A. D. 1818." West face, " Limite entre Mexico y los Estados Unidos conforme el tratado de Guadalupe Hidalgo del \i de Febrero A. D. 1848." These monuments were located, respectively, as follows: No. II, about 5 miles east of the marble monument, in the valley of the Tijuana River, where the Mexican towu of that name has since been built. No. Ill, nearly 8 miles farther east, on Otay mesa, at the foot of the Coast Range. A long interval, including the whole mountain region, occurs before reaching No. IV on the west side of New River, in the middle of the Colorado Desert, distant from No. Ill about S2.'2 miles. No. V on the east side of New River, 1.7 miles beyond No. lY. No. VI on the mesa south of Pilot Knob Mountain, near the Colorado, 43.5 miles east jpf No. V. Of the 5 iro7i monuments 3 had been destroyed, Nos. IV and V remaining in good condi tion, with the exception of their foundations, which were insecure. The latter apparently had been constructed of poles laid on the surface of the ground, and the monument fastened down by means of 4 iron rods passing through the base and anchored to pieces of wood embedded in the sand below. Had the sand been confined the method would have answered well. The sand had, however, drifted from beneath the bed of poles, and the monuments gradually settled, the ends of the bolts protruding several inches above the base. The iron bases, somewhat broken, of the 3 destroyed monuments were found in their proper places. These were resting on masonry foundations, but the superstructures had entirely disappeared. Of the 19 monuments shown on the maps of the second section, but 11 were found by our surveying parties; the other 8, if put up, had totally disappeared. All the monuments on this section, except No. II, located on the mesa east of the Colorado River Vsilley, were rude heaps of stone fragments, thrown together without mortar, and unprovided with inscription plates of any kind. Monument No. I, of this section, was shown on the map to have been located near the river bank 20 miles south of the junction of the Gila and Colorado rivers, but no trace of it could be found. No. II is an iron monunient which formerly marked an important reference point near the junction of the Gila and Colorado rivers, but had been moved to the new line established to comply with the terms of the Gadsden treaty. This monument stands on the edge of the mesa overlooking the Colorado Valley, and 2.7 miles east of that river. It is pyramidal in shape, 8 feet high, 2 feet G inches square at bottom, 1 foot 3 inches square at top, with a base 4 feet square, and, like those on the southern California boundary, is composed of thin cast-iron plates riveted together. Its foundation, like the others, was found defective, and is now replaced by masonry. Following the line eastward, Nos. Ill, IV, and V could not be found. It is possible they were never erected, as no trace of them exists, and it is hardly presumable that in this part of the desert, where a human being seldom passes, man's agency could have removed them. No. VI, a rude pile of stones, was found 101.2 miles east of No. II. Nos. VII and VIII, both originally located near the important Quitoba-quita Springs, were also missing. These had undoubtedly been destroyed by unknown persons and for unknown reasons. UNITED STATES AND MEXICAN BOUNDARY. 175 Nos. IX and X were found — IX, 19.5 miles east of No. VI, and near the present settlement of Sonoyta; No. X, 14.6 miles east of IX, on the western spur of the Nariz Mountains. No. XI was missing. No. XII, on the eastern spur of the Nariz, was identified, and is 4.5 mUes east of No. X. No. XIII, 28.9 miles east of No. XII, located near the intersection of the road and boundary, and also near a precipitous rock, was so obscured by mesquite bushes that it was found with much difficulty. No. XIV was situated in the Moreno Mountains, a considerable group of hills, 12.3 miles farther east. No. XV, 17.1 miles eastward, where the line crosses the crest of the Pozo Verde Mountains, the southern extremity of the Baboquivari Range. This monument affords a conspicuous mark from both directions. No. XVI, 9.2 miles beyond, occupies a position on a hill in the rolling country near the western slope of the Fresnal Mountain. No. XVII, 2.6 miles from No. XVI, occupies the summit of the Fresnal and overlooks the adjoining country far to the east and west. Eighteen miles beyond, on one of the most rugged of the Pajarito Mountains, No. XVIII was located, the last authentic monument found on this section of the boundary. A small pile of rocks seemed to indicate the location of No. XIX on a high ridge near the angle at the Eastern end of this section, but was not accepted as a monument. The remaining section of the boundary was marked, as shown by the official map on file at Washington, with 27 monuments, while upon the Mexican official map there are 28. The discrepancy occurs on that part of the line along parallel 31^ 47'. The joint report of 1856 states that this line was marked by 10 monuments; the American copy of the map shows but 8, and the Mexican copy 9. Considerable confusion and uncertainty was occasioned by these differences. These monuments were numbered on the maps from the Rio Grande westward, the last number, 27, upon the American map, being at the intersection of parallel 31^ 20' with the azimuth line, at the one hundred and eleventh meridian as shown on that map. The initial monument of this line stands on the west bank ot the Rio Grande, and at the date of our survey, 1892, was 172.6 meters from the center of the stream. When the location was made this distance was 71.04 meters, the channel of the river having moved 101.56 meters eastward since the location of the monument in 1855. The monument was built of cut stone, 12 feet high, 5 feet square at base, 2 feet 6 inches square at top, and was found in fixir condition. The lower courses were somewhat disintegrated by the action of water, due to floods in the river or the wash from heavy rains pouring down the adjacent hillside. The following inscriptions were upon this monument: (hi till' north: On the south : V. S. R. M. Boundary accortling Limite cnnlorme to the treaty Ai tiatado 30 of Deiember 30 de Deciembre de 1853. 1853. East side: IVesI side: William Helmsley Emory Jose Salazar Ilairegiii American Commissioner. Comissionado Mexicana. Nos. 2 and 3 were found in good condition. No. 2 was 7111 meters west of No. 1, and located on the highest point where the line crosses the Mulero Mountains. No. 3 was 3.2 miles from the river at the edge of the wide mesa, which extends westward beyond the range of vision. These two monuments were pyramidal in shape, 5 feet siiuare at base, and built of rubble masonry, plastered on the surface with lime mortar, which had scaled oft" considerably. They were without inscriptions, but their height, 12 feet, and white color made them very conspicuous as boundary marks. 17G UNITED STATES AND MEXICAN BOUNDARY. The next momimeut on this line was found 37.27 miles west of the river. It was much broken down, but from its shape and the several inscription stones found among- the ruins it was undoubt- edly erected as one of the marks of the boundary. It does not appear on the Emory map, but its approximate position is shown on the Mexican map, and accounts for the discrepancy in the number of monuments upon the two maps. The next monument was about 50 miles from the river. (This, like the preceding, does not appear on the Emory map, but one, no trace of which was discovered, is shown about 4\ miles to the east, on the summit of " Monument Mountain." The line falls to the south of this mountain, which, on account of its shape, we have called The Camel.) The monument was in bad condition, only about two-thirds of the original structure being in place. Plates of cut limestone, about 12 by 16 inches, contained the following inscriptions: On north side, the letters "U. S.;" on south side, "R. M. ;" on east, "W. H. E.""A. C.;" on west, " J. S. I." "C. M.," all well cut and perfect. It was built of irreg- ular and small fragments of stone laid partly in mud and partly in lime mortar. In dimensions it measured 5 feet G inches square at base, with a batter of about one in ten. Its height was originally 12 feet. From this point the wide valley westward, in which lie the Palomas lakes, is overlooked. Thirteen and one-third miles farther west, and north of Lake Palomas, was found No. 5 of Emory's map. It was of the same general character as the former, including inscriptions, but in a more dilapidated condition. The next monument — iSTo. 6 of Emory's map — was found 8,2 miles west of No. 5, on the summit of the foothills south of the Tres Hermanas Mountains. It was of the same general character as the others and nearly demolished. Thirteen and four tenths miles farther west, and 2 miles south of the fine Carrizalillo Spring, Monument No. 7 of Euiory's map was found. This was in a demolished condition, though the base was well defined and the usual inscriptions, with one exception, were present. It was located on low ground, but near an old road, now little used, running south from the spring. East of this monument a distance of seven-tenths of a mile, and situated on a high ridge of the Carrizalillo Hills, was a square monument having vertical sides. This monument, being exactly on a line Joining Nos. C and 7, was believed to be a boundary mark, and the one necessary to complete the full number of ten reported by the joint commission of 185(5. It had )iot the ordinary characteristics of tlie otiiei- monuments and was without inscriptions. No. 8 of Emory's map, or No. of the Mexican map, and the tenth as actually found upon the line, marks the imi)ortant point which terminates the boundary along parallel 31° 47' and the beginning of the meridian section. It stands diagonally with reference to both lines, and is a flue cut-stone monument, in better preservation than the initial monument at the river. It was pro- vided with the same inscriptions and was substantially of the same dimensions. With the exception of its base and one stone of the lower course it required no repairs. Near the middle point of the meridian section, or about 15 miles south of the "corner," was found No. 9 of Emory's maji. This had been originally well constructed of rough stone laid in mud mortar, but was found in bad condition, the mud plaster having scaled oft" and many of the stones loosened. It had inscription plates of stone containing the initials "U. S.," "R. M.," " W. H. E.," and "-J. S.I." At the south extremity of the meridian line and the beginning of the boundary on parallel 31° 20' was an excellent cut-stone monument in nearly perfect condition. Its dimensions were the same as those of the monument at the upper corner, as were also the inscriptions. The section of the boundary along parallel 31° 20' was originally marked, according to the Emory ma])s, with 17 stone monuments, numbered from 11 to 27, inclu.sive. Piles of stones, some bearing monument characteristics, M'ere found at fifteen points approximating to those given on the maps. Those corresponding to the positions of Nos. 11 and 24 were not found. No. 12 was a rude pile of loose stones, 28.6 miles west of the corner monument, on the eastern foothills of the San Luis range. No. 13, 3.8 miles farther west, marked the highest ])oint where the line crosses this range, and the highest on the entire boundary. No. 14, 3.4 miles beyond No. 13 and just west of the San Luis Mountains, was located near the important San Luis Springs. 9. Old Monument between New Mexico AND Arizona. Antiguo Monumento entre Nuevo Mexico Y Arizona. UNITED STATES AND MEXICAN BOUNDARY. 177 No. 15, only 3 miles west of the latter, had been placed on a long, low ridge, which ha.s every appearance of being an ancient artificial dam. The next mounment, No. 10, 13.3 miles beyond No. 15, was iu the Guadalupe Canyon where the wagon road crosses the bouiidary. No. 17 was on the Hat west of and near the San Bernardino River. It had no characteristics of a boundary monument except its position. Only 189 meters beyond, on the brow of the mesa, was No. 18. Though more distinctive than No. 17, it was badly dilapidated. Three of the old inscription plates, in a broken condition, were present. The next monument. No. 19, 9.8 miles farther west, was found in a range of hills which extends west from the Perilla Mountains, and near a prominent feature of the landscape known as the " Niggerhead," a steep, rocky mountain, almost inaccessible. Between this monument and the next one. No. 20, a distance of 42.8 miles intervenes. This stands near the west bank of the San Pedro Itiver, and is the monument erected under Major Emory's direction. Near this river, and occupying a bold promontory on its eastern side, was found another monument. Its position was 25" of arc, or about one half mile south of tlie boundary. This monument was built by Senor Salazar, the Mexican commissioner, after failing to find the one previously erected by Major Emory, and which tlie present survey shows to have been placed about 3" north of the true latitude. It was agreed between Major Emory and Senor Salazar, as expressed in their report, that iu case both these monunnuits were found to exist, the one erected by the American commissioner would be adopted. The San Pedro Kiver usually carries an insignificant amount of water, but during the rainy season is sometimes so swollen as to render it impassable. Nearly 18 miles farther west, just beyond the Huachuca Mountains, a scattered ])ile of stones was found, which corresjtonded sufficiently well with the position of No. 21 to be accepted as the site of that monument. It was upon a broad, open mesa, which extends several miles along the boundary, and is interseitted at frequent intervals by deep ravines. Two and eight tenths miles beyond No. 21, on the west side of a ravine through which Hows during the rainy season one of the sources of the Santa Cruz Eiver, was a pile of stones, which was decided to be monument No. 22. It had few characteristics to indicate its mission besides location, which was considered authentic. No 23, 5.J miles farther west, was found on a ridge overlooking the main valley of the Santa Cruz on the east, and a fine, grassy region on the west, in which is located the small settlement of La Noria. To the westward rise the sharp, rugged Patagojiia Mountains, on the summit of which, some 5 miles distant, No. 24 is shown on Emory's map. No trace of this monument, however, could be found, the next one being No. 25, on the east side of the Santa Cruz River, where the boundary crosses this stream the second time after the latter has made its detour around the southern extremity of the Patagonia Mountains and taken a northerly course toward the Gila Valley. This monument was quite a large pile of stones, having regular form, but without inscriptions. It was distant from ^o. 23 14.7 miles. Five and six-tenths miles farther on, in the broken country beyond the Santa Cruz, No. 26 was found. It was originally placed near the highway leading south into Mexico, which here runs through a beautiful, though narrow, valley containing good water near the surface. In later years a railroad has been built through this valley from Benson to the Gulf of California, and the thriving town of Nogales has grown up here, spreading out on each side of the boundary. The old monument occupies about the middle point of the settlement. When found it was but a rude pile of stones, though its base seemed to have been carefully laid with square corners, and some attempts made toward shaping the structure in the Ibrm of a pyramid. Badly defaced inscription plates were present. A building on the American side covered one-half of this monument, the sidewalk and street beiug on Mexican soil. 178 UNITED STATES AND MEXICAN BOUNDARY. In reference to this subject the commissioners made a special report to the Department, and as the matter is considered important a copy of that communication is inserted : Department of State, International Uoundary Commission, United States and Mexico, Nogales, Ariz., Noremher 39, 1S92. Sir: The American members