Tribune Extras Lecture and Letter Series. 



the longitudes. An appropriation of $o2,500 has been 

 made to defray expenses. 



The French Commission before the Franco-Prussian 

 war recommended to the Bureau des Longitudes the 

 occupation <>f St. Paul's IMand, New- Amsterdam, Yoko- 

 hama, Tahiti. Noumea, Miscate, and Snrz. Since the 

 close of the war the subject has again been taken up, 

 the French Academv has applied to the <; ivernment 

 for aid, an. 1 under the head of "Public Instruction" 

 a provisional appropriation of S2 1.003 has been made 

 to he expended under the direct inn of a commission 

 whose head id Alplionse Martin. Lately this appropria- 

 tion has been increased, by one-half. 



Germany has decided to furnish four parties for helio- 

 meiiic observationsone in Japan or China, and the 

 others probably at Mauritius, Kerguelen's, ana Auckland 

 Islands. 



Oilier countries have male preparations on smaller 

 scales, even yew-South Wales granting $3,000, and, uuder 

 the direction of Mr. Russell, establishing three parties' 

 Ht Sydney. E len, and the third in the Blue Mountains, 

 about 5'i miles west from Sydney. Most of the European 

 nations sending parties to comparatively unknown re- 

 gions have attached a naturalist, and the expeditions in 

 this way will contribute to the natural sciences as well 

 as to astronomy. It would have been desirable to have 

 had a naturalist attached to the United States parties 

 bad the funds of the commission having the matter in 

 charge justified the necessary outlay. 



AMKKICAX PKKPARATIONS. 



In 1871 the United States Congress appointed a Com- 

 mission to expend sueli appropriations as might be made 

 for the observations of the transit of Venus. It consisted 

 uf the following members: Rear-Admiral B. F. Sands, 

 superintendent U. S. Naval Observatory; Prof. Joseph 

 Henrv, President National Academy of Sciences : Prof. 

 Benjamin IVirce, Superintendent U. 8. Coast Survey; 

 Prof. Simon Newcouib, and Prof. Win. Harkuess, U. S. 

 Naval Observatory. Tae Commission selected Admiral 

 Sands for chairman, and it is to his warm 

 sympathy with the cause of astronomical science, und to 

 his executive energy in properly bringing the matter 

 I'eforo our Government, that the thanks of American 

 fcienti-t.- are due; for with imvloouate provision for de- 

 fvayiii'-' the large outlay necessary, wo might have given 

 ica-on for the doubt of De Tocqueville which Prof. Tyn- 

 dall quoted to us : "The future will prove whether the 

 passion lor profound knowledge, so rare and so fai;h- 

 ful, can be born and developed so readily in demo- 

 cratic so-ieties as in aristocracies. As for me, I can 

 hardly believe it." The letter of Admiral Sands, 

 March 5, 1872, ask.ng for *150.000 to he expended in tnreo 

 annual HIM ailments of >.vi,otii> each, received the indorse- 

 ment ofthe Secretary of theNavy.and the ;ippropriations 

 asked were granted by Congress. It was resolved to 

 miiiii.y imth photography. and eye-observations of con- 

 tact, ami after discussion as to the various photo- 

 graphic methods proposed, it was decided to lorm 

 Hie linage of the sun on the sensitized 

 plate by means of a fixed photographic lens, five 

 inches in diameter, and having a focal length of about 

 forty feet, ivllecting the sun's light from one surface of 

 U plate ot gla.>s, I lie plate being moved by clock- Work, 

 BO that the rays of the sun, utter bring rellected from 

 the plate, will always strike the photographic lens in 

 lines parallel to the line connecting tlm ecu i IT of the 

 M-necting plate, the. center ot t le- li \ed len.-,, I lie cemer 

 of (he sensitized plate. To carry out tlm methods of 

 by the eye and car, it was resolved to pro- 



vide live-inch puuaforials, furnished with micrometers, 

 by which the distance between the two cusps of Venus 

 could be accurately measured, as Yonus entered uputi 

 and lefr the sun's disk. 



The principal work of carrying out the views of the 

 Commission has devolved upon those members of it 

 coniH-tcd with the Naval Observatory. After most of 

 the arrangements had been completed, th-re was a 

 change in the members of the Commission, caused by 

 the retirement of Admiral Sands from active dutv in tho 

 Naval Department on account of advanced age, and the 

 resignation of the Superintendent of the Coast Survey. 

 Both these gentlemen were retained as honorary mem- 

 bers, and R-ar-Admiral C. H. D.vvis. tho present Super- 

 intendent nf the Observatory, and Cipf. Patterson of 

 the Coast Survey, were added to the Commission. 

 OUK STATIONS AND INSTRUMENTS. 



Eight stations wen; selecte;!, an 1 so far as is now 

 known v.-ill be occupied ns follows: Vladivostok m 

 Siberia will be occupied by Prof. Hall of the N iv.il Ob- 

 servatory, with probably Mr. O. B. Wheeler of the Like 

 Survey as assistant. Pekin will be ocr'ii>i< <> by Prof. J. 

 Watson ot Ann Arbor. The Coast Survey party under 

 Prof. G. Davidson, who retains Mr. O. II. Pitt- 

 mann as first assistant, will occupy Nagasaki. 

 C.ipt. Kavmond of the United States iingineers 

 will occupy Crozot Island, with Lieut. Tilman 

 as assistant. L'eui. -Commanders Rvan and Train, U. 3. 

 N., will occupy Kergueleu's Islan I. Prof. Ilirkuessof 

 the Naval Observatory with Mr. L. Waldo of Columbia 

 College. N. Y., as assistant, will occupy Hohart Town. 

 Bluff Harbor, New-Zialand, will be occupied by Prof. 

 C. H. F. Peters of Hamilton College, N. Y.. assisted by 

 Lieur. Bass of the U. 8. Engineers. Mr. E. Smith with 

 Mr. Scott as assistant, both of the Coast Survey, 

 will occupy Chatham Island to tho extreme east. 

 Three photographers will be sent with each of the above 

 parties, and all the members of the various parties are 

 subject to the discipline of tho Navy during their ab- 

 sence. All of the Southern parties and one of I.he North- 

 ern are now in Washington in active preparation for the 

 transit. 



Eacli party is supplied with an equatorial, a transit 

 instrument so modeled as to be used as a zanith tel- 

 e.-eope at will, a clock, with chronograph, two tox 

 chronometers, a set of engineer's instruments, a mag- 

 netometer, a photographic outfit, a chest oi carpenter's 

 tools, suppli.-s, &C.; and \\ill carry with them three 

 wootieu huts, put up in sections, to be, pinned and 

 MMcwed together when they are needed by the observ- 

 ers. The instrumental outfit has boen designed and 

 constructed under tho immediate supervision of 

 Prof. Harkness, to whoso accurate knowledge 

 of the capabilities of portable instruments much of the 

 success ofthe expeditions \\ill be owing. Mr. Alvan 

 Clark constructed (he equatorial*, the pliotographi J ap- 

 p.iratus, and the optical parts of the trau.-it instru- 

 ments, of which the oilier p.irts were made by Stack- 

 pole Bros, of Nuw-York. Tuo clocks were made by E. 

 Howard ot lioston, and the chronometers by J. S. & D. 

 Negus of New- York. The magnetic instruments wore 

 made by Mr. Kahl'-rof Washington. 



The Southern parties will be conveyed to their destina- 

 tion by the U. S. third-rate sloop-of-\\ ar Swatar;., under 

 the command of Capt. Ralph Chandler. The s \\alara 

 usually c u i ic.s nine gn.is, but will carry but one. a Co- 

 pound J'arroi t , until she is through with the exp- li- 

 tmus. Shi is now lifting u at the Brooklyn Navy- 

 Yard. It i.-s e \pecled she \\ ill sail from New-York the 



last of May. Uor route will include the Capo ot Good 



