560 



SCIENCE. 



[Vol. VI., No. 151. 



The services of the best American astronomers were 

 enlisted in collecting and reducing all astronomical 

 observations bearing on the matter. Measures were 

 at once taken for obtaining a different and better 

 class of results by transportation of chronometers on 

 the Cunard steamers between Liverpool and Boston. 

 This method so far superseded others, that it led to 

 the final adoption of the observatory at Cambridge, 

 Mass. , as the point of reference for all coast-survey 

 longitudes. Its director, Mr, W. C. Bond, also had 

 charge of all chronometers used in the Cunard 

 steamers. 



While this was in progress, other observers at Phil- 

 adelphia and elsewhere made and reduced observa- 

 tions of occultations and moon-culminations for the 

 same purpose. These observers did not belong to 

 the survey, but were paid small sums for copies of 

 their observations and reductions. By this means 

 the coast survey, under its enlightened head, assisted 

 in bringing forward many men who have since be- 

 come well known, but who were held back for lack 

 of pecuniary means and instruments, both of which 

 were supplied by the coast survey. 



The Morse telegraph had just come into use in 1844. 

 Its application to the purpose of determinations of 

 exact differences of longitude was suggested by Pro- 

 fessor Bache to the famous inventor before even the 

 success of the telegraph itself had been commonly 

 accepted as secure. Experiments were made in 1845 

 and 1846 as soon as lines were established, and in 

 1846 the first recorded observations were made be- 

 tween Washington and Philadelphia. The ease and 

 precision of the method attracted the attention of all 

 American astronomers, and all attempts at improv- 

 ing it were fostered by Professor Bache. Each year 

 brought improvements in the methods of observing 

 and recording, and greater precision and refinement 

 in the character of the results. First came the disk 

 of Professor Locke of Cincinnati ; next that was 

 improved upon, and the clock-beats by telegraph 

 rendered automatic by Prof. O. M. Mitchell, by which 

 an astronomical clock in Cincinnati was made to beat 

 and record its time both audibly and graphically in 

 other and many distant places at the same moment. 

 Finally the invention and perfecting of the ' chrono- 

 graph ' brought the whole to its present state of 

 perfection. As soon as the Atlantic cable became a 

 success, in 1866, it was at once employed by the coast 

 survey to obtain a precise difference of longitude 

 from Greenwich, and this was repeated at three dif- 

 ferent periods and by different cables and observers 

 in 1870 and in 1872, with an extreme discrepancy of 

 only five-hundredths of a second of time, leaving 

 nothing further to be desired. In 1852, on the death 

 of Assistant S. C. Walker, Prof. B, A. Gould suc- 

 ceeded him as assistant in charge of telegraphic lon- 

 gitudes at intervals until his resignation in 1868. 

 During this time the development of the method was 

 carried forward by him with his usual zeal and 

 energy. His last great work was the inception and 

 execution of the first telegraphic determination of 

 longitude from Greenwich through the cable, then 

 just laid, in the fall and winter of 1866. The diffi- 

 culties then encountered and overcome (much greater 

 than in any subsequent expedition) are fully detailed 

 in his elaborate report, printed as appendix No. 6 to 

 the coast-survey report for 1867. 



There have been printed between 1846 and 1884, 

 by the coast survey, 26 reports on astronomical 

 methods of determining longitude, 8 reports on chro- 



nometric methods, and 30 on telegraphic methods ; 

 in all, 64 papers, by Peirce, Walker, Bond, Gould, 

 and Hilgard, beiiig a larger mass of contributions to 

 our knowledge of this important practical and scien- 

 tific question than has been made by any other one 

 nation within the same period. 



This application of the telegraph to the determina- 

 tion of one of the two most important geographical 

 problems known to science has completely revolu- 

 tionized all previously known methods. It is in use 

 all over the civilized world, and is everywhere 

 known as 'the American method.' It was begun, 

 and has been brought to its present state of perfec- 

 tion, by the coast survey. 



The Gulf Stream. 



The exploration of this ' river in the ocean ' was 

 commenced in 1844, and has been continued ever 

 since under coast-survey direction. Apparatus was 

 used for obtaining temperatures at such depths as 

 could be obtained. In 1846 the separation of the 

 Gulf Stream into two branches was discovered, and 

 was dearly paid for by the loss of a brilliant officer 

 of the navy, brother of Professor Bache, who was 

 swept from the deck of the vessel he commanded in 

 a storm off the coast of North Carolina. The surveys 

 have been kept up and continued, as means have 

 been afforded, from that time to the present. 



The ingenuity and skill of the naval officers who 

 have been at different times attached to the survey 

 have resulted in improvements of means and methods, 

 until depths exceeding five miles have been reached ; 

 and it has been satisfactorily shown, that, under- 

 neath the warm surface-water of the Gulf of Mexico 

 and the Gulf Stream, the temperature of the water 

 steadily diminishes until it is nearly ice-cold at the 

 bottom. The inventive genius of Commanders Bart- 

 lett and Sigsbee, U.S.N,, while engaged in this duty 

 under Superintendent Patterson, has left little for 

 their successors to do but to follow in the way they 

 have marked out. 



Early in this work, or before 1850, the enlightened 

 and liberal view taken by Superintendent Bache, of 

 his obligations to science, led him to take up an appar- 

 ently different department of science in authorizing 

 dredging to be executed at great depths, that the 

 nature of the inhabitants of the deep sea might be 

 ascertained. This gave to America as a citizen one 

 of the most eminent naturalists of the world. The 

 late Prof. Louis Agassiz has left on record his state- 

 ment that his determination to become an American 

 citizen was decided on in consequence of the enlight- 

 ened liberality of Prof. A. D. Bache, superintendent 

 of the U. S. coast survey, in offering him the facili- 

 ties afforded by the surveying parties and vessels of 

 the work for conducting his investigations upon the 

 Atlantic and Gulf coasts. The magnificent models 

 of the bottom of the ocean in the Bay of North 

 America and the Gulf of Mexico, made under direc- 

 tion of Professor Hilgard, and that of the Caribbean 

 Sea by Commander Bartlett, U.S.N., are results of 

 the long-continued, earnest, and effective labors of 

 the various parties of the coast survey, and the in- 

 genious efforts of the officers of the navy, on coast- 

 survey service, who commanded them. 



Tides and currents. 

 Systematic observations of tides and currents were 

 begun in 1844 ; and in 1845 the very difficult problem 

 of tides in the Gulf of Mexico, where only one tide 



