HISTORY OP THE WORK. xvii 



State, tht tabulated results of which Avere, for many years, published annually in 

 the Reports of the Regents. In preparing these tables, the prevailing direction 

 of the wind was computed in the then common though imperfect manner already 

 described, and the results were as chaotic as can well be imagined. I concluded 

 to try the new method upon them, and the results were published in tlie Regents' 

 Report for 1840, accompanied by a note from the Secretary of the Board, inviting 

 special attention to them. They were of the most satisfactory character, and 

 when mapped showed the course of the dominant current of air over the State, 

 with occasional deflections, dependent upon the geographical features of the 

 adjacent country, as clearly defined as the courses of the Hudson or the Mississippi 

 rivers. Encouraged by this, I undertook the task of collecting observations on 

 Avinds over the entire extent of the United States, which was then no easy matter, 

 as there were no such instrumentalities, to aid in the work, as are at present 

 accomplishing so much — the Smithsonian Institution and National Observatory 

 not being in existence, and the only collection of observations, covering any wide 

 extent of country, was that at the Surgeon General's Office in Washington. This 

 had been commenced under the Surgeon General, Dr. Lovell, in the year 1822, 

 and consisted of registers kept at dift'erent military posts, and others that had been 

 forwarded there at the request of the late Prof. James P. Espy, who was theu 

 connected with the office. None of the latter had been published, and of the 

 former, only those for the first nine years, and embracing only from eleven to 

 twenty posts, the number differing in dift'erent years. The rest was all in manu- 

 script, unpublished and unreduced. My attention was called to this collection by the 

 late Col. J. J. Abort, Chief of the Topographical Bureau, who, in 1839, invited me 

 to visit Washington for the purpose of inspecting it. Here I was not only allowed 

 free access to all the manuscript material in the office, which I spent several weeks 

 in examining and reducing, but when I left, I was permitted to take home with 

 me all the more valuable registers of Mr. Espy's collection, indeed all that I desired, 

 and to make the requisite computations from them there. Beyond what I thus 

 obtained, I was dependent almost solely on private correspondence for the means 

 of prosecuting my proposed work. 



" It was while engaged in slowly collecting material that, at a meeting of the 

 American x^ssociation of Geologists and Naturalists, held at New Haven, in 1845, 

 I was appointed a committee to report on the present state of our knowledge of 

 the winds of North America and the North Atlantic Ocean. This greatly en- 

 larged my field of labor, and as I knew that I could obtain material such as I 

 wanted from many European countries, I concluded to enlarge it still further, and 

 make it embrace the entire northern hemisphere. 



[For this purpose he availed himself of all the materials relative to meteorology 

 found in the libraries of New York, New Haven, Philadelphia, Princeton, and 

 Washington. As much of this material was unreduced, he was obliged to spend 

 a considerable portion of time at each of these places in the performance of this 

 work.] 



"Observations of the winds at several places in Persia, Syria, Palestine, and at 

 Constantinople, were kindly made at my request, for a year or two, by mission- 



c December, 1875. 



