[1] 



16 



gical purposes ; and Professor Espy, engaged under the act making this 

 appropriation, has been directed to co-operate with the Institution, in 

 promotion of the common object. Besides the aitl which we have re- 

 ceived from Professor Espy's knowledge of tliis subject, the general system 

 has been benefitted ia the use of instruments purchased by the surplus 

 of the appropriation, after paying the salary of the director and other 

 expenses. 



During the last year, Professor Espy has been engaged in a series of 

 interesting and valuable experiments, on the variations of temperature, 

 produced by a sudden change in the density of air. The results obtained 

 are interesting in addition to science, and directly applicable to meteoro- 

 logy. The experiments were made in one of the rooms of the Smithso- 

 nian Institution, and with articles of apparatus belonging to the collection 

 which constituted the liberal donation of Dr. Hare of Philadelphia. An 

 account of these investigations will be given to the Secretary of the 

 Navy in a report. 



It was mentioned in the last report that the Regents of the University 

 of the State of New York, in 1849, made a liberal appropriation of funds 

 for the re-organization of the meteorological system of observations, estab- 

 lished in 182-3, and that Dr. T. Romeyn Beck, and the Hon. Gideon HaAv- 

 ley, to whom the enterprise was entrusted, had adopted the forms and tb« 

 instruments, prepared under the direction of the Smithsonian Institution. 

 Another appropriation has been made for 18-50, and the system has beeji 

 carried, during the past year, into successful operation by Professor Guyot, 

 late of Neuchatel, in Switzerland. This gentleman, who has established 

 a wide reputation as a meteorological observer, by his labors in his ow'n 

 country, was recommended to Dr. Beck and Mr. Hawley, by this Institu- 

 tion, and employed by them to superintend the fitting up of the instru- 

 ments in their places, to instruct the observers in the minute details of 

 their duty, and to determine the topographical character and elevation 

 above the sea, of each station. 



The whole number of stations which have been established in the State 

 of New York is thirty-eight, including those which have been furnished 

 with instruments by the Smithsonian Institution, and the Adirondack station 

 by the liberality of Archibald Mclntyre, Esq., of Albany. This number 

 gives one station to twelve hundred and seventy square miles, or about 

 one in each square of thirty-five and a half miles on a side. These sta- 

 tions are at very different heights above the level of the sea. They were 

 selected in conference with Dr. Beck, Professor Guyot and myself. The 

 state is naturally divided into the following topographical regions, namely : 



1. The Southern or Maritime region. 



2. The Eastern, or region of the Highlands and Catskill mountains, with 



the valleys of the Hudson and Mohawk rivers. 



3. The Northern or region of the Adirondack mountains, isolated by the 



deep valleys of the Mohawk, Lake Cliamplain, the St, Lawrence 

 and Lake Ontario. 



4. The Western, or region of the western plateau, with the small lakes and 



sources of the rivers. 

 C). The region of the great lakes, Erie and Ontario. 



I regret to state that no efficient steps have as yet been taken to 

 organize the system of Massachusetts, for which an appropriation was 

 made by the legislature, at its last session. I have lately written to Go- 



