REPORT OF THE SECRETARY. 39 



placed in some more distant position, and it has been determined to 

 send them to the Tortugas, a group of islands within the Gulf of 

 Mexico, at which the United States coast survey has also a tidal 

 station. A single instrument, however, is still to be kept in opera- 

 tion at the observatory to record the changes in declination and to 

 exhibit the perturbations connected with the appearance of the 

 aurora borealis. 



Exchanges. — The general system of international exchange, which has 

 been the subject of so much attention heretofore, continues to increase 

 in magnitude and importance. By reference to the special report on 

 this subject, it will be seen that the operations have been more exten- 

 sive in 1859 than during any preceding year. The facilities afforded to 

 the operations of the Institution in the department of exchanges and 

 of natural history by various transportation express companies, as 

 referred to in the preceding reports, have been continued throughout 

 the year. The steamers of the North German Lloyd have carried a 

 large amount of freight for the Institution, free of charge, between 

 Bremen and New York, as promised by their directors, at the in- 

 stance of Mr. Schleiden, minister from Bremen, resident in Wash- 

 ington. The steamer lines to California, consisting of the United 

 .States Mail Co., M. 0. Roberts, President; the Panama Railroad 

 Co., David Hoadley, president; and the Pacific Mail Co., W. H. 

 Davidge, president, transported a large amount of material for the 

 Institution up to the expiration of their mail contract in October, when 

 the North Atlantic Steamship Co., I. W. Raymond, president, re- 

 placed the United States Mail Co. in the line, which has since 

 continued the same favors. Mr. Bartlett, of New York, has offered 

 the use of his line of ships to the west coast of South America, and 

 the exchanges with Chili are now carried on chiefly through his ves- 

 sels. The steamer Isabel, Messrs. Mordecai & Co., of Charleston, 

 agents, has transported a number of packages for the Institution be- 

 tween Charleston and Key "West, free of charge, and Messrs. Russell, 

 Major & Waddel, army contractors of transportation to Utah, have also 

 rendered valuable service in this line. The Adams Express Co., through 

 Mr. Shoemaker, the superintendent of its southern division, has also 

 ^exhibited liberality in reducing its charges greatly on heavy freights, 

 and in carrying small parcels free of cost. It is difficult to esti- 

 mate the value to the Institution of all these services. They are 

 interesting as exhibiting a high appreciation of the mission and 

 .operations of the Institution, at the same time that they disclose a 



