38 EEPORT OF THE SECRETARY. 



past year, at the joint expense of the Coast Survey and the Smith- 

 sonian Institution. 



Laboratory. — The operations of the laboratory during the past year 

 have been principally confined to the examination and classification 

 of the minerals which have been collected at the Institution from 

 the various exploring expeditions, preparatory to a general distribu- 

 tion of the duplicates. This work has been intrusted to Mr. Thomas 

 Egleston, of New York. 



Facilities have been given to Professor Way, of London, for the 

 exhibition of his improved method of producing an intense light for 

 signals by means of the electrical deflagration of a stream of mer- 

 cury, and the Institution is indebted to this gentleman for the present 

 of a set of apparatus for exhibiting this light, and also of a powerful 

 galvanic battery. The apparatus of the laboratory has been increased 

 by a large Daniell's battery, consisting of fifty cylindrical copper 

 cells, each six inches in diameter and fourteen inches high, with 

 appropriate zinc elements of pure metal, procured expressly for the 

 purpose from Mr. Wharton, of Pennsylvania. 



Among the experiments which have been made, may be mentioned 

 a series by Dr. Craig, on the effects of the explosion of gunpoAvder 

 under pressure ; and another by the Secretary, on the burning of the 

 same substance in a vacuum, and in different gases. 



A series of researches was also commenced to determine more ac- 

 curately than has yet been done the expansion produced in a bar of 

 iron at the moment of magnetization of the metal by means of a gal- 

 vanic current. The opportunity was taken, with the consent of Pro- 

 fessor Bache, of making these experiments with the delicate instru- 

 ments which had previously been employed in determining the vary- 

 ing length under different temperatures of the measuring apparatus 

 of the base lines of the United States Coast Survey. 



It may also be stated that the Secretary was requested by the War 

 Department to report upon the practicability of employing balloons 

 for military purposes, and in accordance with this request the sev- 

 eral plans proposed by Mr. Lowe, of Philadelphia, and Mr. Helme, 

 of Providence, were examined and practically illustrated on the 

 Smithsonian grounds. 



It may not be improper in this connexion to state that a consider- 

 able portion of the time of the Secretary, during almost every year 

 since the beginning of the Institution, has been devoted to investiga- 



