REPORT OF THE SECRETARY. 47 



and efficiently co-operated by publishing projections of the phases and 

 times of their occurrence in different parts of America. 



Under its auspices, and partly at its expense, an expedition was 

 inaugurated by Lieutenant G-illiss to observe the great eclipse of 1858 

 in Peru, from which data of value for the improvement of solar and 

 lunar tables were determined, besides facts of interest in regard to 

 the physical constitution of the sun. 



Assistance was also rendered to the expeditions under the direction 

 of the Coast Survey to observe the eclipse of July 18, 1860, one of 

 which was sent to Labrador, under the charge of Professor S. Alex- 

 ander, of New Jersey, and the other to Washington Territor}-, under 

 that of Lieutenant Gilliss. 



To these may be added an account of an instrument invented by 

 Rev. T. Hill, president of Harvard College, for the projection of 

 eclipses. 



Physics and chemistry. — The Institution has fostered these sciences 

 in many different ways; among others, by importing models of the 

 most improved articles of apparatus, and making them known to 

 scientific men through lectures and otherwise. 



It has instituted an extensive series of experiments on building 

 materials, particularly in reference to those employed by the gov- 

 ernment in the construction of the Capitol and other public edifices;; 

 also alike series on acoustics, as applied to public halls, and the prin- 

 ciples deduced from these were practically applied in the construction 

 of a model lecture-room. It has made a very extended series of ex- 

 periments on different substances employed for light-house illumina- 

 tion, from which has resulted the substitution of another material for 

 sperm oil, and the consequent annual saving of a large amount of 

 money to the government. 



In compliance with requests made by different departments of the 

 government and of Congress, particularly since the war, it has con- 

 ducted various series of investigations, principally in relation to ques- 

 tions involving mechanical, chemical, and physical principles, and has 

 made reports on subjects of this kind amounting, in the aggregate, 

 to several hundred. 



To facilitate researches, a laboratory has been established and kept 

 constantly in working condition, the privilege of using it having been 

 given to various competent persons for experimenting in different 

 branches of physical science. Just now it is occupied by Dr. Weth- 

 erill for the purpose of conducting a series of analyses of samples of 



