REPORT OF THE SECRETARY. 11 



structure, a number of briek piers required for the firm support of the 

 flelicate apparatus employed. 



lu connection with the construction of this building, I desire to ex- 

 press my thanks to Col. O. H. Ernst, U. S. Army, in charge of public 

 buildings and grounds, for the supervision rendered by his office of the 

 work of excavating, etc., for the necessary sewer and water connections. 



The principal instrument consists of a siderostat constructed by Sir 

 Howard Grubb, of Dublin, Ireland, for the Smithsonian Institution, to 

 meet my special requirements. This arrived in March, 1890, and has been 

 mounted and put approximately into position for use. Another impor- 

 tant and novel instrument, a spectro- bolometer, was made under my 

 directions to meet new and unusual demands, and has also been received 

 and put in place. A third piece of apparatus, a special galvanometer, 

 also designed for the particular class of work in view, has been received ; 

 and the only considerable instrument now required to complete the out- 

 fit is a resistance box, which has been ordered and is expected from 

 London before the end of the calendar year. 



The siderostat is probably the largest and most powerful instrument 

 of its kind ever constructed. The spectro-bolometer is the largest in- 

 strument of its kind, and with this improved apparatus it is hoped that 

 interesting investigations begun several years ago, will be continued. 



Supplementary to these principal instruments is the Thaw collec- 

 tion of physical apparatus loaned b}^ the executors of the late Will- 

 iam Thaw, of Pittsburgh, and there are a few pieces of apparatus, the 

 personal property of the Secretary, so that at the close of the year it 

 might be said that the Institution was in possession of the nucleus of 

 a modern astrophysical laboratory. With this apparatus temporarily 

 mounted, researches have already begun, and one of a scientific and 

 economic character upon " The Cheapest Form of Light " has been the 

 subject of a communication to the National Academy of Sciences. This 

 work is mentioned as indicating my intention to give greater place to 

 one of the chief objects of the Institution, the direct addition to knowl- 

 edge by original research, — which, at least as regards the physical 

 sciences, has received comparatively little attention since the time of 

 Professor Henry. 



The prospects of renewed contributions to physical science by the 

 Institution in the field of original research are happily now better than 

 for many years past. The late Dr. Jerome H. Kidder, formerly an offi- 

 cer of the U. S. Navy, and later attached to the U. S. Fish Commission 

 and to the Smithsonian Institution, had bequeathed to the Institution, 

 in a wijl made several years ago, the sum of SlO,tiOO to be employed for 

 biological researches. Dr. Kidder, having become especially interested 

 in the x)roposed astro-physical observatory, had the intention of trans- 

 ferring this bequest, or at least a portion of it, to such an end, and he 

 even ordered that a codicil giving $5,000 to the Institution for an astro- 

 physical observatory should be added to his will, but he was stricken 



