REPORTS OF ASTRONOMICAL OBSERVATOKIES. <;25 



piece; apparatus for projecting' solar image; eight other fsuhsiUiary 

 pieces. 



{(1) Spectroscopes: one employing large TtrTUEKFURD grating; one 

 with small grating; one 2-prism spectroscope; ai>paratus tor using largo 

 ecpiatorial as collimator, «^'c. 



(e) Photometers and other subsidiary apparatus : A variety of tln-r- 

 uiopiles, used in connection with a Thompson reflecting galvanometer; 

 large Bunsen photometer; small i)ortable heliostat, &(•. 



(/) Chronograph : one of Bond's pattern, built by II A:\rnLET. 



{g) Clocks: two mean time; by HowAKU, both break-circuit: one 

 sidereal ; by Fiiodsiiam, break-circuit, 



{h) Chronometers : one mean time; by Fkodsham: one sidereal; 

 Feodsham, break-circuit. 



(/) Miscellaneous : One reflecting telescope of 0.]-inch aperture, spe- 

 cially used for obtaining an image projected any size without the em- 

 ployment of any enlarging lenses, ami a number of subsidiary pieces 

 for investigations in heat and light. Electric appliances for the distri- 

 bution of exact time, automatically aud continuously to points outside 

 the observator}'. 



The work of research during the past year has lain chielly in meas- 

 urements of the distribution of energy in the spectrum of the sun. The 

 routine work of the time service has been continucHl. 



WOKK proposed for THE COMINO YEAU(1S81): 



(1.) The redetermination of the solar constant. 



[2.) Eedetermiuation of the law of the distribution of energy in the 

 solar spectrum as it is observed after al)sorptiou by our terrestrial 

 atmosphere. 



(3.) Determination (for the first time) of the law of the absolute dis- 

 tribution of the solar energy, or in other words the construction of a 

 curve showing the distribution of the solar energy as it would appear 

 to an observer stationed outside of the eartli'S atmosphere. 



Professor Langlby is now absent witli a large party prosecuting Ins 

 investigations on the solar constant, on one of the ligh mountains in 

 Southern Xevada. 



Amherst, ]\rassachusetts. 



College Observatory. 



Longitude trom ^^^lshington, 18"' i\S E. 



Latitude, 42° 22' irV'.G K 



Director : W. C. Esty. 



Founded in 1857 as an annex to the College. 



S. Mis. 31 40 



