OBITUARY NOTICES. 
459 
or other radiating body and gave tables for use with the 
Arago-Davy actinometer. 
(19.) Applying the results of bis previous studies on 
temperature to the determination of the temperature of the 
moon, Ferrel was able to give us a close approximation to 
the condition of the moon’s surface and, again, a close ap¬ 
proximation to the average temperature of our whole atmos¬ 
phere at any elevation. 
(20.) 1885.—Ferrel’s studies in thermometry were made 
the basis of a special study on the whirled or sling psy- 
chrometer, whence were deduced hygrometric tables that 
were adopted by the Weather Bureau, and were undoubt¬ 
edly a great improvement on those of Regnault, which had 
been in use up to that time. 
(21.) 1886.—His “Meteorological Researches,” part III, on 
“ Barometric Hypsometry ” were made the basis of a report 
on the best method of reduction to sea-level practicable for 
stations that must telegraph the reduced observations 
promptly to a central bureau. These tables of July, 1886, 
must be recognized as responding, so far as any way practi¬ 
cable, to the demands of our knowledge of the subject, and 
although criticised by some, still seem to me to admirably 
respond to the conditions of the problem— i. e. } the reduction 
of mountain stations, high plateau stations, and low stations 
all to sea-level by one uniform method; but this is not to 
acknowledge that such a reduction to sea-level is a step 
proper to be taken as compared with the reduction upward 
to a uniform high altitude. 
(22.) 1889.—One of Ferrel’s last contributions to science 
consisted in the discussion of all the observations and 
theories of the radiation of heat from solids—a subject that 
must be recognized as of prime importance in meteorology. 
The fragmentary experimental knowledge that we have on 
this subject was thoroughly sifted by him and the path for 
future experimenters marked out. 
The sum total of the publications of our college aggregate 
about 3,000 octavo pages of formulae and tables, representing 
