458 
WILLIAM FERREL. 
The views elaborated in these two parts, as we all know, 
have marked an epoch in the history of meteorology, and 
have stimulated numerous other students of this science. 
Here, as elsewhere, Ferrehs work is marked by a rigid logic 
and a remarkable discrimination in selecting for considera¬ 
tion the important factors in the production of natural phe¬ 
nomena. These memoirs were further elaborated in 1885, 
in his “ Recent Advances,” and were presented in an un- 
mathematical and so-called popular form in 1889 in his 
“ Popular Treatise on the Winds.” Ferrel held to the view 
that the progressive motion of a storm of any extent is con¬ 
trolled by the general circulation of the atmosphere, or, 
perhaps, I may with equal propriety say the storm is a part 
of and temporarily represents the general circulation as 
modified by local conditions. At the same time he was di¬ 
rectly and consistently opposed to those who would attribute 
the fall of the barometer to the mechanical effect of the 
general circulation alone, since he gave us the correct formula 
by which to calculate the combined effect of general and 
local circulation. 
Ferret’s elaborate article on waterspouts, tornadoes, and 
hail-storms has been widely quoted as particularly happy 
and convincing. 
(18.) 1882.—In his memoirs on the “ Conditions determin¬ 
ing Temperature” in the atmosphere and at the earth’s service, 
Ferrel achieved several advances, namely: First, the observed 
distribution of temperature in the northern and southern 
hemispheres was charted and formulated as preparatory 
to the theoretical computation of the pressure and resulting 
general circulation of the winds; second, the theoretical 
relation between the temperature shown by a thermometer 
and that of surrounding objects was formulated, whence 
he deduced the proper and best method of determining the 
true temperature of the air; third, the relation between the 
temperatures of the black bulb and bright bulb thermom¬ 
eters was investigated, whence he deduced the proper method 
of determining the amount of heat received from the sun 
