ABBE. 
28 
Owing to the numerous relations between the study of the 
atmosphere and every other branch of science, meteorology 
has been from time to time classed as a part of chemistry, 
physics, geology, and geography, but is now assuming an 
independence that justifies its recognition as a distinct sub- 
ject; this fact requires us to explain distinctly of what 
meteorology consists. It is not a mere description of atmos- 
pheric phenomena, neither is it a system of maps and predic- 
tions; it is not a popular climatology, nor merely a mathe- 
matical study of the motions of the atmosphere. We must 
define it as embracing the broadest conceivable study of the 
atmosphere from any and every point of view; if we sub- 
divide it according to the difficulty of the subject and the ex- 
tent of our ignorance, beginning with the simplest and pass- 
ing on to the more difficult portions, we may subdivide it 
into descriptive climatology, optical and acoustic phenom- 
ena, thermal or thermodynamic phenomena, hydrodynamic 
or mechanical phenomena. The two latter classes of phe- 
nomena constitute the subject-matter of the mechanics of the 
atmosphere and include all that relates to temperature, pres- 
sure, winds, cloud, fog, dew, rain, snow, hail, and the daily 
prediction of storms and weather. It is in the study of these 
phenomena that the progress of our science has been most 
conspicuous during the past century; the problems already 
partially solved involve so much of the most profound mod- 
ern physics and mathematics that one cannot refuse to me- 
teorology a notable place among the most difficult branches 
of science. Fundamentally, meteorology is the mechanics 
of the earth’s atmosphere; all its other aspects are of minor 
importance to this and it is our progress in this line of 
research that should especially claim our attention. 
A general historical survey of the methods by which we 
have arrived at the present state of our knowledge of nature 
will show that meteorology has passed through the various 
stages of development that have been common to all the 
sciences, and that in its present stage of vigorous growth it 
already stands among those that have progressed the farthest. 
The methods of advancing our knowledge of nature have 
