[ 2 55 ] 
the fame time, I have pointed out, in what his 
principal miftakeconfifts ; which war, as M. de luc 
well observes, that, inftead of feeking a rule which 
fhould be general for ail heights, and vary at every 
height, in proportion to the temperature, he fet him- 
felf to find one which fhould be general for all tem- 
peratures, at a particular elevation. The confequence 
likewife, which he would have deduced from the 
unequal elaflicity of the particles of the air, that 
the lead elaftic would be driven to the bottom, was 
undoubtedly erroneous. The excefs of temperature 
may fail fometimes in the lower parts of the at- 
mofphere, and fometimes at greater heights ; and 
where the greater temperature is, there, creteris 
paribus, the elaflicity will be greater. The argu- 
ment, which M, de luc directs again ft the exiftence 
of fenfible inequalities of elaftic force in aggregate 
mafles of the atmofphere, derived from the fup- 
poled effect of the winds, throughout all the re- 
gions expofed to their agitations militates only 
againft the probability of permanent inequalities in 
given places, arifing from fuppofed fpecific differences^ 
in the original conftitution of the particles of the 
air; not againft fuch temporary inequalities, as we 
afcribe to the occafional energy of extraneous caufes^ 
An inequality of temperature undoubtedly exifts, 
in aggregate mafles, more frequently than the op- 
polite. And from an inequality of temperature,, 
whether in the aggregate or the difcrete, necefla- 
rily follows, for the time, an analogous inequality 
of abfolute elaftic force. 
(/) Rechercb. fur ks Modif. de l’Atm. §- 328. 
Having- 
