L £24 |] 
by the addition of fomething, or 
by becoming deprived of fomething 
extraneous to its Own original fim- 
ple mature;~we can no more be 
furprized to find, that the conftitu- 
tion of the atmofphere remains fel- 
dom a whole day the fame, and that 
| ee of falubrity is continually 
cing. ‘Indeed, in the courfe of 
e months, which I fpent in my 
Solicdey retirement, I fcarce found 
the degree of falubrity of the com- 
mon air juft the fame during two 
days. i 
_ Thofe who are not yet acquainted 
with the accuratenefs of Abbé Fon- 
-\tana’s new Eudiometer, will be much 
inclined to believe, that the appear 
ance of fuch continual variations 
is More owing to the imperfection 
of the method of exploring the aif, 
than to the real changes happening 
' : in 
= 
