pues 
ere 
Prof. J. Lovering on the Aneroid Barometer. 251 
made of the subject in the Report of the.Association for that 
year. As the reader is not informed to what amount of dimin- 
ished pressure the aneroid barometer was subjected in this case, 
and whether the difference above mentioned was the result of a 
single observation or the mean residuum of many, he is not able 
to decide how far the experiments to which Mr. Lloyd refers are 
at variance with those here published. I cannot say how much 
of the error manifested in my comparison of the two barometers 
is fairly to be charged to the general character of the new barom- 
eter, and how much is peculiar to the single instrument with 
which [ experimented. As soon as an opportunity offers, I desire 
to submit other specimens of the aneroid barometer of English 
and French construction to the same trial. 
My next series of experiments consisted in a comparison of 
the aneroid barometer, day by day, with the common barometer, 
Jones, London, and is the same as that employed by Prof. Farrar 
in his barometric observations published in Volume IIL. of the Me- 
moirs of the American Academy, Boston. This instrument is 
furnished with an adjustment for level, an attached thermometer 
and a scale of corrections for temperature. This correction as 
cate the exact temperature of the working parts of the instrument. 
The slowness with which the index returned to its old mark, after 
