20 
The small cylinder A had an internal capacity of 573 cubic 
inches, while the large cylinder B had a capacity of 8459 
cubic inches, or about fifteen times the capacity of the 
for condensing the air up to nine atmospheres, and also a 
Bourdon’s pressure gauge of an improved construction, 
graduated through every lb. of the above pressure. The 
accuracy of this gauge was tested in my presence by the 
constructors, Messrs. Budenburgh & Co., through the whole 
range of pressure, by comparing its readings with a column 
