238 
Liquefaction of Oxygen. 
[April, 
Description of the Drawings. 
a. A tube, 5 metres long, 14 millimetres external diameter, and 4 millimetres 
internal diameter, in which the oxygen condenses. It is furnished with 
a screw-tap, r, from which the liquid oxygen jets out. A pressure- 
gauge, M, measures the pressure up to 800 atmospheres. 
b. A tube, 4 metres long, in which is solid carbonic acid. The stock of car- 
bonic acid is contained in a gasometer, g, of 1 cubic metre capacity. 
A three-way tap, h, puts it when desired into communication with the 
apparatus. 
c. A howitzer shell, containing 700 grms. of chlorate of potash mixed with 
chloride of potassium. It is heated with gas. 
Pi, P2. Double-a&ion exhaustion and force pumps, drawing carbonic acid from 
the tube b or the gasometer g, according to the position of the tap h. 
s. A tube, 60 millimetres diameter and i*i metres long, in which is condensed 
the liquid carbonic acid compressed by the pumps. This liquefied gas 
returns by the small tube t to the tube b. 
