ON ARGON AND ITS COMPANIONS. 
51 
air is compressed by a “torpedo air-compressor” made by the Whitehead Company 
of Fiiime, Austria; it enters the com 2 )i*essor through a low-pressure A, 
consisting of a drum fitted with trays, eacli covered with slaked lime, to effect a 
preliminary ahsorjDtion of carbon dioxide. In the first cylinder, B, it is comiiressed 
with a pressure of about 60 atmosj^heres, and passes through a tul)e C to the 
intake valve of tlie second cylinder D, where the i^ressure is raised as high as is 
desirable ; the air then passes through the cooling coil E to the separator F, where 
the water which enters the cylinders for the i^urjwse of lubrication, is sejiarated and 
discharged at the cock G ; it joasses through a high-jjressure purifier H, chai'ged 
with caustic j^otash in lumps, which removes water-vajjour, and any carbon dioxide 
which may have escaped ahsor 2 )tion in the low-|)ressure juirifier. From the high- 
2 )ressure purifier, it enters the licpiefier. The jiower required to drive the coinj^ressor 
is about five horse-^^ower ; and when working at a jjressure of 175 atmosjjheres, it 
delivers a litre-and-a-quarter of liquid air jier hour. The air begins to run liquid in 
eight minutes after starting the compressor ; and the amount of attention it requires 
is no more than that of an ordinary steam-engine, in oiling, cleaning, &c. 
The a 2 ) 2 )aratus employed in fractionating the gases was similar to that described 
in the ‘ Proceedings,’ vol. 64, 188. To that description there is notiiing to add, 
save that the bullj h in the figure is relatively much smaller, when only smafi 
amounts of gas are availaljle ; and the tube-reservoir a, had a capacity of 35 cub. 
centims. It was also jjossible to compress the gas in a by raising the attached reservoir. 
H 2 
