2 FETAVEL, Compression of Gases by Hydraulic Apparatus. 



pump P, on the other with the gasometer through the 

 valve f. 



As compared with the ordinary compression plant,* 

 this apparatus has the advantage of simplicity, complete 

 safety, and relatively low cost. 



For the gasometer an inverted glass bell jar will be 

 found convenient. It is connected to the compression 

 cylinder and pump by rubber tubes. No motive power is 

 required, and almost any form of hand-worked hydraulic 

 pump can be used. The compression cylinder and 

 storage cylinders are of weldless mild steel \ or ^ inch 

 thick according to the working pressure required, and can 

 be obtained from the manufacturers who supply the 

 commercial gas cylinders. The high-pressure valves and 

 cone couplings are of the type previously described."}* 

 For connecting the various parts of the apparatus, flexible 

 copper tubing of about fin. external diameter and xV n - 

 bore is employed. 



With regard to the method of operating, a few words 

 will suffice. The gas coming slowly from the generating 

 apparatus passes through such purifiers as may be neces- 

 sary, and accumulates in the gasometer. From time to 

 time it is compressed into the storage cylinder in the 

 following way : — 



The valves b and /"are first opened, allowing the gas 

 to displace the glycerine contained in the compressing 

 cylinder, they are then closed again and the valve e 

 opened. The pump is now worked, forcing in the 

 glycerine and compressing the gas. When the gauge 

 indicates a pressure equal to that of the storage cylinder, 

 the valve g is opened and the gas allowed to enter. To 



* See R. S. Hutton and J. E. Petavel. Journ. Soc. Chem. hid., 

 1904, vol. 23, pp. 87—93. 



t J. E. Petavel, Phil. Trans., vol. 205, pp. 357—398. 



