t^% Mr. Austin on a new Construction 



Figs. 1 and 2. 



[a) The upper vessel which contains the liquid to be im- 

 pregnated with the gas. A safety valve closes its mouth, seen 

 atlarge, fig. 5(P1.XIV.) 



(6) A piece connected permanently to the upper vessel ; it 

 carries the valve, which is so far below its surface as to allow 

 it to rise a little in action, but not to turn over: the plane 

 side of the lens is indented with a deep cross cut, to allow 

 the gas to pass over it into the upper vessel, seen at large, 

 fig.6,g. ^ (PI. XIV.) 



(c) The glass barrel having a broad ring on each end. 



Length of the barrel - 13. inches. 



Diameter of the bore - - o. J 



External diameter - i.-J 



Diameter of the broad rings - s.J- 



[d) The hollow glass piston having one broad ring next 

 (f ), for the flat joint which connects the piston with it, and 

 another ring, about four inches above this last, in order to 

 secure it the better to tlie frame in wliich this ring and the 

 piston are more than half surk, and then covered over by a 

 piece of mahogany pressing upon it with four screws. The 

 covered part of the piston is represented by the dotted lines 

 near {d) in fig. 1. At the end of the piston are two small 

 rings, to confine the packing by which it is fitted to the barrel; 

 and the extremity is ground into the hollow segment of a 

 sphere, into which is fitted an unpolished plane convex lens, 

 fig. 2, and seen at large, fig. 6, 



(^) The receiver, from which the gas is drawn up and 

 condensed into the upper vessel [a). It is furnished with a 

 ground stopper, which may be used occasionally as hereafter 

 mentioned. 



