Hydro-pneiimatic Apparatus. 251 



Fig. 8 is a ground plan of the cap n of fig. 7. Oiie of the 

 advantages of this construction isj that in filling a large receiver 

 with water from the trough, the deficiency of the fluid can be 

 supplied by raising it from the lower vessel by the breath, and it 

 is retained in the upper compartment of the trough by the slid- 

 ing tube n (fig. 7) being drawn up above the surface of the fluid. 



When the water in the receiver is displaced by the gas, the 

 redundancy is let off into the lower vessel by the same tube. 



By this contrivance, the necessity of pouring in or emptying 

 out water through the help of another vessel is obviated, and the 

 operator relieved from that inconvenience. 



The broad surface of the upper part of the pneumatic trough 

 is particularly adapted to keep tlie pressure of water equal on the 

 air, which produces a uniform flame, the altitude of the water 

 being little affected, as well as presenting the most convenient 

 form for pneumatic purposes. 



Fig. 4 is the cover of the apparatus inverted, which becomes 

 a tray to which the receivers may be transferred when filled with 



^■^'•^ 



The two tubes o aiid p are to prevent the water which is in 

 the tray (to keep the receivers air-tight) from passing through 

 the holes. 



Fig. 9 is a ground plan of the lamp on a moveable shelf. 



Fig. 10 is a side view of the moveable shelf and lamp. 



Plate V. fig. 1, is a perspective front view of the apparatus, 

 to show the moveable shelf, and the manner of attaching it to the 

 tubes e and f by the bayonet catch, as it may be necessary to 

 employ the lamp when the cover is in use as a tray. 



Fig. 2 is a perspective side view of the same. 



Fig. 6 is the bladder of gas, with a stop-cock and connecting 

 pipe. 



Fig. 5 is a gas-holder that fits into the well of the pneumatic 

 trough, with an attached stop-cock t. 



Fig. 3 is the same vessel inverted, the stop-cock being re- 

 moved, and the aperture made water-tight by the screw s (fig. 4) '^ 

 by the addition of a moveable shelf, it becomes a small pneumatic 

 trough. 



Fig. 4 is a section of the above, showing the trough furnished 

 with its shelf and a hemispherical chamber r, connected to its 

 under side, to ensure the gas from the retort to pass only through 

 the hole in the shelf, as also effectually to preveut the retort fron\ 

 slipping out of its position. 



R2 XLI. Fadi 



