fSa Description of a Hydro-pneumatic Table, 



be used, the X.T^.y x x x^ together with its cistern a (7, and 

 stage or plain ^, is to be filled with water, so as to stand 

 at least three fourths of an inch deep over the shallow 

 plain or stage b in every direction. Across the cistcrii 

 fl a is a shelf, marked c in the drawing; it is five inchei? 

 broad, and perfectly level with the stage b. This shelf 

 slides backwards and forwards horizontally within the 

 cistern a, so that it may be placed at any convenient di- 

 stance from the lamp furnace, fig. 2, or other vessel 

 from which gas proctcd^. It is provided on its foremost 

 edge with a row of holes, into which from underneath, 

 broad short-necked funnels are fixed ; it serves to sup- 

 port the receivers standing on the shelf r, with their 

 open ends turned downwards upon the before-mentioned 

 holes, through which afterwards the gas conveyed by 

 the funnels is made to pass into the jars de3tined to receive 

 it. As this shelf is level with the stage, and may, by 

 its sliding motion, be brought close to the stage b where 

 it terminates in the cistern, the jars placed upon this shelf, 

 when filled with gas, may be slided along without further 

 trouble to a distant part on the adjoining plain b, whilst 

 other vessels previously filled with water in the cistern a a, 

 and standing also on the plain b, may in return instantly 

 be itioved on the shelf c ; and thus the trouble of removing 

 the jars into and out of the cistern is totally av^oided. 



From this statement it will be seen that the advantages 

 of the pneumatic table are considerable. It enables the 

 operator to fill jars or vessels with the utmost neatness, 

 convenience and expedition. The necessity of trans-, 

 ferring them when iilled with gas, olit of the trough; 

 is avoided, and the danger of suffering part of the gas 

 to escape, as well as the almost unavoidable spilling of 

 \V'ater whilst the vessels are removed, is completely guarded 

 against. It enables the operator also to fill jars of almost 

 any size, which cannot be done in the common trough,- 

 without rendering ft unwieldy and very cumbersome, oi* 

 without being at least obliged to immerse the jars pre- 

 viously into a deeper troligh, and thence conveying them 

 upon a plate or saucer into the reservoir in which the^ 

 are to be filled with gas. Thus the constant danger of 

 having either too much water, so as to overflow the trough, 

 or loo little, so as to admit common air to enter into 

 the jars when the water sinks belovv the ^helf, is effec- 

 tually remedied. In thl* common trough the vessels are also 

 exceedingly liable tO' be overset by the prcsi^ure of th^ 



waterji 



