Hydro-Oxygen Blowpipe Jbr the Fusion of Platinum, 361 



with gas, the cock E must be shut. Whenever the gas is 

 wanted for the supply of the blowpipe, it is only necessary to 

 establish a communication between the valve-cock B and the 

 upper gallows-screw (fig. 3) of the cylinder A, and to open the 

 cock F, so as to admit the water to press upon the gas, the 

 efflux being regulated by B, or preferable by a cock of the 

 ordinary construction, one of which kind should be interposed 

 at a convenient position between the valve-cock B and cylin- 

 der A. 



T represents a glass tube, which, by due communication 

 with the interior, shows the height of the water, and conse- 

 quently the quantity of gas in the vessel. 



G H represents a gauging apparatus, consisting of a cast- 

 iron flask, of about a half pint in content, and a glass tube of 

 about a quarter of an inch in bore, which should be at least 

 five feet in height. The tube is secured air-tight into the neck 

 of the flask, so as to reach nearly to the bottom within. The 

 flask is nearly full of mer- 

 cury. Under these circum- 

 stances, when a communi- 

 cation is made by a leaden 

 pipe between the cavity of 

 the flask and that of the 

 reservoir, an equilibrium 

 of pressure resulting, the 

 extent of the pressure is 

 indicated by the rise of the 

 mercury in the tube. 



In order to generate hy- 

 drogen for the supply of a 

 reservoir like that repre- 

 sented by the preceding 

 figure, I have employed the 

 vessel represented by fig. 7. 

 This vessel, by means of a 

 suitable aperture, suscep- 

 tible of being closed by a 

 screw-plug, is half-filled 

 with diluted sulphuric acid. 

 Being furnished with a tray 

 of sheet copper D, punc- 

 tured like a coal-sieve, and 

 supported by a copper sli- 

 ding- rod E, strips of zinc 

 are introduced in quantity equal to the capacity of the tray. 

 The sliding-rod passes through a stufling-box F, at the top of 

 the reservoir, so that the operator may, by lowering or raising 



E 



