AMERICAN INSTITUTE. 119 



tlie rod at 8; tJien pxjur into the chamber at 9, two pints of oil of vitriol, and after 

 greasing the screw with a piece of tallow, screw the brass cap on tightly. 



To make the gas, raise the valve in the vitriol chamber at 8, and watch thepres- 

 sare gauge; as soon as it indicates 10 lbs. on the inch, close the valve, and turn the 

 agitator on the generator, slowly, at 11; this will increase the pressure considera- 

 bly, but if it does not rise to 100 lbs. on the inch in a few minutes, more vitriol 

 must be let down by raising as before the valve rod at S, and the agitator of the 

 generator turned slowly as before. As soon as the pressure reaches 100 lbs., open 

 the cock on the fountain by screwing the handle to the left as many times as may- 

 be necessary to bring it tight, for it is never tight unless screwed back as far as it 

 will go, with the hand^ the cock 7 «n the washer may then be opened, to allow 

 the gas to run into the fountain; this will diminish the pressure on the generator 

 a^id washer, but it must be agiiin raised to 100 lbs.; the pipe on the fountain must 

 then be taken oW, first closing the cock on the washer by screwing the wheel to 

 the right, and then the cock on the fountain by turning the handle to the right 

 with the hand, until it will turn no further; tlien take the pipe off the fountain, 

 and agitate the water by swinging the fountain round, and by holding it in a hori- 

 zontal position and shaking it for a few minutes. The fountains sliould then be 

 again connected, and the cocks opened (care being taken to open first the cock oa 

 the fountain); the gas should pass very slowly into the fountain, and the pressure 

 should stand at 100 lbs, for a few minutes. The pipe may then be taken off and 

 the water in the fountain imitated as before; after which it may again be connected, 

 and the cocks opened- If tlie pressure is not 100 pounds, it must be raised to tliat 

 point by turning the handle of the generator slowly, and opening the valve on the 

 vitriol chamber. 



If the generator should leak at 11, or the vitriol chamber at 8, the nut on the 

 rod should be screwed up until it ceases t© leak. When, however, the leak cannot 

 be stopped, or the nut is screwed up as fiw as it will go, the stuffing box requires 

 repacking, (for dcing which see directions.) 



The charging pipe should now betaken off the fountain, and the pipe 17, from 

 the draught tube attached, and after opening the cocks on the fountain and washer 

 the soda water is ready for use. The remaining gas must be permitted to escape 

 very slowly, by opening the cock 7 on the washer, a little. When it has all es- 

 caped, it may be known by the pressure gau^3 returning to Bero. If the gas is 

 drawn off too rapidly, the materials in the generator are liable to boil over and 

 obstruct the pipes and washer. 



The caps on the generator may now be unscreMTe'd and the refuse materials 

 emptied. The generator must be washed out well with clean water, and the cap 

 3 under it screwed on again, takieg care to wash every screw free from marble 

 dwst. 



The charge of water and marble may be then poured into the generator, ready 

 fer the next time. 



The water in the washer must he renewed every time, by unscrewing the plug 

 at 2, and after the water has run off", and the washer well rinsed with clean water, 

 replace the plug 2 and charge with fresh water, and then screw on the plug 4- 



The vitriol should not be poured into the chamber until the charge is wanted, 

 nor should it be permitted to remain longer than necessary, and care should pe 

 taken before pouring in the vitriol, to close the valve in the vitriol chamber, which 

 may be doae by pushing down the rod on the vitriol chamber at 8. 



Spda water is simply pure water impregnated with carbonic acid gas. Some- 

 times a minute portion of carbonate of soda, or Rochellc salts, is added to the 

 water previous to charging it with the gas. 



