WATER. 207 



Large self-regulating reservoir, for Hydrogen. 



" This figure represents a self- 

 regulating reservoir, for hydrogen 

 gas; it is constructed like that 

 described in the preceding arti- 

 cle, excepting that it is about 50 

 times larger, and is made of lead 

 instead of glass." 



" This reservoir is attached to 

 the compound blowpipe, in or- 

 der to furnish hydrogen ; and 

 may, of course, be used in all 

 experiments, requiring a copious 

 supply of that gas." 



On account of the extensive 

 uses of oxygen and hydrogen 

 gases, in a philosophical labora- 

 tory, it is highly convenient, to 

 have them always on hand, in 

 large quantities ; and, of course, 

 in separate reservoirs, between 

 which there is no possibility of 

 communication. 



WATER. SYNTHESIS. 



11. THE COMBUSTION OF HYDROGEN PRODUCES WATER, and pTC>- 



vided the gases be pure,* it produces nothing else. 



(a.) Burn a jet of hydrogen gas in a tall glass tube, and water, in 

 visible drops, will soon line the tube. 



(b.) The same may be done in a bottle, filled either with common 

 air, or with oxygen gas. . 



(c.) Or burn a double stream of the two gases, coming from 

 distinct reservoirs, and mingling at the moment of exit. 



In these cases the receiver should be kept cold. 



(d.) If a bladder, furnished with a stop cock, and a bent tube, be 

 filled with hydrogen gas, and the gas, kindled in a. jet, be allowed 



* Sometimes a little nitric acid or nitric oxide, is formed at the expense of the ni- 

 trogen; or carbonic acid, from carburetted hydrogen, these being accidental im- 

 purities in the gases. 



