VNEUMATIC COMPRESSION SQUIRTERS. 255 



corked bottle, or other vessel, contaiued iu a larger tight jar or vessel 

 with the bicarbonate between the two, so that by tipping the whole more 

 or less of the acid is turned into the carbonate. 



Plate XXXY, Fig. 3, shows a plan for generators of this kind, in 

 which the acid bottle, a, in the interior is surrounded by the bicarbonate, 

 b, in an ordinary two-quart fruit jar with a lead screw-cap perforated 

 by the outlet spout, c, for exit of the gas which is conducted through 

 the hose, 7i, iuto the top of the barrel or reservoir contaiuiug the poison. 

 By having the two chambers thus compactly conjoined the apparatus 

 is simple and handj" as a small generator. 



But there are certain advantages in having the two chambers separate 

 and connected by means of a flexible tube, and this construction is surely 

 one often to be preferred for large generators, when a cheap home-made 

 apparatus is wished. The short piece of flexible tubing should be of 

 good rubber, and although the acid corrodes it somewhat, it will endure 

 for one season at least, when a new i^iece can be substituted at a trifling 

 cost. Fig. 4 in plate XXXV shows this apparatus. The jar, /, contains 

 the bicarbonate, h. Its screw-cap, t, is made of lead. From this is a 

 lead outlet tube, e, couj^led to the reservoir, r, of poison, p. The cap is 

 also perforated by the lead tube,j, coupled to the hose, h, leading from 

 the acid-bottle, a. The latter is to be elevated and inclined by one hand 

 to pour the acid into the bicarbonate. Thus at intervals a few minutes 

 apart a little acid is added. When the driver sees that the spray is not 

 going as high as desired he applies a little splash more of the acid to 

 increase the pressure. This is one of the easiest ways in the world for 

 spraying poison. It is really more pleasure than labor. In the gen- 

 erator, t h, considerable heat is evolved and it will often become too hot 

 to be handled. On this account it. had better be so fixed that it need 

 not be touched and its temperature may be kept down by keeping it 

 wet. It is easily hauled or carried in a bucket containing some water 

 with a little soft packing material beneath and around it. .The less the 

 amount of water mixed with the bicarbonate, the less heat will be gen- 

 erated, but enough water should be employed to wet the soda, other- 

 wise the sodic sulphate formed by the chemical process arises as a crust 

 and keeps the acid from reaching the remainder of the bicarbonate, 

 thus retarding or stopping the generation of gas. 



These pressure generators are cheaj), of simple construction, easily 

 understood and used by any one, while the action is under perfect con- 

 trol, and danger from bursting does not exist. There is no need of 

 l>ntting in too much acid and running the pressure too high. 



The rubber gum hose is stout enough to squirt the poison as high as 

 needed, but the gum will give way and burst before a pressure if any 

 danger is attained. Thus there is nothing to fear from explosions. 



The acid is a very injurious poison and should be handled with great 

 discretion; but the bicarbonate used with it is always at hand as a sure 

 antidote, and on the ground of its being dangerous the acid is.no more 



