504 PROCEEDINGS OF THE AMERICAN ACADEMY 



to the bottom of the bottle ; the third serves simply as a vent. The 

 bottles B and C are fitted each with two tubes, one to deliver the gas 

 at the bottom of the bottle, and the second, opening from the top, to 

 conduct away the excess. The gas generator A requires only an exit 

 tube, and lastly the wash bottle is fitted in the ordinary way, save only 

 that we pack it with well-washed sponge, by which the gas is more 

 effectually purified than when it bubbles through a liquid. We use 

 glass tubes of about j\ inch bore, and rubber hose of the same calibre, 

 but very stout, and made of pure vulcanized rubber. The rubber stop- 

 pers are cut from what we call stopper cord, which, as well as the hose, 

 is made by the Boston Belting Company, corner Chauncy and Bedford 

 Streets, Boston. In' mounting the apparatus, we interpose two or three 

 feet of hose between the several parts, so as to have sufficient free- 

 dom of motion to enable us to shake up the water with the gas in the 

 bottles B and C. Over the ends of the tubes from each of the bottles 

 B and C we stretch permanently two rubber connectors, cut from the 

 hose just described, and depend wholly on pressure taps, acting on 

 these connectors, for closing the bottles. While charging the water 

 with gas the connectors are united to the hose by short lengths of 

 glass tube, and subsequently the solution is drawn off through a bent 

 glass tube slipped into one of the same connectors. The bottles, thus 

 arranged, serve the same purpose as a soda-water siphon. The rubber 

 stoppers soon become cemented to the glass, and are never removed, 

 the bottles being filled, as they are vented, through the glass tubes. 

 A rubber connector with a pressure tap must also be provided for the 

 vent tube of the large bottle C, which serves, as we have said, to re- 

 ceive the unabsorbed gas. In charging the water, we leave the vent of 

 this gasometer open until the air is expelled from the apparatus, and 

 then connect the vent tube by a rubber hose with a manometer, which, 

 if a common steam manometer is not at hand, can be easily extempo- 

 rized with a glass tube and a little mercury. We now watch the pres- 

 sure, and when it becomes equal to the water pressure on our faucet, 

 we turn on the water head. On first opening the faucet, it is necessary 

 to watch the process very closely, lest the water should be forced back 

 into the generator, but the apparatus -soon adjusts itself to the new 

 conditions, and the absorption goes on as regularly as before. The un- 

 absorbed gas is of course stored in the bottle C, and gradually pushes 

 back the water, with which at first it is three fourths filled, into the 

 supply pipe ; but only a small portion of the gas is lost, and with the 



