This arrangement is for indicating the passage of the gas, and also washing it. The "outlet" of the indicator is attached to the gas cock of the pump; the pipe from the gas holder is connected with the "inlet". The gas passes down the vertical tube and up through the water, so that the attendant can see it pass at every stroke of the pump. It is also desirable to place an "indicator" between the generator and gas holder, so that the attendant can observe the flow of gas from the generator, and regulate its acid supply accordingly.

Leighton's "supersaturator," manufactured by Hayward Tyler & Co., London, Eng., is a new introduction in the trade. The illustrations on the next page show the system. The description is given as follows:

"It is well known to chemists that water will absorb a considerable quantity of carbonic acid gas (equal to its own bulk) without the addition of pressure. This principle is utilized in the 'supersaturator' in such a manner that the process of aeration is partly effected before the water enters the pump, to the great advantage of the product.

"The 'supersaturator' is placed between the gas holder and the pumps, (occupying the position of the ordinary solution pan), and the gas and water pass through it before entering the pump. The water enters through the pipe A and escapes in a shower through the rose B, being further divided in its descent by the gauze tray C. The bottom of the vessel remains full of water to a height regulated by the floating ball. The gas is admitted through the pipe G and escapes through small holes into the water, which partially dissolves it, the remainder rising through the vessel and meeting the falling shower from B and C. In this way the gas and water are brought into close contact, and the water absorbs about its own bulk of gas before leaving the vessel. The water passes to the pump of the machine through the outlet D and the gas in like manner through F.

Fig. 86   Supersaturator in Cooling Tank

Fig. 86 - Supersaturator in Cooling Tank.

Fig. 87.    Slate Supersaturator

Fig. 87. - -Slate Supersaturator.

"In hot weather it is recommended that the 'supersaturator' should stand in an outer vessel containing iced water H, the gas and water then pass into the machine thoroughly cooled, the water being capable of much higher aeration at a low temperature than at a high one".

The above engravings show the supersaturator as made in tinned copper and in slate. We prefer the latter plan on the ground of purity.

The patent corking and bottling machine seen attached in the next illustration, (Fig. 88), is described in the Chapter on Bottling.

Fig. 88.   General Arrangement of Carbonating Machinery

Fig. 88. - General Arrangement of Carbonating Machinery.

The separate horizontal generator as shown is described in the following manner: "It is made of heavy sheet lead, and lies in a horizontal position, on two cast-iron standards. The agitator or rouser, for stirring up the whiting, consists of a copper rod, passing through the whole length, working in a stuffing-box at each. end. The fans inside are of gun-metal, tinned, placed in an angular position, and secured to the rod by copper screws, and can be taken out when required at the large cap and screw on the top, and, with the rod, can all be removed and replaced without taking the generator to pieces. The agitator rod is not in the centre, but nearer the bottom; the fans are always immersed in the whiting, which they immediately stir up on being turned round either by the handle or steam power. It will be at once seen that in the case of large generators the whiting, when it settles to the bottom, will be more effectually broken up, distributed, and thrown to the top, to come into contact with the acid, in generators arranged in this way, than in the vertical generators with flat bottoms. The horizontal position is also better suited to drive the agitator by steam power by fixing a pulley on one end of the agitator rod. The generator is shown with a lead acid-box and inverted syphon pipe in preference to the acid bottle. This mode of feeding entirely prevents the possibility of exploding the generator; for if at any time too much pressure should be generated, from carelessness in putting in too much acid, the excess of pressure would simply blow the acid back again into the box, which is covered over to prevent it being thrown out. The acid box is generally fixed to the wall near the generator, just high enough to reach and pour in the acid at a small funnel shown. The acid bottle, if preferred, can easily be attached. The spent whiting is let out at the bottom by a slide valve; and the gas makes its exit to the gasometer by a pipe attached to the union joint on the right-hand end of the generator.

"The gas holder consists of a bell of strong sheet copper, tinned inside, suspended by the centre, and rising and falling freely in a cylindrical vessel of water made of strong oak, that material being both very strong and durable, and very pure. In the interior of the gas holder are two pipes, one of which (for the admission of the gas) after rising above the surface of the water turns down again, so that the gas should be passed through the water and purified. We recommend that this pipe should terminate in a rose with very small holes, or other similar means by which the gas should escape in very small bubbles, and so become thoroughly exposed to the washing action of the water. The other pipe terminates above the surface of the water, and carries away the gas to the machine. These pipes are usually made of copper tinned; but we prefer to use solid tin for greater purity. The water in the gas-holder tank should be frequently emptied to keep it quite clean".