SODA FOUNTAIN. This term was used to designate the equipment from which carbonated water, flavored and sweetened, is drawn and dispensed. An apparatus to serve soda water in a glass or tumbler instead of from a bottle came kvith the develop ment of carbonating machinery. English and French manufac turers in the period from 180o to 1825 devised improved equipment for making what was called "soda water." One im provement was a strongly built metal tank, cylindrical in form and holding several gallons of water, in which carbonic gas entered. This "cylinder," as it was called in England, and a "fountain" in the United States, was mounted on a frame and was rocked back and forth so as to increase the saturation of the water by the gas. The cylinder, being portable, was placed under the counter in the shop, and the soda water was drawn through a pipe which had a draft arm above the counter.
The important changes and improvements in the fountain have been made by American manufacturers. About 1855 the marble soda fountain was introduced, the apparatus being a marble box with an ice-chest to cool the coil of pipe and a metal container for the syrups which were drawn from a row of faucets. The early soda fountain changed from time to time as improvements were made. At first carbon dioxide was obtained by the interaction of an acid and a carbonate, then the gas was prepared from various sources—from natural gas, collected from brewers' fermenting vats, and from burning coke. The last-named source now supplies most of the carbonic gas, which comes in liquid form in steel tubes for carbonating beverages. Other improvements made in recent years are mainly in perfecting the carbonating machinery, in mechanical or electric refrigeration, in extending the service of the soda fountain, and in simplifying the working of the equip ment so that the process or system is more or less automatic.
The present-day standardized soda fountain is built on a steel or iron frame. It resembles a long, narrow metal box, thoroughly insulated and sealed to keep out air and heat, and is divided into many sections and compartments. A io ft. fountain unit is commonly equipped with a cooling chamber for soda and ice water, two or three compartments for chipped ice, four cabinets for holding 5 gal. of bulk ice cream in cans and two cabinets for 5 gal. of brick ice cream, six syrup jars with pumps, four crushed fruit jars, one or two dry cold storage compartments for fresh fruits, milk or bottled goods, and two open sections (one at each end of the counter) with drainboard, sink, tumbler rinsers, a dish and spoon vat.
Soda fountains are made in two styles, the counter fountain and the back bar fountain. The latter has a so-called bar back
of the counter, a structure 3 or 4 ft. high with a polished wood, tile or marble cornice supported on the two sides by columns of similar materials to match, with shelves for a display of glass ware or candy, and with a large mirror in the centre.
At the present time the soda fountain is to be found every where in America : in most drug and candy stores, in department stores, in motion picture houses and at the road-side stands and inns for the patronage of tourists and the travelling public. The "soda parlor," as it was originally called, has developed into the soda fountain luncheonette—a place where not only an infinite variety of drinks, but foods such as soup, bouillon, sandwiches, salads, pastry and cake, are served. It is estimated there are from 90,00o to Ioo,000 fountains in the United States. The number of fountains in the European countries is rather small, probably not more than i,000, and the demand has increased slowly. The soda fountain is becoming popular in Canada and in South American countries, and in the Australian Commonwealth where some 2,500 are now in use. (L. J. V.) SODALITE, a member of the group of rock-forming min erals comprising the following isomorphous species :— Sodalite . . . . Na4(A1C1) Al2( SiO4)3 Haiiynite (Na2Ca)2(NaSO4.AD Al2(5iO4)3 Noselite Na4 ( NaSO4.A1) All ( SiO4)3 Lazurite Na4(NaS3•Al) Al2( SiO4)3 These are sodium (or calcium) aluminium silicates, with chloride, sulphate, or sulphide. In their orthosilicate formulae, as above written, and in their cubic crystalline form they present a certain resemblance to the members of the garnet group. Crystals usually have the form of the rhombic dodecahedron, and are often twinned with interpenetration on an octahedral plane. They are white, or often blue in colour, and have a vitreous lustre. The hardness is 51, the specific gravity 2.2-2.4. These minerals are character istic constituents of igneous rocks rich in soda, and they also occur in metamorphic limestones.
The species sodalite (so named because it contains soda) occurs as well-formed, colourless crystals in the ejected limestone blocks of Monte Somma, Vesuvius. In the elaeolite-syenite of Dun gannon in Ontario bright sky-blue material has been quarried for use as an ornamental stone. Haiiynite, or hailyne (named after R. J. flatly), occurs as bright blue crystals and grains in the lavas of Vesuvius, Rome, the Eifel, etc. Noselite, or nosean, is found as greyish crystals in the sanidine bombs of the Eifel. Lazurite is an important constituent, together with some hailynite and sodalite, of lapis-lazuli (q.v.). (L. J. S.) SODA WATER : see AERATED WATERS.