This will be seen, by the annexed sketch, to be identical in principle with the gazogenes, seltzogenes, and carbona-tors of the present day, and, indeed, with all machines which work by chemical pressure. The lowest vessel contains the materials for producing the "fixed air," or carbonic acid. The middle one the water to be carbonated. The upper one is for the reception of the water displaced by the carbonic acid gas through the bent tube. The process was to be accelerated by taking off the two upper vessels and shaking them. There is evidently a valve between the two lower vessels to allow the gas to pass upwards, but to keep the water from descending.

About the same time, Dr. Bewley (1767) also proposed to make artificial mineral waters, and it is probable that Dr. Priestley adopted some of his plans.

We have now reached the period when the study of chemistry suddenly emerged from a merely experimental stage into the position of an exact science, owing to the discoveries of the great French chemist, Lavoisier (born 1743, executed in French Revolution, 1794). Among his other investigations, he definitely traced the characteristics of the gas to which he gave the name of carbonic acid gas. He suggested a means of charging water with this gas, and his improvements include what we should term the "acid bottle," and a pump for producing the pressure (as suggested also by Priestley). In fact the last quarter of the 18th century may be looked to as the date of the invention of carbonated waters as an article of manufacture, and the honor seems to be divided among a good many claimants; but perhaps one of the chief shares belongs to Professor Torbern Olof Bergman, a Swedish chemist, (born 1735, died 1784), who appears to have "suffered in 1770 from a painful disease, which was much alleviated by the use of mineral waters obtained from Germany. The impossibility of getting these in the early spring led Bergman first to analyse, and then to compound them, which he did with remarkable success. His process consisted in generating carbonic (or as he called it "aerial") acid, impregnating water therewith, and then adding various mineral ingredients according to the particular spring he desired to imitate. He devised simple and efficient apparatus for generating carbonic acid from chalk and vitriolic acid, and the use of them became so popular even in the most distant Swedish Provinces, that women as well as men practised aeration with wonderful dexterity".He appears to have been indebted to the discoveries of the French Duke De Chaulnes (born 1741, died 1793), for the "agitator" which he used in the process of carbonating.

Fig. 53.   Dr. Nooth's Apparatus

Fig. 53. - Dr. Nooth's Apparatus.

Pierre Joseph Macquer, another French chemist, (born 1718, died 1784), also contributed to the completion of the apparatus by devising the means of washing and purifying the gas.

Since then to the present time the machinery for the manufacture of artificial waters has gradually been perfected.