396 PHILOSOPHICAL TRANSACTIONS. [aNNO I767. 



shows that a great deal of fixed air is contained in Spa water. This induced 

 Mr. C. to try whether he could find any in that of Rathbone-place ; which he 

 did by means of the contrivance represented in fig, I, pi. 10. 



Here acdk represents a tin pan, filled with Rathbone-place water as high 

 as BG. HKL is another tin pan, within the first, in the manner of an in- 

 verted funnel, and made in such a manner, as to leave as little room as 

 possible between that and the sides of the outer vessel, m represents a 

 bottle, full of the same water, inverted over the mouth of the funnel. By 

 this means, as fast as the air is disengaged by heat from the water within the 

 funnel, it must necessarily rise up into the bottle. The Rathbone-place water 

 put into the vessel, weighed 411 oz., the funnel held 353 oz. A bottle full of 

 water being inverted over the mouth of the funnel, as in the figure, the water 

 was heated, and kept boiling about ^ of an hour. As soon as one bottle was 

 filled with air, it was removed by putting a small ladle under its mouth, while 

 under water, and set with its mouth immersed in the same manner in another 

 vessel of water, taking care not to suffer any communication between the in- 

 cluded air and the outward air during the removal. At the same time, another 

 bottle full of water was inverted over the mouth of the funnel, in the same man- 

 ner as the former. It was not easy telling how much air was discharged from 

 the water ; as the air in the bottles, when first removed, was hot and expanded; 

 and before he could be sure it was cold, there was some of it absorbed by the 

 water: but there seemed to be above 75 oz. measures discharged, scarcely 20 of 

 which arose before the water began to boil. The water continued discharging 

 air after the experiment was discontinued. In about a day's time, much the 

 greatest part of the air was absorbed, scarcely l6 oz. measures remaining. That 

 which was absorbed appeared to be fixed air, as the water which had absorbed 

 it, made a precipitate with lime-water. But in order to absorb all the fixed air 

 more perfectly, the air which remained not absorbed was transferred into another 

 bottle of water, in the manner described in Mr, C.'s first paper on factitious air, 

 p. 298, &c. of this volume. This bottle was then set with its mouth im- 

 mersed in a bottle of soap-leys; after which, ]:)y shaking the bottle, the soap-leys 

 was mixed with the included water; by which the air in the bottle was brought 

 in contact with the soap-leys, which is well known to absorb fixed air very 

 readily. By this means the air was reduced to 8^ oz. measures. A small phial 

 being filled with equal quantities of this and inflammable air, and a piece of 

 lighted paper applied to its mouth, it went off witii as loud a bounce, as when the 

 same phial was filled with equal quantities of common air and inflammable air. 

 The specific gravity of the remainder was tried by a bladder, in the manner 

 described in the above-mentioned paper: as well as could be judged from so 

 small a quantity, it was just the same as that of common air. From these 2 

 circumstances, Mr. C. thinks we may fairly conclude that this unabsorbed part 



