from this air by milk of lime, then a candle can burn in it again, although only for a very short time. +23. Seventh Experiment.+--I placed upon the stand (§ 21. _b._) a small crucible which was filled with sulphur; I set fire to it and placed the flask over it. After the sulphur was extinguished and everything had become cold, I found that out of 160 parts of air, 2 parts were driven out of the flask by the heat of the flame. I next poured 6 ounces of clear lime water into the flask and dealt with it by shaking, as already explained, and observed that the sixth part of all the air had been lost in consequence of the combustion. The lime water was not in the least precipitated in this case, an indication that sulphur gives out no aerial acid during its combustion, but another substance somewhat resembling air; this is the volatile acid of sulphur, which occupies again the empty space produced by the union of the inflammable substance with air. It is not, as may be seen, a trifling circumstance that phlogiston, whether it separates itself from substances and enters into union with air, with or without a fiery motion, still in every case diminishes the air so considerably in its external bulk. +24. Experiments which prove that ordinary air, consisting of two kinds of elastic fluids, can be compounded again after these have been separated from each other by means of phlogiston.+ I have already stated in § 16 that I was not able to find again the lost air. One might indeed object, that the lost air still remains in the residual air which can no more unite with phlogiston; for, since I have found that it is lighter than ordinary air, it might be believed that the phlogiston united with this air makes it lighter, as appears to be known already from other experiments. But since phlogiston is a substance, which always presupposes some weight, I much doubt whether such hypothesis has any foundation....