little water, I condensed it in the manner already described, and when condensed I allowed half the fluid to escape in vapour, that as much as possible of the less con dens able portion might be carried off. In this way as much gas as would fill the capacity of the vessels twenty or thirty times or more was allowed to escape. Afterwards the following series of pressures was obtained:—
| Fahr. | Atmospheres. |
| -125 | 1.00 |
| -120 | 1.10 |
| -115 | 1.22 |
| -110 | 1.37 |
| -105 | 1.55 |
| -100 | 1.77 |
| -95 | 2.03 |
| -90 | 2.34 |
| -85 | 2.70 |
| -80 | 3.11 |
| -75 | 3.58 |
| -70 | 4.11 |
| -65 | 4.70 |
| -60 | 5.36 |
| -55 | 6.09 |
| -50 | 6.89 |
| -45 | 7.76 |
| -40 | 8.71 |
| -35 | 9.74 |
| -30 | 10.85 |
| -25 | 12.04 |
| -20 | 13.32 |
| -15 | 14.69 |
| -10 | 16.15 |
| -5 | 17.70 |
| 0 | 19.34 |
| 5 | 21.07 |
| 10 | 22.89 |
| 15 | 24.80 |
| 20 | 26.80 |
| 25 | 28.90 |
| 30 | 31.10 |
| 35 | 33.40 |
These numbers may all be taken as the results of experiments. Where the temperatures are not those actually observed, they are in almost all cases within a degree of it, and proportionate to the effects really observed. The departure of the real observations from the numbers given is very small. This Table I consider as far more worthy of confidence than the former, and yet it is manifest that the curve is not consistent with the idea of a pure single substance, for the pressures at the lowest temperature are too high. I believe that there are till two bodies present, and that the more volatile, as before said, is con dens able in the liquid of the less volatile; but I think there is a far smaller proportion of the more volatile (nitrogen, or whatever it may be) than in the former case.
Olefiant Gas.—The olefiant gas condensed in the former experiment was prepared in the ordinary way, using excellent alcohol and sulphuric acid; then washed by agitation with about half its bulk of water, and finally left for three days over a thick mixture of lime and water with occasional agitation. In this way all the sulphurous and carbonic acids were removed, and I believe all the ether, except such minute portions as
