vapour over it at the temperature of 86° Fahr., and the former is little more than twice that of the latter; hence a few degrees more of temperature would bring them together, and Brunel's result seems to imply that the state was then- on, but in that case Addams's results could only be accounted for by supposing that there was a deficiency of carbonic acid. The following are the pressures which I have recently obtained:—
| Fahr. | Atmospheres. | |
| * | -111° | 1.14 |
| -110 | 1.17 | |
| * | -107 | 1.36 |
| -100 | 1.85 | |
| * | -95 | 2.26 |
| -90 | 2.77 | |
| * | -83 | 3.60 |
| -80 | 3.93 | |
| * | -75 | 4.60 |
| -70 | 5.33 | |
| -60 | 6.97 | |
| * | -56 | 7.70 |
| -40 | 11.07 | |
| * | -34 | 12.50 |
| -30 | 13.54 | |
| * | -23 | 15.45 |
| -20 | 16.30 | |
| * | -15 | 17.80 |
| -10 | 19.38 | |
| * | -4 | 21.48 |
| 0 | 22.84 | |
| * | 5 | 24.75 |
| * | 10 | 26.82 |
| * | 15 | 29.09 |
| 20 | 30.65 | |
| * | 23 | 33.15 |
| 30 | 37.19 | |
| * | 32 | 38.50 |
Carbonic acid is remarkable amongst bodies for the high tension of the vapour which it gives off whilst in the solid or glacial state. There is no other substance which at all comes near it in this respect, and it causes an inversion of what in all other cases is the natural order of events. Thus, if; as is the case with water, ether, mercury or any other Huid, that temperature at which carbonic acid gives oif vapour equal in elastic force to one atmosphere, be called its boiling-point; or, if (to produce the actual effect of ebullition) the earbonic acid be plunged below the surface of alcohol or ether, then we shall perceive that the freezing and boiling points are inverted, i. e. that the freezing-point is the hotter, and the boiling-point the colder of the two, the latter being about 50° below the former.
Euchlorine.—This substance was easily converted from the gaseous state into a solid crystalline body, which, by a little increase of temperature, melted into an orange-red fluid, and by diminution of temperature again congealed; the solid euchlorine had the colour and general appearance of bichromate of potassa; it was moderately hard, brittle and translucent.; and the crystals were perfectly clear; It melted at the tempe-
