6. The calcined residue being placed in muriatic acid, a solution now took place both of the lime and of the alumine, and there remained at the bottom of the vessel only an insoluble portion of pure silex, in the form of a white powder, which when carefully washed and dried weighed of a grain. Deducting therefore this weight of the silex, from the weight of the silex and alumine, which remained in No. 4, after the combustion of the bitumen, the weight of the alumina is ascertained; which of course equals 8, grains.
From all the preceding observations, it is therefore evident that the constituents of this limestone are as follow:
| Lime | 49. | 65 |
| Carbonic acid | 40. | 10 |
| Alumine | 8. | 80 |
| Silex | — | 60 |
| Bitumen | — | 60 |
| Water | — | 25 |
| ───────── | ||
| 100. | — | |
And the valuable property of the mortar prepared from this limestone, is owing to the presence and proportion of alumine; and to its property of rapidly absorbing water.
