To ascertain the quantities of ammoniac, such as exists in the aëriform state, saturated with moisture, in solutions of different specific gravities, I employed the apparatus for absorption so often mentioned. Thermometer being 52°, the mercurial airholder was filled with ammoniacal gas, and the graduated phial, containing 50 grains of pure water, connected with it. During the absorption of the gas, the phial became warm. When about 30 cubic inches had been passed through, it was suffered to cool, and weighed: it had gained 5,25 grains, and the fluid filled a space equal to that occupied by 57[68] grains of water.
Consequently, 100 grains of solution of ammoniac in water of specific gravity,9684 contain 9,502 grains of ammoniac.
The apparatus being adjusted as before, 50 grains of pure water were now perfectly saturated with ammoniac. They gained in weight 17 grains, and when perfectly cool, filled a space equal to 74 of water. Consequently 100 grains of aqueous ammonial solution of specific gravity,9054 contain 25,37 grams of ammoniac.
The two solutions were mingled together; but no alteration of temperature took place. Consequently the resulting specific gravity might have been found by calculation.
On mingling a large quantity of caustic solution of ammoniac with ¼ of its weight of water, of exactly the same temperature, no alteration of it was perceptible by a sensible thermometer.—Hence the two experiments[69] being assumed as data, the intermediate estimations in the following table, were found by calculation.
TABLE IV.
Of approximations to the quantities of AMMONIAC, such as exists in the aëriform state, saturated with water at 52°, in AQUEOUS AMMONIACAL SOLUTIONS of different specific gravities.
| 100 Specific Gravity. | Ammoniac. | Water. | |
|---|---|---|---|
| 9054 | 25,37 | 74,63 | |
| 9166 | 22,07 | 77,93 | |
| 9255 | 19,54 | 80,46 | |
| 9326 | c | 17,52 | 82,48 |
| 9385 | o | 15,88 | 84,12 |
| 9435 | n | 14,53 | 85,47 |
| 9476 | t | 13,46 | 86,54 |
| 9513 | a | 12,40 | 87,60 |
| 9545 | i | 11,56 | 88,44 |
| 9573 | n | 10,82 | 89,18 |
| 9597 | 10,17 | 89,83 | |
| 9619 | 9,60 | 90,40 | |
| 9684 | 9,50 | 90,50 | |
| 9639 | 9,09 | 90,91 | |
| 9713 | 7,17 | 92,83 | |
As yet no mode has been discovered for obtaining gases in a state of absolute dryness; consequently we are ignorant of the different quantities of water they hold in solution at different temperatures. As far as we are acquainted with the combinations of ammoniac, there is no state in which it exists so free from moisture, as when aëriform, at low temperatures.
That no considerable source of error existed in the two experiments, is evident from the trifling difference between the estimations of the quantities of real ammoniac, in the solution of,9684, as found in the first experiment, and as given by calculation from the last.