_Binary Proportions of OXYGENE and NITROGENE in
NITRIC and NITROUS ACIDS._[40]
+---------------+---+-------+--------+-------------+-------+-------+
| 100 Parts | |Oxygene| Nitro- | | Nitro-|Oxygene|
| | | | gene | | gene | |
+---------------+---+-------+--------+-------------+-------+-------+
|Nitric Acid | c | 70,50 | 29,50 | | 1 | 2,389 |
+---------------+ o +-------+--------+ +-------+-------+
|Bright yellow | n | 70,10 | 29,90 | | 1 | 2,344 |
| Nitrous | t | | |Proportions. | | |
+---------------+ a +-------+--------+ Nitrogene. +-------+-------+
|Orange coloured| i | 69,63 | 30,37 | Unity. | 1 | 2,292 |
+---------------+ n +-------+--------+ +-------+-------+
|Dark Green | | 69,08 | 30,92 | | 1 | 2,230 |
+---------------+---+-------+--------+-------------+-------+-------+
[40] Nitrous gas contains 44,05 Nitrogene, and 55,95 Oxygene, as has
been said before.
XI. I have before mentioned that dilute nitric acids are incapable of
dissolving so much nitrous gas in proportion to their quantities of
true acid, as concentrated ones. During their absorption of it, they
go through similar changes of color; 330 grains of nitric acid, of
specific gravity 1,36, after 50 cubic inches of gas had been passed
through it, became blue green, and of specific gravity 1,351. It had
gained in weight but 3 grains; and when the nitrous gas was driven
from it by heat into a water apparatus, but 7 cubic inches were
collected.[41]
From the diminution of specific gravity of nitric acid by combination
with nitrous gas, and from the smaller attraction of nitric acid for
nitrous gas, in proportion as it is diluted, it is probable that the
nitrated acids, in their combinations with water, do not contract so
much as[42] nitric acids of the same specific gravities. The affinities
resulting from the small attraction of nitrous gas for water, and its
greater attraction for nitric acid, must be such as to lessen the
affinity of nitric acid and water for each other.
[41] A great portion of it, of course, dissolved in the water with the
nitrous acid carried over.
[42] Their changes of volume, corresponding to changes of temperature,
most probably, are likewise different.
Hence it would require an infinite number of experiments to ascertain
the real quantities of acid, nitrous gas, and water, contained in
the different diluted nitrous acids; and after these quantities were
determined, they would probably have no important connection with the
chemical arrangement. As yet, our instruments of experiment are not
sufficiently exact to afford us the means of ascertaining the ratio in
which the attraction of nitric acid[43] for water diminishes in its
progress towards saturation.
[43] Probably in the ratio of the square of the quantity of water
united to it.
The estimations in the following table, of the real quantities of
nitric acid in solutions of different specific gravities, were deduced
from experiments made in the manner described in section VI, except
that the phial employed was longer, narrower, and graduated to half
grains. The temperature, at the time of combination, was from 40° to
46°.