Supposing the truth of these principles according to the logic of the French nomenclature, there is no acid to which the term nitrous acid _ought_ to be applied; but as it has been used to signify the acids holding in solution nitrous gas, it is perhaps better still to apply it to those substances, than to invent for them new names. A nomenclature, accurately expressing their constituent parts, would be too complex, and like all other nomenclatures founded upon theory, liable to perpetual alterations. Their composition is known from their specific gravity and their colors; hence it is better to denote it by those physical properties: thus orange nitrous acid, of specific gravity 1,480, will signify a solution of nitrous gas in nitric acid, in which the nitric acid is to the nitrous gas, nearly as 87 to 5, and to the water as 11 to 1. X. The estimation of the composition of the yellow and orange colored nitrous acids given in the following table, may be considered as tolerably accurate, being deduced from the synthetical experiments in the sixth section, compared with the analytical ones. But as in the synthetical experiment, when the acid became green, it was impossible to ascertain the quantity of nitrous gas that passed through it unabsorbed, and as in the analysis the quantity of nitrous gas dissolved by the water at different periods of the experiment could not be ascertained, the accounts of the composition of the green acids must be considered only as very imperfect approximations to truth. TABLE I. _Containing Approximations to the quantities of NITRIC ACID, NITROUS GAS, and WATER in NITROUS ACIDS, of different colors and specific gravities._ +------------------+---+----------+---+--------+-------+---------+ | 100 | | Specific | | Nitric | Water | Nitrous | | Parts | | Gravity | | Acid | | gas | +------------------+---+----------+---+--------+-------+---------+ |Sol. Nitric Acid | | 1,504 | c | 91,55 | 8,45 | — — | |Yellow Nitrous[38]| | 1,502 | o | 90,5 | 8,3 | 1,2 | |Bright Yellow | o | 1,500 | n | 88,94 | 8,10 | 2,96 | |Dark Orange | f | 1,480 | t | 86,84 | 7,6 | 5,56 | |Light Olive‡ | | 1,479 | a | 86,00 | 7,55 | 6,45 | |Dark Olive‡ | | 1,478 | i | 85,4 | 7,5 | 7,1 | |Bright Green‡ | | 1,476 | n | 84,8 | 7,44 | 7,76 | |Blue Green[39] | | 1,475 | | 84,6 | 7,4 | 8,00 | +------------------+---+----------+---+--------+-------+---------+ ‡ = “FOOTNOTE {38}” [38] The blue green acid is not homogeneal in its composition, it is composed of the blue green spherules and the bright green acid. The blue green spherules are of greater specific gravity than the dark green acid, probably because they contain little or no water.