The 12,5 cubic inches of undecompounded gas that came over were examined; and accounting for the small quantity of common air previously contained in the airholder, must have been almost pure. _l._ Now supposing 927 grains of the impregnated solution (including the weight of the nitrous gas), to have been operated upon, this must have contained about 16,7 cubic inches of nitrous gas. But 12,5 cubic inches escaped undecompounded: hence 4,2 were decomposed; and these weigh 1,44 grains, and are composed of,8 oxygene, and,64 nitrogene.[117] Consequently, the nitrous gas must have furnished,8 of oxygene to the green oxide of iron. But,64 of nitrogene require,15 of hydrogene to form,79 of ammoniac:[118] consequently 1 of water was decompounded, and this furnished,85 of oxygene to the green oxide of iron. [117] Division IV. Section 5. [118] Division II. Section 1. The green oxide of iron contains ²⁷/₁₀₀ oxygene; the red ⁴⁸/₁₀₀. But the whole quantity of oxygene supplied from the water and nitrous gas is 0,8 + 0,85 = 1,65; and calculating on the difference of the composition of the red and green oxide of iron, 5,7 grains of red oxide must have been deposited, and consequently these would saturate as much acid as,79 grains of ammoniac, or 4,1 grains of green oxide of iron.[119] And supposing the ammoniac in sulphate of ammoniac to be to the acid as 1 is to 3,[120] 3.2 grains of sulphate of ammoniac must have been formed, containing about 2,4 grains acid; and then 6,5 grains of green sulphate of iron must have been decomposed. [119] No precipitation takes place during the conversion of solution of green sulphate into red; and the acid appears saturated. [120] Division II, Section 6. Hence we gain the following equation: 6,5 green s. = 2,41 sul. acid + 4,1 gr. ox. iron. + 1,44 nit. gas = ,64 nitrogene + ,8 oxygene. + 1 water = ,85 oxygene, + ,15 hydrogene, equal 3,2 sul. am. = 2,41 s. acid + ,64 nit. + ,15 hyd. + 5,7 r. ox. iron = 4,1 gr. ox. iron + 1,6 oxyg. Though the estimation of the quantities in this equation must not be considered as strictly accurate, on account of the degree of uncertainty that remains concerning the exact numerical expression of the quantities of the constituents of water, ammoniac, and the other compound bodies employed; yet as founded on a simple quantity, that is, the nitrous gas decomposed, it cannot be very distant from the truth. The sulphate of ammoniac given by experiment, is considerably less than that which was really produced; much of it was probably carried off during the evaporation of the superabundant acid.