Page:Experimental researches in chemistry and.djvu/77

62 the equivalent number for nickel to be 28, these quantities are equal to—

Supposing the quantities to be correctly

the proportions per cent. are,—

A second experiment on 47 grains gave 61 grains of peroxide of iron =42.57 iron. The ammoniacal solution of nickel was lost by an accident; reckoning from the iron, the quantities per cent. are,—

A third experiment on 56 grains gave 73.06 grains peroxide of iron=50.99 iron, and 5.4 of oxide of nickel=4.51 nickel; or per cent.,—

The mean of the three gives 8.96 per cent. of nickel.

The meteoric iron was dissolved in aqua regia, and the iron,thrown down by pure ammonia, well washed, and heated red.

In the first experiment the ammonia cal solution was evaporated to dryness, the ammonia driven off by heat, and the oxide of nickel re-dissolved in nitric acid and precipitated by pure potassa, the mixture being boiled a few seconds.

In the third experiment the nickel was thrown down from the ammoniacal solution at once by pure potassa. The first method is best, for a minute portion of oxide of nickel escaped precipitation in the last experiment, to which the loss is probably to be attributed.

All the precipitates were heated to redness.

J. G. C.