A Further Account of the Bones of Animals Being Made Red by Aliment Only. By John Belchier, F. R. S.

communicated to it from the Standard Bar, as mark'd on the Brass Circle by the Index: Let the Instrument stand, till the whole is thoroughly cold; then removing the Bar E, lay a Bar of any other Metal in its Place, and heat the Standard Bar to the same Degree of Heat as before, which is seen by the moveable Plates marking the same Degree of Expansion. Then the Index will shew the Degree of Expansion of the second Metal, as it did of the first; and, by this Means, the Degrees of Expansion of different Metals by the same Degree of Heat, may be exactly estimated. II. A further Account of the Bones of Animals being made Red by Aliment only. By John Belchier, F. R. S. In the former Account, which I gave concerning the Red Bones of the Hogs, (see No. 442. p. 286.) I mention'd, That the Colour was occasion'd by Bran, (being mix'd with their common Food) after it had been made Use of to clean printed Callicoes; the Colours of which were made, some from Preparations of Iron, which were the Blacks and Purples; others from Preparations of Alum, and Sacc. Saturni, which produces the Red Colours; and that Madder Root was made Use of to fix these Colours on the Cloth.—To which of these Preparations the Colour was owing, I could not determine. Some were of Opinion, that it was entirely occasion'd by the Preparations of Iron; others, that it was the whole blended together.: And, in or- der to clear up this Point, I determin'd to make some Experiments. The first I made was upon a Cock, by mixing some of the Madder Root with Fig Dust, on which they feed.—The Cock dying within sixteen Days after his first feeding on the Madder, I dissected him, and examin'd the Bones, not in the least Expectation of finding them ting'd in so small a Time; but, to my great Surprize, found them universally of a Red Colour: So that, from this Experiment, it appears, that the Madder alone causes this Alteration: But why the Bones only are affected, I shall consider of in the Course of more Experiments. III. The