C *99 3 
communicated to it from the Standard Bar, as mark'd 
on the Brafs Circle by the Index: Let the Inftrument 
(land, till the whole is thoroughly cold j then removing 
the Bar E, lay a Bar of any other Metal in its Place,, 
and heat the Standard Bar to the fame Degree of Heat 
as before, which is feen by the moveable Plates mark- 
ing the fame Degree of Expanfion. Then the Index 
will fhew the Degree of Expanfion of the fecond 
Metal, as it did of the firft; and, by this Means, the 
Degrees of Expanfion of different Metals by the fame 
Degree of Heat, may be exa&ly eflimated. 
i. . — , 
II. A further Account of the Bones of 
Animals being made Red by Aliment 
only. By John Belchier, F. R. S. 
I N the former Account, which I gave concerning the 
Red Bones of the Hogs, (feeN Q 442.y>.286.) Imen- 
tion'd, That the Colour was occafion d by Bran, (being 
mix'd with their common Food) after it had been made 
Ufeofto clean printed Callicoes; the Colours of which 
were made, fome 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 Ufe of 
to fix thefe Colours on the Cloth. To which 
of thefe Preparations the Colofir was owing, I could 
not determine. Some were of Opinion, that it was 
intirely occafion d by the Preparations of Iron 5 others, 
that it was the whole blended together; And, in or- 
Q^q 2 dor 
