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IX. Experiments on a new Colouring Subjlance from the 
IJland of Amflerdam in the South Sea. Made by Mr, 
Peter W oulfe, F, R. S. at the Eefire of Sir John Pringle, 
Bart, P. R, S. 
Redde, Feb. 2, ^ ' | fubftaiice is of a light bright orange 
A colour; has a peculiar, though not a 
ftrong, fmell ; and, when handled, gives a yellow ftaiii 
to the fkin, which does not readily wafli out with foap 
and water. Put on a red hot iron, it fmoaks, melts, 
and catches fire, leaving a caput mortuum. When boiled 
with water, it gives the liquor only a flight yellow tinge, 
which is but little heightened by the addition of a fixed 
alkaly ; therefore the colouring part of this fubftance is 
infoluble in water. Oil of vitriol put to it becomes of a 
red orange colour ; but, when the acid is drained off, the 
refiduum appears purple. Annotto, treated in the fame 
manner, gives a blue colour. Spirit of wine, aether, 
fixed and volatile alcalies, as alfo foap, difiblve the co- 
louring part of this fubftance. To determine the 
quantity of colouring matter which it contains, two 
drams were digefted in a mattrafs, with four ounces of 
redlified fpirit of wine; the folution being filtered af- 
fumed a rich deep yellow colour, like a ftrong folution 
of faffron or gumbouge with the fame fpirit ; what re- 
Vo L. LXY. O mained 
