i a 
MEMOIRS 
OF THE 
LITERARY AND PHILOSOPHICAL SOCIETY 
OF MANCHESTER. 
I. — On the Composition and Derivation of Rosolic Acid. 
By R. Anecus Suiru, Pu. D., F.R.S. 
Read December Ist, 1857. 
Wuen engaged in making an examination of ammoniacal 
liquor from the Manchester Gas Works, I found that a 
solution, from which the sulphur united with the ammo- 
nium had been removed, became, after a week or two, of a 
very beautiful rose colour. The amount of substance 
necessary to produce this colour in a portion of liquid con- 
tained in a beaker glass, was extremely small, scarcely 
capable of being seen, much less of being examined care- 
fully. To have made use of portions of the gas water 
sufficiently large to obtain enough for examination would 
have required operations of very inconvenient magnitude. 
Some time after this, in 1855, Mr. Mc. Dougall found 
that the lime which was exposed to the currents of certain 
vapours in his works became red. These vapours arose 
VOL. XV. B 
