G3 
Ordinary Meeting, January 11th, 1876. 
Edwakd Schctnck, Ph.D., F.P.S., &c.. President, in the 
Chair. 
“ !N ote on a Method of Comparing the Tints of Coloured ‘ 
Solutions,” by J. Bottomley, D.Sc. 
In the last number of the Chemical News, January 7th, 
is a letter from Mr. Thos. P. Blunt, M.A., proposing a new 
method of ascertaining the quantities of bodies in solution 
by colorimetrical experiments. To two cylinders containing 
equal columns of the fluid to be examined for a certain sub- 
stance he adds measured quantities of that substance, adding 
more of it to one cylinder than to the other ; he then pur- 
poses to shorten the darker column until it corresponds in 
depth of tint with the other, then from the length of the 
two columns he calculates the quantity of the substance 
originally present. At the end of his letter, alluding to the 
method for shortening the column, he states “ The appro- 
priate apparatus mentioned above so far as I am aware is 
still a thing of the future.” Mr. Blunt’s suggestion with 
slight variation may be practically carried out as follows : — 
Take two cylinders of equal diameter; inside, at the 
bottom of each, place a white porcelain disk (the flat lid of 
a crucible will do). In these cylinders let there be equal 
columns of fluid. In one cylinder, which may be called A, 
let a tint be produced by a known quantity of the substance 
sought. Suppose B to contain this substance, and first sup- 
