190 
Manchester alone offers no opportunity of the kind. The 
continued postponement of the promised development of 
the Museum constitutes, in the opinion of the Section, a 
grave departure from the spirit of the late Nat. Hist. 
Society’s generous gift.” 
PHYSICAL AND MATHEMATICAL SECTION. 
Annual Meeting, April 27th, 1880. 
E. W. Binney, F.R.S., F.G.S., President of the Section, 
in the Chair. 
The following gentlemen were elected Officers of the 
Section for the ensuing year : — 
E. W. BINNEY, .E.S., P.O.S. 
JOSEPH BAXENDELL, P.E.A.S. 
ALFEED BEOTHEES, E.E.A.S, 
JAMES BOTTOMLEY, D.Sc., B.A. 
: 
EE'V. THOMAS MACKEEETH, F.E.A.S., E.M.S. 
“Colorimetry, Part V.,” on the Absorption of Light by 
Turbid Solutions, by James Bottomley, D.Sc. 
Media containing colouring matter may be divided into 
two classes, transparent and turbid. It might be considered 
tliat in tlieir behaviour with regard to light they were 
wholly dissimilar. But the question arises, is not the differ- 
ence between tran.sparency and turbidity one of degree. 
