4 
Ordinary Meeting, October 17th, 1882. 
H. E. Roscoe, Ph.D., LL.D., F.R.S., &c., President, in the 
Chair. 
“On the Development of Living Germs in Water,” by 
Dr. R. Angus Smith, F.R.S. 
An abstract of this paper will appear in a succeeding 
number of the Proceedings. 
Mr. William H. Johnson, B.Sc., in the absence of Mr. 
Leader Williams, C.E., gave an explanation of the plans 
of the proposed Manchester and Liverpool Ship Canal. 
“ On the Formula for the Intensity of Light transmitted 
through an Absorbing Medium, as deduced from Experi- 
ment,” by James Bottomley, B.A., D.Sc. 
In a former communication, an experimental method was 
suggested for testing the validity of an assumed law of 
intensity of light that has passed through an absorbing 
medium. The method was this : take two surfaces of 
different degrees of brightness, survey them through some 
absorbing medium, adjust the lengths of the columns so that 
the intensities shall be the same ; then, if the law of absorp- 
tion be true, the intensities will again be equal if both 
columns are increased by the same length. Some experi- 
ments which I made gave results in agreement with the 
theory. In these experiments surfaces of different degrees 
of whiteness were observed through a grey solution. The 
error arising from the finite extent of the surface is small, 
and the mean intensity which we observe may be taken as 
the intensity of the central ray. 
