134 
when, therefore, according to generally received meteorological 
principles, there would appear to be little probability of a con- 
densation of vapour into the form of rain. 
I cannot conclude this communication without gratefully 
acknowledging the kindness of Mr. Bates, in affording me an 
opportunity of examining his valuable observations which 
form, I believe, the only series of the kind ever yet made. 
PHOTOGRAPHICAL SECTION. 
February . 8th, 1866. 
Dr. J. P. Joule, F. R.S., Vice-President of the Section, 
in the Chair. 
Mr. Sidebotham brought before the section a number of 
pictures, by Boulton and Watt, which had been supposed to 
be photographs. The examination he had made of them 
convinced him that they had been produced by a different 
process. 
Mr. Dancer coincided in this opinion. He thought that 
the camera had been employed, but solely for the purpose of 
enabling the artist to trace the outline, and to enlarge or 
reduce the image to any required scale. The shading would 
be an after process, the crayon employed being made of some 
resinous or fatty substance mixed with the colour. 
March 8th, 1866. 
Dr. J. P. Joule, F.R.S., Vice-President of the Section, 
in the Chair. 
Mr. Brothers, F.R.A.S., stated that since the last meeting 
he had tried the use of wax dissolved in ether, as recommended 
