II 
Meeting was held under the presidency of Mr. Walter 
Baily, M.A., a Vice-President, in the absence, through 
illness, of the President, Sir Richard Temple, Bart. 
The Report of the Council was read and adopted. Sir 
Richard Temple, Bart., was elected President for the 
year 1902, and the officers and Council were also elected. 
Dr. Lindsay Johnson, F.R.C.S., gave an address 
entitled ‘A Century’s Progress in Colour Photography 
and the Knowledge of Colour Vision.” 
Friday, 7th February, 1902, Sir Samuel Wilks, 
Bart., M.D., F.R.S., a Vice-President, in the Chair. 
Mr. Walter Baily, M.A., gave a lecture entitled 
“The Zero of Temperature,” illustrated by experiments. 
The lecturer said that the position of the zero of tem- 
perature, at which there would be absolutely no heat, 
had been known for many years, but had attracted little 
attention until quite recently, when the great advance in 
obtaining low temperature had caused this point of 
absolute cold to be nearly reached. Liquids, such as 
mercury, alcohol, or ether, were conveniently used. in 
thermometers to determine temperatures, but they could 
give no standard scale of temperature, as they expanded 
irregularly, and the laws of their expansion were not 
understood. As to gases, the expansion with temper- 
ature was always the same under constant pressure, 
whatever gas was used, and the size of a certain quan- 
tity of gas was in proportion to the quantity of heat in 
it. Hence, in a gas, the size was the measure of heat, 
and might be properly taken as the standard measure of 
temperature. The construction of a gas thermometer 
was explained, and an experiment was shown in which 
the volume of a certain quantity of air was observed at 
two different temperatures, from which the lecturer ex- 
plained how the absolute zero could be calculated. This 
was 273 degrees centigrade below freezing point of water 
(-460 F.). A diagram was shown, representing a ther- 
