Ps.) . m 
; j 
2 ; 
—_ he nn 
beaea oe 
‘h hil. Trans. 18: 
it was Fenner to maccnaiitl series 2, by an exact method; and 
hecessary to calculate all the new aud improved results of series 3. 
_ ‘This the author has now done, by means of Sir W. R. Hamil- 
~ ton’s formula, and for the sake of uniformity has included series 1. 
The results agree perfectly with observation, except in the most 
. highly dispersive cases. But here it is found that if an empirical 
change be allowed in one of the constants for each we pe a 
sufficiently close accordance is obtained. 
Prof. Powell also communicated a paper on the refraction of 
heat, and one on ceriain points of the Wave Theory of Light. 
Prof. Whewell gave an abstract of a Report on the present 
state of our theoretical and experimental knowledge of the laws 
of Conduction of Heat, by Prof. Kelland.—The problem, in the 
solution of which consists the mathematical theory of heat, is the 
following :—Having given the state of heating, or the variation 
of that state from time to time, at one or more points of a homo- 
geneous body of given form and dimensions, to find the perma- 
nent or variable temperature at every other point. Thus a ring 
is kept at a certain temperature at one point, and it is proposed to 
discover: 1. What is the variation from time to time of the tem- 
perature-at every other point. 2. What is the ultimate tempera- 
tee to mhioh: that, ~ SBF given. aot approaches, as the time 
is s increased. From this statement it will appear that the. experi- 
facts on which the theory must rest, are the answers to 
the following questions... 1. According to what law does a heated 
body lose its temperature to the air, or other medium or space, by 
which it is surrounded? 2. According to what law is the tem- 
perature transmitted from point to point of a body? On the cor- 
reetness of the answers which may be assumed as given to these 
- Questions, depends the applicability of the results obtained to the 
State of things in nature. ‘The Report then proceeded to show 
What answers have been given to the above questions by different 
theorists, and to explain the evidence on which their truth was 
sapposed to be established. 
On the temperature of the Air in York Minster, by Prof. 
Phillips. It may be remarked that the vastness and loftiness of 
the interior of York Minster renders the air within it, in a great 
», free from violent sont idranghts, and yet subject to a con- 
‘Vol, gus, No. 1.—Oct.-Dec. 184 
