318 
REPORT— 1854. 
of luminiferous and calorific rays, are not perhaps expressed with that clear¬ 
ness which might be wished. 
The subject of Section VI.is “on the Sources of Heat;” which is further 
explained to relate to the differences in the nature of the rays, or in general 
the heterogeneity of the rays, entitled from one and the same source at the 
same time; and the differences in this respect, of different sources. 
From the previous experiments the author concludes in general, that “the 
variety of the rays of heat emitted is greatest with the Argaud lamp, less 
w ith red-hot platinum, still less w hen the flame of alcohol is used, and has 
entirely disappeared with the cylinder heated to 212° F." (426). 
But he now' proceeds to test and extend such conclusions in another way, 
viz. by the differences exhibited by the rays in the different action ofdia- 
thermanous bodies upon them, according as they have in the first instance 
passed through certain diathermanous bodies, or proceeded direct from the 
source. The differences thus exhibited give increasing proofs of hetero¬ 
geneity. 
And one more important, point belonging to this inquiry be investigated, 
by platinum heated to successive stages, (lj below 234°, (2) at a red, (3)at 
a yellow, and (4) at a white heat; while in each case the heat was reflected 
diffusely by various surfaces, and in every instance intercepted by the same 
series of screens. (Tables LIf. to LV.) 
from these he draws the conclusion, that the differences which the rays 
evolved at the successive stages exhibit after diffuse reflexion, ou trans¬ 
mission through diathermanous media, are in every instance greater at the 
singe (4) than at (3); these greater than at (2), and these than at (!)• 0/ 
in general, that the heat emitted by platinum at these successive stages is 
successively more heterogeneous as we advance from the lower to the higher. 
Again, with the same body it is not in the mere proportion of the incre^c 
of temperature, ns such ; nor in different bodies does it follow any proportio 11 
to the temperature (as before observed). 
1 he author hints generally at the relation between these degrees of hetero¬ 
geneity and the differences in the nature of the luminous rays emitted; hut 
without laying down any very precise or clearly drawn distinctions as to their 
characteristic properties. 
Truns mission of Heat through Crystals. 
