EADIATION OF HEAT BY GASEOUS MATTEE. 
83 
effect. As regards the absorption of radiant heat, the perfume of a flower-bed may be 
more efficacious than the entire oxygen and nitrogen of the atmosphere above it. 
After each scent had been introduced a stream of dry air was admitted at one end of the 
tube, while the pump was worked in connexion with the other. The perfume was thus 
cleared out until the needle returned to 0°. This was often a long operation, the odours 
clung with such tenacity to the apparatus. After the zero had been attained in the 
case of a strong perfume, a few minutes’ rest of the pump sufficed to bring the scent from 
its hiding-places in the cre’vices and cocks of the apparatus, and almost to restore the 
original deflection. The quantity of those residues must be left to the imagination to 
conceive. If they were multiplied by billions they probably would not reach the density 
of the air. 
Fearing that the more active perfumes might possibly prejudice the action of the 
more feeble ones which succeeded them, I made a series of experiments with the follow- 
ing: essences, and obtained the results recorded : — 
Camomile flowers .... 87 
Spikenard 355 
Aniseed 372 
After this enormous effect I repeated the experiment wdth bergamot, and found its 
action to be exactly the same as that recorded in the Table. 
I made a few experiments on musk, but obtained different results with it at different 
times. On the 16th of October I obtained some fresh musk from the perfumer’s, placed 
it in a small glass tube, and earned dry ah’ over it into the experimental tube. The 
first experiment gave me an absorption of 
74, 
the air which earned the perfume being unity. A second experiment, in which the air 
was admitted more quickly, the absorption was 
72. 
It would be idle to speculate upon the quantity of matter which produced this result. 
The stories regarding the unwasting character of this substance are Avell known ; suffice 
it to say, that a quantity of its odour carried into the tube by a current of air of a minute’s 
duration, produced an effect seventy-two times that of the ah which carried it. Long- 
continued pumping failed to cleanse the tube and passages of the musk. It cannot be 
volatile, for an amount of ether vapom* which produces a far greater action is speedily 
cleared away, while the cocks and connecting pieces of the air-pump had to be boiled 
in a solution of soda before they were fit for use after the experiments with this sub- 
stance. 
Two perfectly concurrent experiments with ordinary cinnamon, in which fragments 
of the substance were placed in a tube and had dry air passed over them, gave an 
absorption of 
53 . 
