92 REPORT—1845. 
of inquiry. First of all permit me to state the reasons which induced me to 
undertake that series of investigations, the principal results of which will form 
the substance of my communication. 
The peculiar smell developed during electrical discharges and the pecu- 
liar odour disengaged by lightning, have been the subject of a good deal 
of conjecture; but as far as I know, philosophers have not yet succeeded in 
clearing up the nature of that smell. The obscurity in which that phe- 
nomenon is enveloped, and the fact, I think first stated by myself, that on elee- 
trolysing water an odour makes its appearance very like to that called the 
electrical smell, excited my curiosity so much the more, that the circumstances 
under which the two sorts of smells are produced are apparently so very 
different from each other. 
I made up my mind to investigate the subject as closely as possible, and in 
spite of its peculiar difficulty and many fruitless endeavours, 1 succeeded at 
last in ascertaining some facts which seemed to open a path for further and 
accurate inquiry. 
These facts were,—1, that the odoriferous principle developed during 
the electrolysis of water is only disengaged at the positive electrode; 2, 
that the same principle may be preserved in well-closed bottles for any length 
of time; 3, that this principle polarizes negatively gold and platinum; 4, that 
the odoriferous substance is destroyed by heat and a number of oxidizable 
bodies; 5, that the electrical brush has the same odour as the oxygen dis- 
engaged at the positive electrode; 6, that the brush has the power of polar- 
izing negatively gold and platinum; 7, that on heating the points out of 
which electricity is passing into the atmosphere, they no more develope the 
electrical smell. From these and some other facts, I was inclined to infer that 
the electrical brush produces the same principle which is disengaged at the 
positive electrode during the electrolysis of water, and as chlorine, with regard 
to its voltaic bearings, acts very similarly to this odoriferous principle, I sus- 
pected the latter to be a body analogous to chlorine. To decide on the cor- 
rectness of that conjecture, there seemed to be no other way left open than 
to isolate the principle in question; but considering the infinitely small 
quantities in which the odoriferous substance is produced under the cir- 
cumstances mentioned, the carrying into effect that isolation assumed the 
appearance of a thing lying beyond the reach of possibility. Yet after many 
trials undertaken with a view of producing more abundantly and by other 
than electrical means, my peculiar principle, I succeeded at last in doing so, 
and phosphorus proved to be the substance most convenient to obtain that 
end. And from the discovery of the most remarkable action which that body 
under certain circumstances exerts upon common air, I was led to ascertain 
the whole series of the curious and rather surprising facts Iam about to state, 
and to arrive, if not at the complete solution of my problem, at least at the 
opening of the path which will ultimately lead to that goal. 
And now I am touching upon that part of my report which, as to its mat- 
ter of fact contents, is the more interesting one of the whole of the commu- 
nication I have to make to you, and I beg leave to call your attention to the 
following statements :— 
1. If at a temperature of 32° a piece of phosphorus, having a clear surface, 
be placed in a bottle filled with common air, a peculiar smell makes its ap- 
pearance which is considered to be due to the vapour of phosphorus; at the 
same time that the included air assumes the power of polarizing positively a 
plate of platinum or gold which happens to be brought in contact with it. 
2. Everything remaining in the state indicated, except the temperature 
being raised to about 60°, a change will very soon take place both with re- 
