Mr. Faraday on the Condensation of the Gases, &c. 521 
subsist with the original analytical conditions, however they 
may be modified under the proposed hypothesis; but we can 
neither deny, nor affirm, that other values may also subsist 
with these conditions; for ‘this is information which the ana- 
lytical result is quite incompetent to supply,” and which must 
be derived solely from ascertaining the effect of the proposed 
hypothesis upon the original analytical restrictions; and that 
this is a fair and legitimate deduction from the foregoing ex- 
amination, I think no person who enters into it with unbiassed 
judgement, will be disposed to deny. 
Belfast, May 7th, 1836. 
LXXXIX. On the History of the Condensation of the Gases, 
in reply to Dr. Davy, introduced by some Remarks on that 
of Electro-magnetic Rotation. By Micuart Farapay, 
Esq., D.C.L. F.RS., §c., in a Letter to Richard Phillips, 
Esq., F.RS. L.& E., &c. : 
My pear Sir, Royal Institution, May 10, 1836. 
| HAVE just concluded looking over Dr. Davy’s Life of his 
brother Sir Humphry Davy. In it, between pages 160 
and 164 of the second volume, the author links together some 
account, with observations, of the discovery of electro-magnetic 
rotation, and that of the condensation of the gases, concluding 
at page 164 with these words: “I am surprised that Mr. Fa- 
raday has not come forward to do him [Sir Humphry Davy] 
justice. As I view the matter, it appears hardly less necessary 
to his own honest fame than his acknowledgement to Dr. 
Wollaston, on the subject of the first idea of the rotary mag- 
netic motion.” 
I regret that Dr. Davy by saying this has made that neces- 
sary which I did not before think so; but I feel that I cannot 
after his observation indulge my earnest desire to be silent on 
the matter without incurring the risk of being charged with 
something cpposed to an honest character. ‘This I dare not 
risk ; but in answering for myself, I trust it will be understood 
that I have been driven unwillingly into utterance. 
Dr. Davy speaks of electro-magnetic rotation, and so also 
must I, for the purpose of showing certain coincidences in 
dates, &c. between the latter part of that affair and the con- 
densation of chlorine and the gases, &c. Oersted’s experi- 
ments were publised in Thomson’s Annals of Philosophy for 
October 1820, and from this, I believe, was derived the first 
knowledge of them which we had in this country. At all 
events it was the first intimation Sir Humphry Davy and I had 
of them, for he brought down the Number into the laboratory 
on the morning of its appearance (October Ist) and we re- 
