THE 



PHILOSOPHICAL MAGAZINE 

 AND JOURNAL. 



I. On the discordant Opinions delivered by the Chemists who 

 gave Evidence on the Trials of the Insurance Question of 

 JSevern, King, and Co. versus the Fire Offices. By M. Ri- 

 CARDo, Esq. 



To Mr. Tilloch. 



Sir, — T OR commenting upon the discordant opinions which 

 were given on the trial of Messrs. Severn and Co. relative to some 

 of the propertiesof oil, and which have been put on record in the 

 last Number of the "Philosophical Magazine, it is unnecessary for 

 me to offer any apology to those gentlemen the correctness of 

 whose doctrines I have presumed to call in question. Opinions 

 upon scientific subjects, or indeed upon any other, which are 

 publicly promulgated, become public property, and are open to 

 the observations and criticisms of any one who chooses to descant 

 upon them ; and in freely canvassing such opinions, it is always to 

 be understood that the doctrines only are criticised and not the 

 persons advancing them; nothing personal is meant : that esti- 

 mation in which, as men of science, they are so highly held, 

 and that respect to which they have become so justly entitled, 

 and which no one feels more warmly than the individual who is 

 now addressing you, are not in the slightest degree lessened by 

 the casual advancement of doctrines which on examination may 

 not be found perfectly tenable. The question at issue, however, 

 is not the truth or falsehood of an hypothesis; but it is as to the 

 existence of facts, facts that no doubt may and will be clearly 

 proved to the satisfaction, or I should rather say to the convic- 

 tion, of all parties. Hypotheses or theories may be disputed, but 

 the facts themselves cannot be disproved ; and whether oil is de- 

 composable below a certain heat, whether it gives out inflamma- 

 ble vapour, and whether it is easily or dillicultly heated, may be 

 as clearly proved, if the trial is made unbiased by party feeling, 

 as any problem in mathematics. 



The observations which I propose to make are upon the evi- 

 dence which was given on the trial, without any reference to ex- 

 periments that may have been subsequentiv made; and I shall 



Vol. r>7. No. 27<'i. Jan. 1821. A 2 com- 



