PREFACE IX 



the whole manuscript, a labour to which I would never 

 have submitted, even if the various engagements which 

 occupied my time had not rendered it impossible. 



I have just alluded to the Swedish Essays as the original ; 

 but the truth is, as I have been credibly informed, and it is 

 a curious circumstance, that Mr. Scheele transmits his com- 

 munications to the Stockholm Academy of Sciences, not in 

 Swedish, but in German, his native language, from which 

 they are translated by some member, in order to be inserted 

 in the Transactions. This may perhaps account for the 

 obscurity of one or two passages of no great moment, which 

 I am obliged to leave as I found them, not being able to 

 clear them up by the help either of the German or the 

 French translation, as it occurs in the Journal de Physique. 

 These passages, which are, I think, not above two in number, 

 I intended to point out to the reader ; but I neglected to 

 note them, and cannot now discover them. 



I have, moreover, made some additions, such as the 

 papers of Mr. Wiegleb and Mr. Meyer, together with those 

 both of the author and of Dr. Crell, which occur at the 

 end of the volume, and are chiefly taken from the most 

 excellent of modern journals. Other sources, too, would 

 perhaps have afforded other additions to the author's dis- 

 coveries and corrections of his opinions ; but, having so lately 

 annexed to Bergmann's Dissertation on Elective Attractions, 

 much of what it would have been proper to observe con- 

 cerning Mr. Scheele's experiments and deductions, as far 

 as I am acquainted with it, I choose rather to refer to that 

 publication, than repeat the same things in the present. I 

 know not whether it can now be necessary to put any 

 reader on his guard against the notions concerning the com- 

 position of heat which run through most of the Essays, and 

 are employed to explain the phenomena of phlogistic pro- 



