On phlogiston. ^i^ 



foib not lefs than 362 ounce meafures of it, or tlie phlo- 

 giilon contained in it. An ounce of lead, I have Ihevvn, 

 takes 108 ounce meafures of this air, an ounce of bifmuth 

 I 85, and an ounce of tin 377 ounce meafures of inflam- 

 mable air ; fo that mercury contains more phlogifton than 

 two of thofe metals ; and notwithftanding this it may be 

 revived in a glafs retort, without any inflammable air at 

 nil. Here is a great difliculty, no doubt ; but it may be 

 folved b)^ fuppofuig that this fubftancc is capable of attraft- 

 ing phlogifton through the hot glafs. And if //g7jf, and bea/, 

 both acknowledged fubj}ances^ can penetrate glafs, why 

 may not phlogifton? This mufl: either be fuppofed, or 

 that an ounce of mercury may either contain all the phlo- 

 gifton in 362 ounce meafures of inflammable air, or none 

 at all, and yet be the fame thing, having all the fame che- 

 mical properties. Let philofophers confider this cafe with 

 impartiality, and form the bell theory that they can to ac- 

 count for the fads. Though fo much flrefs has been laid 

 on the experiment with this calx of mercury, as a founda- 

 tion for the new theory, it is by no means conclufive in its 

 favour. 



Had the publication of your Tranfacftions been more 

 frequent, I Ihould with mucli pleafure have fubmitted to 

 the fociety a full account of thefe and other experiments, 

 which appear to me to prove, that metals are compound 

 fubftances, and that water has not yet been decompofed by 

 any procefs that we are acquainted with. Still, however, 

 I would not be very pofitive, as the contrary is maintained 

 by almoft all the chemifts of the age, and therefore their 

 hypothefis requires to be confidered with the greateft at- 

 tention. This 1 Ihall continue to give to it ; and certainly 

 it is high time to decide this queftion ; fince a great part of 

 the fyftem of chemiftry depends upon it, and a falfe theory 

 anay retard the progrefs of this important branch of fcience. 

 3 E Wifhing 



