338 PHILOSOPHICAL TRANSACTIONS. [ANNO 1783. 



parts; for it is first necessary to find the quantity of phlogiston in each of them, 

 not onlv in general, but according to their various degrees of dephlogistication 

 by each of the acids. In this last particular I cannot assert that I have attained 

 any thing like a certainty, yet I hope what I advance may not be useless to che- 

 mical readers, as it is not altogether groundless, as it contradicts no chemical 

 fact, but, on the contrary, is agreeable to many, and affords a ready solution of 

 all the phenomena. 



Of the absolute quantity of phlogiston in metals. — The proportion of phlo- 

 giston in metallic substances relatively to each other, has been investigated in 

 so masterly a manner by Mr. Bergman, that I lay it down as the ground of my 

 inquiries. After his discovery all that remained was to find the absolute quan- 

 tity of it in any one metal; for then, by an easy calculation, it may be deter- 

 mined in all the rest. The substance I chose for this purpose was regulus of 

 arsenic, as being most capable of dephlogistication by nitrous acid, though not 

 altogether so. From 100 grs. of regulus of arsenic, dissolved in dilute nitrous 

 acid, as already seen, 102 cubic inches of nitrous air and Ware obtained, baro- 

 meter at 30°, thermometer at 60°. I must add, that I made the experiment on 



5 grs. only, so that the calculation relates only to the quantity of air which 100 

 grs. should give. I repeated the experiment three times with the same success. 

 I attempted getting more air from the residuum left by a gentle evaporation, but 

 though fresh spirit of nitre grew red with it, the quantity of air was quite in- 

 considerable. 



Now this quantity of nitrous air contains 6.86 



!• ii- f Rclat.quan. Absol. 



ers. of phlogiston, according; to the calculation "><>grs. ot ofphiogist. quan. 



6 , r ° , b , . T Gold 394 ... . 24.82 



to be seen in my former paper ; and hence 1 copper 31,' 1 9.65 



conclude, that 100 grs. of regulus of arsenic Cobalt 270 17.01 



r o« r ui •* t-u- 1 Iron 233 •••14.67 



contains 6.86 grs. of phlogiston. 1 his regulus Zinc 182 .... 11.46 



was made by Mr. Wolfe, and perfectly bright. Nickel 156 9.82 



. , ,. .. r .1 • ^ Regulus of antimony. . 120 7.56' 



Hence the relative proportion of phlogiston in Ti „ .. .114.. 7. is 



metals being, as found by Mr. Bergman, and Regulus of arsenic 109 6.86 



set forth in the 1 st column of the annexed table, wfercaxj . . . . . . . . . . '74 . . . . 4.56 



the absolute quantity will be as shown in the 2d Bismuth 57 3.59 



. Lead 43 2.70 



column. 



This point being of some importance, Mr. K. endeavoured to ascertain it still 

 further by other experiments, unnecessary to be here repeated. 



Of the affinity of metallic calces to phlogiston. — That inflammable air, or 

 phlogiston, is condensed to a very considerable degree by uniting to any metallic 

 substance, so that its specific gravity is not only equal, but much superior, to 

 that of the metallic earth with which it combines, may easily be concluded from 

 the example of fixed air, which, by uniting to calcareous earth, acquires a spe- 



