252 "Journal of Experiments, Dec. 30, 1772 



not appear that it wanted so much, and it seemed as if the outside did not 

 want anything of touching, so that the above measures seem pretty just. 



The diameter of the coating was 11-4. 



The above coatings were taken off from these plates of glass, and coatings 

 6-254 in diameter put in their room, these with the small wax supports placed 

 between them is called plate air 5. 



N.B. 8 folds of the tinfoil used for these coatings was found to be ^ inch 

 thinner than the same number of folds of that used for former coatings, so that 

 this plate air is about -003 thicker than plate air 4. 



The coatings were also taken from thin rosin and coatings 4-525 put in their 

 room. 



A plate of pure lac was also pressed out -125 thick, and the coatings used 

 before for thin rosin put on, which were found at a medium 4-23 in diameter. 



Two plates of dephlegmated * bees wax pressed out the year before were 

 also coated. 



N.B. The bees wax was heated very hot in dephlegmating, and melted with 

 gentle heat when cast into plates. 



The thickness of the A . ' of these plates was , and the diameter of 

 thickest -303 



their coatings ^ . 



518] Lac plate and 4 th rosin compared with D + E + F; also thin wax with 

 E + F; also thick wax and plate air 5 with D. 



Mon. Jan. 4 [1773]. Th. 51. N. 17. 



[23 observations.] 



By these exper. Lac plate contains i inc. el. more than D + E + F; 4 th 

 rosin from 3 inc. more to 2 inc. less, by mean much the same as D + E + F; 

 thin wax 4 inc. less than E + F ; thick wax 2} less than D ; plate air 5 J more, 

 and I st made rosin J more. 



In the preceding experiments the plates of rosin &c. were exposed to the 

 heat of the fire during trials, which seemed to cause an irregularity. To avoid 

 that, in the following days' experiments the plates were laid on table at same 

 distance from fire as the machine for some time before they were tried, and a 

 screen was placed between all of them (except plate air) and fire while trying. 



519] Lac and 4 th rosin with D + E + F; also thin wax with D + E; also 

 thick wax, 2 od rosin and i 8 ' made rosin and plate air 5 with F. 



Tu. Jan. 5 [1773]. Th. 50. N. 17. 



[22 observations.] 



By these exper. 4 th rosin contains from 2 inc. more to 2\ less than D + E + F; 

 by mean, the same as D + E + F. 



Lac from 4 more to \ less, by mean 2\ more than D + E + F. 



Thin wax from 4 less to i less, by mean 2\ less than D + E. 



* [Art. 375.] 



