[ 240 j 



EXPERIMENTS, 1773* 



{From MS. N. 14: see Table of Contents at the beginning of this volume. 

 The footnotes refer back to the formal account of results. [ 



494] Spreading of electricity on surface of glass plates. 



4 plates of English glass were cut out of same piece and coated with bits 

 of tinfoil of the same size. One of these plates was covered at different times 

 with thick solution of lac, which ran into heaps in drying, another with trans- 

 parent varnish which also ran into heaps, another with solution of lac and 

 vermilion which lay smooth, and the other left as it was. 



They were all done in the end of the summer and suffered to dry in the 

 open air. The spreading of the electricity on their surface was tried in the 

 manner described 1772, p. 22 [Art. 486]. 



Tu. Oct. 13 [1772]. Th. 63. N. 2o|. C. - 7. 

 D of Nairne, corks closed immediately. 

 G do. in cem. in 3" or 4". 



Plate with lac closed immediately, sep. again in 3" or 4". 

 Lac and verm. D, but much more. 

 Transparent varnish same as lacquer. 

 Plate not varnished closed immediately, sep. again in 5" or 6". 



495] To see whether the machine used for trying Ley den vials f conducted fast. 



The heavy and light paper cylinders being both hung to conducting wire, 

 and globe J turned till heavy ones separated, the light ones closed in i'. i" 

 after the others when the conducting wire communicated with machine, and 

 about i'. 20" when it did not. 



496] The plate covered with solut. lac was undone, and that and the plate 

 not varnished were lacquered in Nairne's manner, one with vermilion, the 

 other without. Neither of them were dried after the operation. 



The old Lac and vermilion and the transparent varnish were dried before 

 fire, heat uncertain. 



Frid. Oct. 16 [1772]. Th. 63. N. 20. C. 10. 



The two plates lacquered in Nairne's manner discharged the electricity of 

 the jars presently. 



Lac and verm, in i 8 ' manner closed in about 10". 

 Transparent varnish uncertain, from 5" to 20". 



* [This is the heading of this bundle of the Journal, though many of the dates 

 belong to 1772.] 

 t [Art. 295.] 

 | FOf electrical machine. See Arts. 248, 563. 568, 569.] 



