Mayer — Experiment* with Pendtihtm-eUdronuier. 381 



Ar the heads of the columns of following t al >K* d Btands for 

 the deflections in em& ; IV for the distances apart of the centers 

 of spheres in cms,; /'. for force in dynes; y, for units of 

 quantity of electricity. 



Til: 

 111. 



9 

 12 

 15 



18 



21 



Tin 

 Om. 



3 

 6 



9 

 12 

 13 

 18 

 21 



The mean loss per minute is y^ of the charge ; and the 

 difference between the maximum and minimum measures is 

 ■g-J-g-. In Coulomb's experiments (Mem. 3 d 1785) this differ- 

 ence amounts to -^-$. 



The loss of electricity, as is well known, follows Newton's 

 law of cooling; and these experiments show the operation of 

 this law very closely. 



The coefficient thus found is, however, only applicable to 

 experiments made in similar hyrometric and barometric condi- 

 tions of the air, fov the coefficient varies with these conditions. 



In the above experiments the barometer was at 30*069 ins. ; 

 the force of vapor "251 ins. ; and the relative humidity 31 "3. 

 Temperature of air, 73° F. 



Experiments on the distribution of electricity on a cylinder, like 

 the one experimented on by Coidomb. 



In his sixth paper, of 1788,* Coulomb gives his measure- 

 ments <»n the distribution of electricity on a cylinder with 

 hemispheric ends. It was 30 French inches long and 2 French 



* Sixieme Memoire sur l'£lectricite, Mem. de 1'Acad. Sci., 1788, p. 628 







_ d 







d 



D 



' ~ -\\\ 



Vf 



grrD^j 



3-10 



510 



9*1176 



3-0 2 



15 -11)20 



8*02 



5*02 



8-8- 



2 98 



[5*9596 



2 94 



•1 94 



i T *> 



294 



11 5236 





1 865 



B-4264 



2 90 



14-1085 



2-7!»7 



■1 7:»7 



V| 



2 B7 



13-7674 



2-73 



4 73 



8-02!) 1 



2-83 



13-3859 



2-67 





7*8529 



2-80 



13*0760 



2 GO 



4-60 



7-0^43 



2-76 



126960 





Dif. and 3: 





Loss 



Loss 



'1 



3 and 6. etc. 



Mean q 



per 3 m. 



per m. 



15--J020 













•4424 



15-1808 





T02 



14 9596 



• 











•4360 



1 17416 



A 



To? 



14-.V23C 













•4151 



14-3160 



■h 



102 



14 1085 













•3411 



139370 



A. 



4 1 



12 3 



13 7GT4 



• 











•3815 



13-5766 



-i-v 



luS 



13-3859 













•3099 



13-2309 



.1- 



49 



17* 



130760 













•3800 



12-8860 



h 



To7 



126960 











