454 



R L K C T R I C I T V. 



(). Oi the Distribution of Electricity among xti-eral Globes inchfit 



placed in Contact in a IJne. 



four globes of 2 inches, in contact with a globe of ei^ht 



I-.!..- 



Six jul Rr;i. I . When six equal glo 



ter -. re in OIK- lii. 

 in t! 



in' 2 inches in diame- 

 il, mid then examined 

 the following results : 



> to that ofthcjcrrwfrfns 148 to 100. 

 fthejfarf is to that of the third as 156 to 100. 



Hence, tiie density has been diminished one third 

 from the first globe to the second, and only one fifteenth 

 fn n tiie second to the third. 



F. i/<. 2. When twelve globes 2 inches in diameter were 

 .1 in a row, and examined as before, the electric 



Density of ihejirst is to that of the second Ml. SO to l.OO. 

 Dernitjofthejfr* is to that of the sixth as 1.70 to 1.00. 



8. Distribution ofF. kcfricify on tie Surface if,i Cylind 



er. 



Twcn EJLJI. .'i. When twenty-four equal globes 2 inches in 



wjiul t ii; UUC ter were placed in a row, the electric 



iv of the fint is to that of the second a* 1.56 to 1.00 

 Density of the>Vj/ is to Uiat of the ItvclJUi 



or niitlJlc globe as 1.75 to 1.00. 



It follows from these two experiments, that whatever 

 be the number of globes, the mean density varies con- 

 siderably from the first to the second, but afterwards 

 very s'ow ly, from the second to the middle globe. At 

 equal distances from the extremities of the row, the 

 electric densities are equal, and therefore the density is 

 always least in the middle. 



~. Distribution of Electricity over several unequal Globes. 



)utribu. Exp. 1. When two globes 2 inches in diameter were 

 lion of dec- placed in contact with one of 8 inches, the quantity of 

 tricitr over electricity of the small globe most distant from the 



VI globe,. JJ^J one' J2 S 54to ".00 



Exp. 2. When four globes of 2 inches were placed in 

 contact with one of eight inches diameter, the quantity 

 of electricity of the small globe, the most distant from 

 the great one, was to that of the globe nearest the great 

 one as 3.40 to 1 .00. 



E.rp. 3. When five globes of 2 inches in diameter, 

 were placed beside another of 8 inches diameter, the ra- 

 tio of the density of the fourth globe was to the mean 

 density of the large globe as 2 08 to 1.00. 



I-'.T]>. 4. When twenty-four globes two inches in di- 

 .imeter were placed in contact with one of eight inches, 

 Coulomb compared the twenty-fourth, or the last small 

 globe, with several of the others, and obtained the fol- 

 lowing results : 



The quantity of electricity, or mean density of the elec- 

 tric matter in the 24th globe, is to that of the 23d 

 as 1.49 to 1.00 



The quantity in the 24th is to that of the 



12th as 1.70 to 1.00 



The quantity in the 24th is to that of the 



2d as 2.10 to 1.00 



The quantity in the 24th is to that of the 

 1st, or the one in contact with the large 

 globe, as 3.72 to 1.00 



The quantity in the 24th is to that of the 



large globe itself as 2.16 to 1.00 



This last result differs very little from that which we 

 lve found for the fourth globe, at the end of a line of 



In the following experiments, Coulomb insulated a nistribu- 

 cylinder 31 . ml J inches in diameter ; unil '".'". " f doc - 



having electrified it, he examined its i Wtrkal density Jh^iufto 

 in several places by a small circle ol'^ilt paper as be- ofmryb'n- 

 fore, and obtained the follow ing rc-ults : dw. 



The density of the middle of the cylinder is to that nf 

 its exti entity as ......... ". . . . 1.00 to 



The density of the middle of the cylinder 

 N to tint of a point 2 inches from the 

 extremity as ............... 1.00 to 



The density in the middle of the cylinder 

 i> to that of a point situated in the he- 

 misphere which terminated the cylinder 

 at an inch from its extremity, as .... 1. 00 to 



1 lence it follows, that upon the two last inches at the 

 extremity of the cylinder, the electric den-itv is much 

 greater than towards the middle of the cylinder, and 

 that it varies a little from the middle to within 2 inche* 

 of the extremity. 



9. On the Distribution of Electricity bcltrcen a Globe and 

 ( 'yimdcrs of diffi-rent lengths, but of the same diame- 

 ter. 



Eip. 1. Having electrified a 'globe eight inches in \vhcntlu- 

 diameter, and made it touch an insulated ball nine cylinders 

 lines in diameter, Coulomb found its electrical force have the 

 to be 154% or 150 when corrected for the dissi- "' dia - 

 pation. He then quickly touched the eight-inch globe 

 with the cylinder two inches in diameter, and 30 

 inches long, and upon withdrawing the cylinder, he 

 examined its electricity by the small ball as former- 

 ly, and found it to be 68. Hence 150 of electricity 

 were reduced to fi8 by the contact of the cylinder, 

 which therefore took 82 from the electricity of the 

 globe, leaving it only 6'8. The quantity of electric 

 fluid, therefore, in the cylinder, is to that in the globe 

 as 82 to 68, or as 1.21 to 1.00. Now, the superficial 

 area of the globe is to that of the cylinder as 6'0 is to 

 (J4 ; consequently, the mean density of the electric 



1 '*! 

 matter on the surface of the cylinder, or ~ ', will be to 



60 

 , or as 129 is to 100. This ratio may be stated 



1.00 



~64~ 



more accurately as 1.30 to 1.00, which is the mean of 



a great number of experiments. 



EJ.JI. " When the cylinder was 15 or even 10 inches 

 long, its electricity was divided with a globe of eight, 

 inches in such a manner, that their mean densities 

 were almost exactly in die same ratio of 1.30 to 1.00, 

 as in the preceding experiment. When the diameter of 

 the globe, however, was very large compared with that 

 of the cylinder, and when the cylinder had very little 

 length, then the mean density of the cylinder, relative 

 to that of the globe, was much less than when the 

 length of the cylinder was considerable. 



E.rp. 3. When a small cylinder, five or six lines in 

 length, and two lines in diameter, was put in contact 

 with a globe of eight inches, the mean density of the 

 electric fluid on the surface of the cylinder was to that 

 of the globe nearly in the ratio of two to one ; but 



3 



