162 ON A SYSTEM OF NOTATION ADAPTED TO EXPLAINING 
- 
the plate away from the book, the 2 V of the face acts again by 
ind é 
thus capable of giving a positive spark. As a matter of fact, this 
last positive charge is much stronger than that obtained when the 
— after friction is raised and the back brought to an electro- 
scope ; and much stronger also than the negative charge got from 
the back when the plate and book are raised together. A glance 
at the notation shows clearly the reason of this. 
Turn now to the function of the machine in charging a Leyden 
jar. In applying our notation we have to consider four separate 
chai h 
insulated rubber. On eac ese parts w kan represent the 
neutral electric fluid as R a Vv, and we then hav 
Leyden as 
a a P. Cond. Inside. | Outside. 
Vv R+VIR4+V 
8 
notation. But at thre A pope 8, namely, between glass of machine 
and P.P.C., between P.. side of jar, and between out- 
Machine Air. es ‘i ose Air. Inside. Glass Outside. 
RV 
as MS + 
The slide fluid formed at these three points must be instantly 
redistributed on the neighbouring surfaces, one half gomg one 
way the other half the other way. We then etn ve— 
Machine. 
iat ac ey PRE) 4M 
rer yLyY | EFT ET 
Every has thus eer the same measure of e 
finid as when we iis machin and PP. the Bu 
neutral ; bu ac ie ok the there is an excess 
| RR” V++to rubber. ; 
