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When this experiment is performed with two black 
flock ings in one hand, and two white in the other, it 
exhibits a very curious fpedlacle : The repulfion of 
thofe of the fame colour, and the attraction of thofe 
of different colours, throws them into an agitation 
that is not unentertaining, and makes them catch each 
at that of its oppofite colour, at a greater diftance than 
one would expedl. When allowed to come together, 
they all unite in one mafsj when feparated, they re- 
fume their former appearance, and admit of the repe- 
tition of the experiment as often as you pleafe ; till 
their eledlricity, gradually wailing, Hands in need of 
being recruited. 
y°. — When they are feparated from one another, 
they lofe their power very foon„ much as the excited 
tube does ; but when they are together, they will re- 
tain it for an hour or two, and longer, when the air 
is in a flate favourable for eledlricity. While they 
are afunder, and any non-eledtric is brought near 
them ; if that non-eledtric is of a broad furface, it is 
with difficulty they are difcharged of their eledlri- 
city j but if the point of any, efpecially of a metallic, 
body, be prefented, they are inllantaneoufly deprived 
of their eledlrical virtue : but if they be in conjunc- 
tion together, they retain their eledlricity with fo 
much obftinacy, that even the fharpefl point of me- 
tal cannot deprive them of it. In this, and in fome 
fhock of their congrefs, appear to me to be obfervations new in 
eledlricity, and to merit attention. They feem to point out a re- 
tentive power of eledlricity, which takes place between eledtrics 
and eledtrics only ; and which, I apprehend, may be found to be 
the caufe of many curious and fingular phenomena. 
Z z 2 
other 
