[ 364 ] 
when we confider this, I fay, it will be hard to de- 
termine how great the ffrength of their cohefion may 
be. 
The experiment may be tried with two plates of 
glafs, the one electrified pofitively , the other nega- 
tively. As in that cafe the principle, upon which 
the cohefion of the white with the black filk depends, 
would take place, I make no manner of doubt but 
the effeCt would be the fame. I have not had an op- 
portunity of trying the experiment: but I fhould ex- 
peCt that the two plates would be found to cohere 
with greater force, than I have been able to afcertain 
in the ftockings ; as a contrivance might be made to 
pull them afunder in a direction perpendicular to 
their cohering furfaces. 
The force with which the black and the white 
flocking cohere, is not the only thing remarkable in 
their junction. The folution of that cohefion, and 
the different degrees of tenacity, according to differ- 
ent circumftances, afford fome curious obfervations. 
When the black and the white ltocking are in co- 
hefion with each other, if another pair, more highly 
electrified, be feparated, and prefented to the former 
ft ill in conjunction, the black to the white, and the 
white to the black; in that cafe, the cohefion of the 
firfi pair will be diffolved, and each flocking of the 
fecond, will carry off that of its oppofite colour ad- 
hering to it. If the degree of electricity of both 
pairs be equal, the cohefion of the firft pair will be 
weakened, but not diffolved ; and all the four will 
cohere, forming as it were one mafs. If the fecond 
pair be but weakly electrified, the cohefion of the 
firft pair with one another will be but little impair- 
