334 ESSAYS ann.OBSERVA|TIONS 
and -are fucceeded by other acid. particles 
to perform their part of the operation, until 
all the parts of the folvent are equally char- 
ged with particles of filver. 
.TuHeE attractive force between the | olin 
particles of the fpirit of nitre and the filver, 
muft be fuperior to the power by which the 
particles of filver attract one another; for, it, 
diffolves their cohefion, feparates them, and 
keeps them fufpended in a fluid which has 
only about one tenth part of the {pecific gra- 
vity of filver: yet thefe particles, thus fufpend- 
ed, differ in nothing, when freed from the 
acid, but bulk from granulated: filver or the 
bits rubbed ‘off plate by a fine file. © That 
this power’of attraction between the particles 
of fpirit of nitre and: thofe of filver muft 
be very great, will appear, if we confider, 
firft, that it requires a very great heat to melt 
filver; but this melting is nothing elfe, than 
by the force of fire, to overcome the cohefi- 
on among the particles of filver, and bring 
. the mafs'to a ftate of fluidity, fo that the: ‘pare! 
ticles may eafily move and flide one upon an- 
other while that degree of heat lafts;' but 
fpirit of nitre produces the fame or rather a 
ereater effect. In the next place, tho” fpi- 
rit 
