PHYSICAL anv LITERARY 32 
the refplendent white colour of unpolifh- 
ed filver. 
19. AFTER 
fight; If the experiments are made with candle-light, 
they are diftinguifhed by the fhadowy or luminous rings’ 
which they project on the bottom of the veffel, according 
as they are convex or concave, 
Some writers have been fo inattentive as to afcribe the: 
motions in the frft cafe to an immediate attraétion be- 
tween the fwimming body and the fide of the veflel, See 
Helfkam’s Lectures, Betore 1 had obferved the fourth 
cand fixth cafes, 1 thought the phenomena might be alk 
v 
explained from this principle, that the light bodies al- 
ways tend tothe higheft parts of the water. It has been 
fuggelted to me by fome, that this tendency, combined 
with the greater or lefler immerfion of the bodies, upon 
account of the ring of water which they elevate or de- 
_ prefs, may produce all the different cafes ; and by others, 
that the whole is explicable from the fingle principle of 
attraction between the parts of water which caufes two 
drops to run into one. I believe it will be found, on due 
confideration, that none of thefe accounts is heiduabry ‘ 
But there is no reafon to defpair of coming to the bot- 
tom of thefe p/enomena; fiace other motions of a like 
_ kind have been fuccesfully explained. Thus the running 
of a drop of oil towards the concourfe of two glafs-planes, 
and the motion of a bubble on the furface of liquors, 
when the glafs is held obliquely towards that point 
where the glafs is inclined to the liquor in the fmalleft 
"angle, are eafily underflood from the diregion of the 
_ Sompound force with which the drop and bubble are 
acted, 
