Salts and Saline Suhjlances. 11 
Fafhion of a Scoop, and place it on a flat Slip 
of Glafs of about three Quarters of an Inch 
in Width, and between three and four Inches 
long, fpreading it on the Glafs with the 
Quill, in either a round or oval Figure, till 
it appears a Quarter of an Inch or more in 
Diameter, and fo {hallow as to rife very 
little above the Surface of the Glafs. When 
it is fo difpofed, I hold it as level as I can 
over the clear Part of a Fire that is not too 
fierce, or over the Flame of a Candle at a 
Difiance proportionable to the Degree of 
Heat it requires, (which Experience only 
can dired,) and watch it very carefully, till 
I difcover the Saline Particles beginning to 
gather and look white, or of fome other Co¬ 
lour, at the Extremities of the Edges. Then 
(having adjufted the Microfcope beforehand 
for its Reception, armed with the fourth 
Glafs, which is the fitted for mod; of thefe 
Experiments,) I place it under my Eye, and 
bring it exadly to the Focus of the Magni¬ 
fier, and after running over the whole Drop, 
I fix my Attention on that Side where I 
obferve any Increafe or pufhing forwards of 
cryftaline Matter from the Circumference 
towards the Center. 
This Motion is extremely flow at the Be¬ 
ginning, unlefs the Drop has been overheat¬ 
ed, but quickens as the Water evaporates, 
and in many Kinds towards the Conclufion 
produces Configurations with a Swiftnefs 
uncon- 
