The solution being thus prepared, take up a drop of it with a goose quill, cut in fashion of a scoop, and place it on a flat slip of glass, of about three quarters of an inch in width, and between three and four inches long, spreading it on the glass with the quill, in either a round or oval figure, till it appears a quarter of an inch or more in diameter, and so shallow as to rise very little above the surface of the glass. When it is so disposed, hold it as level as you can over the clear part of a fire that is not too fierce, or over the flame of a candle, at a distance proportionable to the degree of heat it requires, which experience only can direct, and watch it very carefully till you discover the saline particles beginning to gather and look white, or of some other colour, at the extremities of the edges; then having adjusted the microscope before-hand for its reception, armed with the fourth glass, which is the fittest for most of these experiments, place it under your eye, and bring it exactly to the focus of the magnifier; and after running over the whole drop, fix your attention on that side where you observe any increase or pushing forwards of crystalline matter from the circumference towards the center. This motion is extremely slow at the beginning, unless the drop has been over-heated, but quickens as the water evaporates, and in many kinds, towards the conclusion, produces configurations with a swiftness inconceivable, composed of an infinity of parts, which are adjusted to each other with an elegance, regularity, and order, beyond what the exactest pencil in the world, guided by the ruler and compass, can ever equal, or the most luxurious imagination fancy. When action once begins, the eye cannot be taken off, even for a moment, without losing something worth observation; for the figures alter every instant, till the whole process is over; and in many sorts, after all seems at an end, new forms arise, different entirely from any that appeared before, and which probably are owing to some small quantity of salt of another kind, which the other separates from, and leaves to act after itself has done; and in some subjects three or four different sorts are observable, few or none being simple and homogeneous. When the configurations are fully formed, and all the water evaporated, most kinds of them are soon destroyed again by the moisture or action of the air upon them; their points and angles lose their sharpness, become uneven and defaced, and moulder as it were away; but some few are permanent, and by being inclosed between glasses, they may be preserved months or even years.