be no affinity. Thus, there is no affinity between water and oil; and there is a greater affinity between water and spirit of wine than between water and common salt; inasmuch as a combination of the two latter ingredients is destroyed, if the water be permitted to combine with spirit of wine; in which case the salt sinks to the bottom, and the water is no longer saline to the taste.

Chemists once flattered themselves with the hope of a richer reward than commonly belongs to the labours of science. They believed that they should be able to make gold. It had been customary to consider all bodies as composed of certain permanent and unchangeable parts, called elements; and the end of chemistry as the power of resolving bodies into these elements, and recomposing them again by a proper mixture of the elements when so separated. Upon this supposition the alchemists went; who, conceiving that all bodies were composed of salt, sulphur, and mercury, endeavoured to find out the proportions in which they existed in gold, and then to form that metal by combining them in a similar manner. Had they taken care to ascertain the real existence of these elements, and, by mixing them together, composed any one metal whatever, though but a grain of lead, their pretensions would have been rational and well founded; but as they never did this, their want of success is not surprising.

CHEMICAL apparatus: the object of chemistry being to ascertain the ingredients of which substances are composed, to examine the nature of those ingredients, and the properties resulting from their combination or union, it is necessary that

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there should be divers instruments for the purpose. For the mechanical division of bodies it is requi site the chemist should have hammers, knives, files, and rasps, for breaking, cutting, rasping, filing and shaving he should have mortars for pounding; a stone and muller for levigating: a pair of rollers for laminating metals, a forge for many of the purposes in which the blast-heat of a small fire is required; LAMPS, FURNACES, &c. descriptions of which will be found under the proper heads. We shall in this article describe some of the familiar apparatus necessary to a young chemist, and to which we shall have occasion to refer in other parts of our work. The very first thing to be got is the apparatus for obtaining gases. Plate I, Chemistry, fig. 1. is a tub or trough A Z full of water, with a shelf, K K K, in it. B, G, F are glass jars or receivers, inverted with their mouths downwards. We shall point out its use by the example of Oxygen gas. C is a glass bottle into which are put some red-lead or manganese, and a small quantity of dilute sulphuric acid. D is a glass tube generally fitted by grinding to the neck of the bottle, and curved so as to enter conveniently below the shelf and communicating with one of the jars or receivers B, G, F. E is a glass retort, such as is shewn figure 5, which may be applied to the same purpose. If the bottom of the bottle C be heated by means of a wax taper or common candle, the oxygen gas will rise in bubbles, and fill the receiver, from which it drives out the water.

Fig. 2. Represents an elegant chemical apparatus of the same nature, used by Mr. Davy, the professor of chemistry, at the Royal Institution,

A, is a japanned tin vessel, filled within two or three inches of the top with water. Just below the surface of the water is fixed a shelf, having several holes bored through it, to which smallfunnels are attached underneath. The glass receiver B, intended to receive the gas, is filled with water, and being inverted with its month under water, it is raised up gently, and placed upon the shelf over one of the holes, where it will remain full of water, which is kept up by the pressure of the atmosphere, in the same way as the mercury is retained in the tube of a barometer.

The materials from which the gas is to be disengaged, are put into the retort G, which is put through and suspended in one of the rings of the lamp furnace. A E is an improved Argand's lamp, having two concentric wicks, placed on a shelf which is moveable up and down to bring the lamp to a convenient distance from the retort. The lamp is to be lighted, and as soon as the substances in the retort act upon each other, the gas will begin to be disengaged, and will ascend through the whole of the shelf into the vessel B, and displace or force down the water with which it had been filled. When the water is displaced, the receiver is full of gas, which may be preserved in it, by keeping its mouth always under water in the cistern.

The gas so obtained may be transferred from the vessel B, to any other, in the following manner: fill the vessel into which the gas is to be transferred, with the fluid in the trough, and place it on the shelf, over one of the holes. Then take the vessel B, and keeping its mouth still under the

troducing the materials through, it is called a tubulated retort. B is the receiver for condensing the vapour which is raised, and into which the neck of the retort is inserted. The joining b, is made air-tight by some substance, such as paste, applied to it, called in chemistry luting.

When great heat is employed, earthen retorts are used, and they are placed on a fire. When a less heat is wanted, glass retorts are used, which are suspended over a lamp. The receiver B is placed on some stand, which will keep it steady.

Fig. 4. A, is a chemical vessel, called a mattrass, used for distillation also, having a vessel B called an alembic, fitted to the head. The liquid, raised by heat into the state of vapour, is condensed in the alembic, and falls into a groove all round its inside, whence it runs out by the spout C into the receiver D.

Fig. 5. Is a phial with a bent glass tube, fitted into it for disengaging gases in the pneumatic apparatus.

Fig. 6. Plate II. Chemical Apparatus, is an apparatus contrived to collect such gas as cannot be received over water. The box contains mercury, and is used in every respect like the apparatus fig. 1.

Fig. 7. Exhibits the method of sublimation. Put some pieces of sulphur into the vessel A to which the receiver B is fitted and accurately luted round. A is put on a vessel filled with sand called a sand bath, which is to be heated by the furnace C. The sulphur melts, a thick white smoke arises, which is deposited in B in the form of powder. Hence it is called flowers of sulphur. The earthy