Both these products are of a yellowish brown colour, and require a process of bleaching to deprive them of it.

We have seen candles made from the stearin of palm oil, which were very little inferior to wax in illuminating power; they were cast in moulds, from which they readily separated by contraction when cold, in this respect possessing an advantage over wax. The odour emitted by the substance is like palm soap, and is generally considered rather agreeable than otherwise. It may, perhaps, be necessary to explain to the general reader that the palm oil of commerce, and that to which the last mentioned patent relates, is the produce of a tree growing abundantly in Africa and South America, where, as well as in other parts of the world, it is obtained from the outer shell or pulpy rind of the palm nut, while the kernel of the nut contained within the inner indurated shell is thrown away as useless in the preparation of oil or other oleaginous articles of commerce. These kernels, however, have been recently found to abound in oleaginous matter of superior quality, eminently calculated for the production of candles, besides generally for those purposes for which fluid and concrete oils are used. For the introduction and application of this valuable {refuse) matter, the public is indebted to Mr. John Demeur, who has recently taken out a patent for this interesting discovery.

The process described by the patentee in his specification is as follows: " l first subject the kernels to a slight heating in an oven, or other convenient apparatus, carrying the process only so far as to render the kernels comparatively crisp and brittle when cold, which facilitates the subsequent operation of grinding them to a paste in a mill. This paste l dilute with one-fourth of its weight of boiling water, and then put it into bags (of the usual kind employed in oil mills), wherein l subject it to mechanical pressure by the ordinary mechanism employed for similar purposes, preferring, however, to place the said bags containing the paste between heated metallic plates. By the joint action of heat and pressure so applied, the oleaginous matter in copiously exuded through the interstices of the bags, and is collected in suitable receivers to undergo a purification. This purification l usually effect by remelting the last mentioned product, and filtering it whilst in a fluid state; and if it be desired to purify or refine it still farther, or to remove the slight tinge of colour it may yet possess, l again melt it in a metallic vessel coated with tin, and mix therewith, by agitation or stirring, some very dilute sulphuric acid.

By this process the impurities are precipitated, or subside, by rest, to the bottom of the vessel, and the oleaginous matter floats above the water, whence it is removed, and subsequently consolidated, by evaporating the aqueous particles that were commixed with it in the previous operation. The product resulting from the last described process is a white and partially concrete matter, as it consists of the two distinct substances, termed elain and stearin, the former of which is fluid, and the latter solid, at our ordinary atmospheric temperature. To separate these, they are subjected again in bags to mechanical pressure, without the aid of artificial heat, if the weather be warm; but if the air be under 65°, the application of a slight degree of heat will assist the operation, and cause a fine fluid oil to be expressed, leaving the stearin in the bags of a similar consistence to wax or spermaceti, and from which candles, scarcely inferior to those fabricated of the last mentioned substances, and very superior to those of tallow, are made.

Having noticed the several important materials that have been introduced into the modern manufacture of candles, we shall proceed to describe some very recent and ingenious improvements in their construction and composition, which have been the subject of patents.

Dr. Bulkeley, of Richmond, in Surrey, took out a patent, dated January 26, 1830, for a plan of making tallow candles with an exterior casing of wax, and also for effecting a saving in the material used for wicks, as well as to obviate the necessity of snuffing. He uses a metallic mould, of the description generally employed in the manufacture of mould candles, and fills it with melted wax. Now, as the portion of the wax which is in contact with the interior surface of the mould will become, by the conducting powers of the metal, first cooled or set, as it is termed, the wax remaining fluid in the centre of the mould is poured off, leaving within the mould a hollow cylinder of wax, which is afterwards filled with tallow, or any other material which melts at a lower temperature than wax. With respect to the wick, the patentee introduces a small thread up the centre of the candle, for the purpose of constituting a guide for a short cotton wick, which is plaited with a piece of straw within it, to receive the thread.

This short wick rests on the surface of the tallow, which it raises by its capillary attraction for the supply of the combustion; and as it descends upon the thread as the tallow is melted, the top of it is never removed so far from the tallow as to carbonize and require snuffing, which is the case with wicks of the ordinary construction. The ordinary mode of manufacturing wax candles, described in the early part of this article, has, we understand, been resorted to, on account of the presumed difficulty of removing them from the moulds, to which they firmly adhere, if cast therein. To obviate this difficulty, Dr. Bulkeley places a block of box-wood, having a cavity in it to receive the lower ends of the candle, in contact with the annular edge of the mould; then striking the block a few smart blows with a mallet, he detaches the candles from the moulds.

A patent was also granted on the 4th February, 1830, to Mr. Charles T. Miller, of Piccadilly, Westminster, for certain improvements in making candles. These consist in the use of a small glass ring, which is placed over the wick, and descends as the candle burns. The object in view is to prevent the candle from wasting or guttering, which it effects by the glass ring conducting a greater quantity of heat to the centre of the candle than that which reaches the exterior; so that candles provided with this ring burn hollower in the centre than others, and the exterior tallow, or composition of which the candles are made, stands higher, and descends to the wick as soon as it is melted. The method of manufacturing the candles with the glas3 rings, as described by the patentee, consists in putting the ring over the wick after it has been placed in the centre of the mould, which, being inverted, as it is while being filled with the oleaginous matter, the ring descends until it reaches that part of the conical extremity of the mould which is equal in diameter to the exterior of the ring, when it rests, and becomes fixed in the candle.