among physicians, denotes an atrophy or consumption, in its last and most deplorable stage.

**MARBLE** in natural history, a genus of foliis; being bright and beautiful stones composed of small separate concretions, moderately hard, not giving fire with steel, fermenting with and soluble in acid menstrua, and calcining in a slight fire.

The colours of marbles being a very obvious and striking character, they are arranged according to them in the following divisions. 1. Of the white plain marbles there are two sorts; the Parian marble of the ancients, and statuary marble of the moderns, an extremely bright and elegant marble; and the Carara marble, a very fine marble, more compact and close than the former, but less bright. 2. Of the plain yellow with marbles there is only one sort, which is a hard, pale yellow, and glossy marble, found in many parts of Italy. 3. Of the bluish and black marbles there are a great many species, as the Chian marble, basaltes, &c. 4. Of the plain green marbles there is only one kind the Lacedemonian marble of the ancients. 5. The pale coloured or whitish brown, commonly called Darby-marble. 6. The green marbles with shells 7. The black coralloide marble, with and without shells. 8. Of the white variegated marbles there are a great many species, variegated with purple, brown, red, blue, &c. 9. Of the brown variegated marbles there are likewise several sorts, some with red veins, others with white, black, or brown veins. 10. Of the yellow-veined and variegated marbles, some are veined with purple, and others with blue. 11. Of the black variegated marbles, some are veined with white, and others with blue, yellow, red, &c. 12. The green variegated marbles are likewise distinguished by the colour of their veins. 13. The gray spotted marbles are variegated, some with black, and others with green spots. 14. The red variegated marble is the brocatello of the Italians, with white and gold veins.

**Colouring of Marble**. The colouring of marbles is a nice art; and in order to succeed in it, the pieces of marble on which the experiments are tried must be well polished, and clear from the least spot or vein. The harder the marble is, the better it will bear the heat necessary in the operation; therefore alabaster, and and the common soft white marble, are very improper to perform these operations upon.

Heat is always necessary for the opening the pores of the marble, so as to render it fit to receive the colours; but it must never be made red hot; for then the texture of the marble itself is injured, and the colours are burnt, and lose their beauty. Too small a degree of heat is as bad as too great; for, in this case, though the marble receive the colour, it will not be fixed in it, nor strike deep enough. Some colours will strike, even cold; but they are never so well sunk in as when a just degree of heat is used. The proper degree is that which, without making the marble red, will make the liquor boil upon its surface. The menstruums used to strike in the colours must be varied according to the nature of the colour to be used. A lixivium made with horse's or dog's urine, with four parts quick lime, and one part pot-ashes, is excellent for some colours; common lye of wood-ashes does very well for others; for some, spirit of wine is best; and finally, for others, oily liquors, or common white wine.

The colours which have been found to succeed best with the peculiar menstruums, are these: stone blue dissolved in six times the quantity of spirit of wine, or of the urinous lixivium; and that colour which the painters call firmous, dissolved in common lye of wood-ashes. An extract of saffron, and that colour made of wort-horn-berrries, and called by the painters sap-green, both succeed well dissolved in urine and quicklime, and tolerably well in spirit of wine. Vermilion, and a fine powder of cochineal, succeed also very well in the same liquors. Dragon's blood succeeds very well in spirit of wine, as does also a tincture of logwood in the same spirits. Alkanet root gives a fine colour, but the only menstruum to be used for this is oil of turpentine; for neither spirit of wine, nor any lixivium, will do with it. There is another kind of sanguis draconis, called dragon's blood in tears, which, mixed with urine alone, gives a very elegant colour. Besides these mixtures of colours and menstruums, there are some colours which are to be laid on dry and unmixed. These are dragon's blood, of the purest kind, for a red; gamboge for a yellow; green wax for a green; common brimstone, pitch, and turpentine, for a brown colour. The marble, for these experiments, must be made considerably hot, and then the colours are to be rubbed on dry in the lump. Some of these colours, when once given, remain immutable; others are easily changed or destroyed. Thus the red colour given by dragon's blood, or by a decoction of logwood, will be wholly taken away by oil of tar-tar, and the polish of the marble not hurt by it.

A fine gold colour is given in the following manner: take crude sal ammoniac, vitriol, and verdigris, of each equal quantities; white vitriol succeeds best; and all must be thoroughly mixed in fine powder.

The staining of marble to all the degrees of red or yellow, by solutions of dragon's blood or gamboge, may be done by reducing these gums to powder, and grinding them, with the spirit of wine, in a glass mortar; but for smaller attempts, no method is so good, as the mixing a little of either of these powders with spirit of wine in a silver spoon, and holding it over burning charcoal. By this means a fine tincture will be extracted; and with a pencil dipped in this, the finest traces may be made on the marble while cold, which, on the heating it afterwards either on sand, or in a baker's oven, will all sink very deep, and remain perfectly distinct in the stone. It is very easy to make the ground colour of the marble red or yellow by this means, and leave white veins in it. This is to be done by covering the places where the whiteness is to remain with some white paint, or even with two or three doubles only of paper, either of which will prevent the colour from penetrating in that part. All the degrees of red are to be given to marble by means of this gum alone; a slight tincture of it, without the affluence of heat to the marble, gives only a pale flesh colour, but the stronger tinctures give it yet deeper; to this the affluence of heat adds yet greatly; and finally, the addition of a little pitch to the tincture gives it a tendency to blackness, or any degree of deep red that is desired. A blue colour may be given also to marble by dissolving turnfol in a lixivium of lime and urine, or in the volatile spirit of urine; but this has always a tendency to purple, whether made by the one or the other of these ways. A better blue, and used in an easier manner, is furnished by the Canary turnfol, a substance well known among the dyers; this needs only to be dissolved in water, and drawn on the place with a pencil: this penetrates very deep into the marble, and the colour may be increased by drawing the pencil wetted afresh several times over the same lines. This colour is subject to spread and diffuse itself irregularly; but it may be kept in regular bounds, by circumscribing its lines with beds of wax, or any other such substance.

Polishing of Marbles is performed by first rubbing them well with a free-stone, or sand till the strokes of the axe are worn off, then with pumice stone, and afterwards with emery.

Arundel-Marbles, ancient marbles with a chronicle of the city of Athens inscribed on them, many years before our Saviour's birth; presented to the university of Oxford by Thomas earl of Arundel, whence the name.