nated more or less with the taste and the purgative quality of the seeds: of the oil of the grana tiglia (croton tiglium of Linnæus.) Geoffroy limits the dose to one grain, which is probably an error of the press for one dram. That of the Barbadoes nut is said to be taken in America in large quantities, and to purge without much inconvenience."-Lewis's Materia Medica, vol. ii. page 272. Edit. 1791.

It appears that Geoffroy was right in the dose. Surely after the lapse of time, during which this medicine has been in the materia medica, it is neither necessary nor proper that any one should come forward, on its re-introduction, with the right and pretensions of a patent. Geoffroy was a Parisian physician, and died in 1731.

To CHARLES YARDLEY, of Camberwell, Surrey, for a new Method of manufacturing Glue from Bones, by means of Steam.

THE method proposed in this patent for obtaining gelatine from bones, is, by the employment of steam at a high pressure, which is conveyed into a closed globular vessel, containing a quantity of bones, by the action of the steam on which the gelatine is extracted, which is afterwards clarified, evaporated, and dried upon nets in the ordinary manner, so as to become the glue of com

merce.

Plate XII. fig. 1, represents that part of the apparatus which is the subject of the present patent: a, is a section of the globular vessel, or extractor, made of cast or wrought iron, or copper, but of considerable substance and strength; which is suspended upon poles, b and c,

THE NEW YORK PUBLIC LIBRARY

ASTOR, LENOX AND TILDEN FOUNDATIONS

Yardley's, for manufacturing Glue

237

and thereby enabled to revolve. b, one of the poles, is made hollow, through which the steam passes, by a pipe, from the boiler. d, is the cock, by which steam from the boiler is admitted to the extractor; the pipe through which it passes being properly provided with regulating and safety valves. e, e, is a bent tube which conducts the steam from the pipe, b, down below a grating or perforated bottom, f, ƒ, at the lower part of the globular extractor. g, is a stuffing box, by which the revolving pole, b, is coupled to the stationary steam-pipe.

A quantity of bones being collected, they are to be immersed in a pit, similar to a tan pit, filled with fresh water, and there allowed to remain for about twelve hours; the water is then to be drawn off, and the pit again filled with fresh water, which may be repeated several times, until the bones are perfectly free from dirt. After this, a solution of lime is prepared, about one bushel to five hundred gallons of water, which is to be poured into the pit, and the bones allowed to remain therein for the space of about three days. The lime water may be then drawn off, and the bones, being well washed with clean water, are ready for use.

The clarified bones are now introduced into the extractor, through the eliptical man-hole, h; and when the vessel is filled, the cover of the man-hole is slipped in, and made fast by a screw-nut, which draws it up tight against the inner surface of the globular extractor, and the edges luted, so as to be perfectly air-tight.

The steam in the boiler, having been sufficiently raised, is now to be admitted, by the cock, d, into the extractor, at a pressure equal to about fifteen pounds upon the square inch: previously, however, to the steam being admitted, the air-cock, i, must be opened, in order to allow the steam to blow through; but it must be closed as

soon as the air is expelled. The steam now passing through the tube, e, is conducted to the lower part of the extractor, and thence rising through the grating, or perforated bottom, f, insinuates itself among the bones in the vessel, a, above.

The bones having remained about an hour under the operation of the steam, a quantity of condensed liquid will have collected in the bottom of the extractor, which, when the steam is shut off, and the air-cock opened, may be drawn from the vessel by the cock, k, into a tube or other convenient receptacle. As soon as the condensed liquor is discharged, the steam is to be again introduced into the extractor, as before, there to operate for another hour upon the same mass of bones, when a second portion of condensed liquor will be obtained, which must be drawn off, as above.

The gelatinous matter having settled, and become cool, the grease which has risen upon its surface must be carefully skimmed off, when the two portions of the liquid are to be returned into the extractor, by means of a funnel introduced at the air-cock, i. The steam is now to be again introduced, and allowed to operate upon the extract of the bones for about an hour, in the course of which time the globular extractor is made to revolve slowly four or five times, by means of the winch, pinion, and toothed wheel, connected to the pole, c, and turned by manual labour. After this, the liquor is again drawn off, as before, and conducted into evaporating vessels, where the gelatinous matter is heated by steam pipes, until it has arrived at a proper consistence to form glue. This gelatinous matter, having been clarified with alum, is now discharged from the evaporating vessels into backs, or coolers; and, having settled and cooled,