By SAMUEL PARKES, F.L.S. M.R.I. F.S.A. Ed.

Member of the Royal Asiatic Society of Great Britain and Ireland,
Fellow of the Geological and Astronomical Societies of London,
And of the Wernerian, Horticultural and Highland Societies of Scotland;
Member of the American Philosophical Society, and
Master of Arts of Yale College, Connecticut;

Member of the Imperial Natural History Society of Moscow,
The Academy of Sciences, Arts and Belles Lettre at Dijon,
And the Academy of Medicine at Marseilles;

Honorary Member of the Royal Geological Society of Cornwall,
The Antiquarian Society of Newcastle upon Tyne,

The Agricultural Societies of Philadelphia and Massachusetts, and
The Society for the Promotion of National Industry and the Arts at Lisbon;
Corresponding Member of

The Literary and Philosophical Society of Manchester; the Academy
of Natural Sciences in Philadelphia; the Philomathique
Society of Paris; and the Imperial Agricultural, and Physico-Medical
Societies of Moscow, &c.

AUTHOR OF

THE CHEMICAL CATECHISM, THE RUDIMENTS OF CHEMISTRY,

&c. &c.

THE SECOND EDITION,

Greatly enlarged, and illustrated with twenty-four Plates of Machinery
and Chemical Apparatus.

VOL. II.

London:

PRINTED FOR THE AUTHOR;

AND PUBLISHED BY BALDWIN, CRADOCK, AND JOY,
PATERNOSTER-ROW.

iii

Fig. 1 represents a section of a charcoal cylinder when fixed within the furnace. It is cut lengthwise through the middle, to show the internal work.

Fig. 2 is a contrary section of the same cylinder, the end, or front wall being in this case taken away to show how the fire plays round it before it passes off by the chimney.

Fig. 3 is an elevation of the building which incloses a cylinder when properly fixed, together with the fire-place, the tubes to carry off the acid and gas, the wine casks to receive pyroligneous acid, &c. complete.

Fig. 4. The outer shutter, to contain the stopping or luting which makes the cylinder air-tight during the operation of distilling the acid and charring the wood.

Fig. 5. The inner shutter, or stopper to prevent the stopping from getting among the charcoal.

PLATE XVI.

This drawing is the representation of a reverberatory furnace for preparing alkalies. The peculiar advantage of this furnace in preference to the one described in Plate XVII. consists in the arch by which it is covered. It will be observed that this arch springs from the ground, instead of from the floor of the oven which is usual; and this has the effect of binding the brickwork together much better than it can be done by bands of iron or by any other expedient. When the abutments are good, and

the arch properly loaded, such a furnace will endure much longer than any of those on the usual construction. The whole is drawn to a scale of of an inch to a foot, and the separate parts may be thus described:

A is the door by which the oven is charged.

BB the bridge which divides the oven from the fire-place. It is of a considerable thickness, and measures 9 inches from the top to the floor of the oven.

CC the ash-pit.

D an iron damper for regulating the draught of the fire-place. E is the passage from the oven to the chimney.

G is the floor of the oven, which should be paved with the best fire-bricks set on edge, or covered with a thick plate of iron. The latter mode is the best, when it is intended to be employed for decomposing the sulphates of soda or potash.

H is the fire-place closed by an iron hopper as described at page 158, vol. i."

I the fire bars of the same construction as those mentioned in describing Plate XVII.

KKK the main arch which covers the whole of the furnace. The part below the floor of the oven may be built with good stock-bricks; but those parts which are within reach of the fire must be composed of the best fire-bricks.

L is a line upon the brick-work of the elevation, which has been engraved to show the altitude of the oven-floor.

PLATE XVII.

The elevation and plan of a reverberatory furnace on an improved construction. The separate parts may be thus described:

A is the door by which the oven is charged, the size of which may with convenience be 9 inches by 12 inches.

BBB are three strong iron bands which go on each side of the furnace. These are fastened together by cross bars of iron which go through the brick-work of the furnace, and over the top of it, and are bound tight against the walls by screws and bars, as shown in the engraving.

C the ash-pit.

D an iron damper which runs within a groove in the brickwork of the chimney, to regulate the draught or entirely stop it at pleasure.

E the passage from the oven to the chimney.

F is a faint line on the wall of the elevation to show how the arch of the roof lessens in height as it approaches the chimney. This is designed for throwing the flame more down upon the