principle. The decanted liquid had a slight smell of sulphureous acid which went off on exposure to the air. If the petroleum still retains after this process its bituminous smell, it shews that it has not been sufficiently shaken with the acid, and it must be repeated with a fresh dose of acid.

The petroleum was then mixed with a solution of one part of dry caustic potash in twenty parts of water. The petroleum was then drawn off and put by itself into an empty bottle of ten times its capacity, and shaken violently; four or five parts of water were then added which formed a milky liquid, a compound of acid and petroleum with water, over which swam the rest of the petroleum almost pure. This latter oil was again shaken in the empty bottle, and then with water, till I obtained a petroleum with even less scent than any fixed vegetable oil, and retaining only a very slight quantity of sulphuric acid. This oil was at first muddy, but it became quite clear by filtration through paper and rest for a few hours.

The time and labour of the successive shakings of the oil, first by itself and then with water, may be much abridged by using a stronger solution of potash in the first instance; but the advantage of this might be counterbalanced by the cost of the alkali. The proportion of alkali which I have given, is much more than is necessary to saturate the acid which adheres to the oil, so that the same alkali may serve several times if extracted from the residue by calcination in a red heat.

In a note to this paper, the editor of the Annales de Chimie, suggests that the coarse petroleum may be purified in much less time if it is previously distilled with water, which would separate the essential oil of the petroleum from the bituminous matter with which it is naturally combined.

URBANUS

List of Patents for Inventions, &c.`.

(Continued from Page 192.)

RBANUS SARTORIS, of Winchester-street, London, Merchant; for improvements in the construction and use of fire-arms. Dated January 23, 1819.

JOSEPH HILL, of Paulton, Somersetshire, Gentleman; for a machine or top for the cure of smoky chimnies. Dated January 23, 1819.

JAMES FOX the younger, of Plymouth, Devonshire, Rectifier; for a method or methods of diminishing the loss, in quantity and quality, of ardent spirits, and other fluids, during the process of distillation or rectification. Dated January 28, 1819.

MATTHEW THOMAS, of Greenhill's-rents, Middlesex, Engineer; for a plough, upon which he hath invented an ́improvement, and also a propelling power applicable to ploughs in general, also to various other implements and machines. Communicated to him by a foreigner residing abroad. Dated January 35, 1819.

HENRY EW BANK, of London, Merchant; for machinery for cleaning or dressing paddy or rough rice, so as to fit it for culinary purposes, which he conceives will be of great public utility. Dated February 9, 1819.

JAMES SIMPSON, of the city of Edinburgh, Esq.; for a method or methods calculated to convey gas used for illumination to the burners, and at the same time suspend the burners, or the lamps, lustres, or other frames or holders, in which the burners are placed. Dated February 9, 1819.

ROBERT WILLIS, of Upper Norton-street, St. Maryle-bone, Middlesex, Gentleman; for an improvement or improvements upon the pedal harp, which he conceives will be of public utility. Dated February 13, 1818.

Specification of the Patent granted to HENRY MATTHEWS, of Gretton Place East, Bethnal Green, in the County of Middlesex, Gentleman; for certain Improvements applicable to wheeled Carriages, or Vehicles of different Descriptions, calculated to render them more safe and commodious. Dated November 19, 1818.

With an Engraving.

To all to whom these presents shall come, &c. NOW KNOW YE, that in compliance with the said proviso, I the said Henry Matthews do hereby declare that my said invention is fully and particularly described by the drawings hereunto annexed, and the following description thereof; that is to say: The present form of stage coaches is such as to oblige a large portion of passengers and parcels to be placed on the roof, at between eight and nine feet from the ground, and the remaining outside passengers nearly as high; so that should the outside be loaded and not the inside, (which frequently happens,) it is possible that the centre of gravity may be

VOL. XXXIV.-SECOND SERIES. LI between

between seven and eight feet from the ground, and the track of the wheels only four feet eight inches apart, which, with a quick motion, and an inclining road, are sufficient to make thinking persons uneasy; for at present no adequate provision has been made to prevent accidents, should the centre of gravity pass the track of either of the wheels. If a column of fifteen feet in height, and only four feet eight inches in diameter, was to pass along at a quick rate, every one would expect to see it fall; and yet this would be exactly as safe as one of the present stage coaches, loaded as above described, the breadth of the base being the same in both, as well as the height of the centre of gravity. Passengers, both inside and out, (except those on the roof,) sit on single seats; the space under them is lost, or nearly so, being too small for stowing any thing to advantage. The inside passengers sit breathing in each other's faces, and so close as not to admit room to change the position of their legs : no one can see out of the windows without stooping forwards, and looking sideways, a painful position; at which time the other passengers are excluded from the prospect, however beautiful. The luggage on the outside is liable to pilfering, and damage from wet. The back part is frequently so constructed as to admit of two or three persons besides the passengers clinging to it.

My improvements, as applicable to stage or other coaches, consist of double seats in the centre, for inside passengers to sit nearly back to back, looking towards the side windows, so that they may see the prospect, have room for their legs, and not incommode each other. (See B B, Plate IX. in the annexed drawing.) C the space under the seats, forming the back, boot, or luggage-box. EFG, seats provided for the whole licensed number of outside passengers, at a pleasant height,

(about

靠

(about six feet six inches): these seats being broad, and two together, the space under them forms the front boot or luggage-box H. The whole of the luggage is under lock, no part of it exposed to wet or pilfering, or left to incommode the passengers. The luggage rests at I, about three feet six inches from the ground, instead of eight feet nine inches. Thus the centre of gravity is lowered between two and three feet. The axletree should be lengthened so as to make the track of the wheels about five inches wider, or further from each other than at present it will then be scarcely possible for such a coach to turn over, as the two wheels on one side may run on a bank, two feet four inches high, without losing its balance, see K. But, in order to remove all apprehension on that head, the following plan may (if desired) be added, viz. from each side of the body let an iron crutch hang pendant, the bottom of which forms a spring, reaching within about six inches of the ground L, so that if any part of the carriage should break, the body, and the part where the outside passengers are can only fall six inches, and that on a spring, which will prevent sudden concussion; and should any thing heave the coach on one side, the pendant crutch on that side strikes the ground before the body of the coach can pass the line of gravity, or go beyond its balance. Nothing is left to human agency: the crutch acts of itself, by always keeping perpendicular, see M. The crutch I consider rather as a superabundant caution, but by no means absolutely necessary. To prevent the wheels from flying off, the box may be of equal diameter at both ends, to admit of the axletree or arm being put through from the outside, see N, and fastened to the bed in the centre with screws and nuts, 00: the wheels are thus secured by solid knobs of iron, like the head of a kitchen-poker, instead