down a few inches on to the rim of the wheel, and there remain.

The body of this cart is somewhat lower, consequently. easier to load; and the line of traction being inclined, and in the most favourable direction, it will be drawn with less power than a cart with high wheels and the draught horizontal.

A cart on this construction will be two-thirds, or perhaps little more than half, the weight of the lightest kind used in this town, and the expense of building will be nearly the same. The Patentee engages that it shall be of sufficient strength to carry any load the law allows on six inch wheels, and drawn by two horses.

Waggons being rarely used either in this town or neighbourhood, it is scarcely necessary to give a particular description of their construction, but they will possess precisely the same relative advantages as a cart.

The invention is equally applicable to light carriages with narrow wheels, as coaches, chariots, &c. although. the difference in draught will not be so sensible as in broad wheels. The figure of a stage coach, (Plate XV.) is chosen as an example. It is calculated to carry the full complement of six inside and twelve outside passengers, a sufficient quantity of luggage, without placing any thing whatever on the roof, or any person (except one on the box with the driver) sitting higher than those inside. This coach is represented with low hind wheels, which will be found a great convenience (and in the author's opinion no disadvantage) in all four wheel carriages; but if it is preferred, the hind wheels may be made the usual height, without any very material deviation from the plan.

It is evident that a coach so constructed is much safer

than those in common use; first, by the loading being carried so low; next, that it runs upon a somewhat

broader

broader base, without requiring more room upon the road; and, thirdly, having no perch, it cannot be overset by turning too short; the horses heads may be brought round to the hind wheels, and the carriage will go round after them in the smallest space possible. The usual base occupied by the hind wheels of a stage coach is four feet ten inches upon the road, and they diverge to the extent of six feet two inches. This coach runs upon five feet exactly, and the extreme breadth of the frame is five feet ten inches. But for further particulars, the author must refer to the description of his invention, and observations on wheel carriages in general, lately published by J. Taylor, High Holborn, and sold by Robinson and Sons, and the other booksellers in Liverpool.

In that little work it is mentioned, that the whole body of a stage coach had been placed upon a carriage of this construction, which was partially altered to carry the hind passengers something lower, and for the performance of this very imperfect machine, the testimonial below of Mr. Thomas Blacklock, who has driven it the most frequently, is referred to; as is also to that of Mr. Varty, the builder.

The outline engraving, No. 3, (Plate XV.) is a stage coach as proposed, shewing a well for luggage under the body: the half plan is described under the elevations.

Mr. Koster has appointed Mr. Jonathan Varty his agent in Liverpool for the construction of all kinds of coaches, chariots, chaises, &c. on the principle of his Patent: and he has undertaken, for the present, the inspection of a manufactory of carts and waggons in Great Charlottee-street.

AT the request of Mr. Koster, the inventor of an improvement in building wheel carriages, I hereby declare,

that

that having driven an old stage coach placed upon a carriage on his plan, the springs outside the wheels, &c. between this town and Ormskirk, for nearly four months, I have always found that it is drawn with less fatigue to the horses than other coaches; and, according to the best of my judgment, it runs lighter, with the full complement of eighteen passengers and luggage, than any other coach I have driven with twelve passengers: it has likewise been generally much approved by the passengers for its greater safety. Liverpool, Feb. 1819.

THOMAS BLACKLOCK.

I hereby declare, that the stage coach specified by the driver, T. Blacklock, was, as far as practicable, altered to Mr. Koster's plan, at my manufactory in this town; and I am of opinion, that if a coach were built entirely new upon this principle, it would be found to possess every advantage ascribed to it by the inventor.

Hunter-street, Feb. 15, 1819.

JONATHAN VARTY.

The cart that was first built for the purpose of making experiments has been not only fairly, but, it may be said, severely tried, having been employed for nearly three weeks in carrying heavy loads about the distance of three-fourths of a mile, seven or eight times a day: the loads have weighed from 15 to 25 cwt. each; the driver is confident some of them exceeded one ton and a half, and drawn by one old stage coach horse with apparent ease. The wheels have so far preserved their vertical position and parallelism to each other without the smallest deviation; they are four feet high, and the axle-tree two inches and a quarter diameter.

New

New Experiments on some of the Combinations of Phosphorus. By Sir HUMPHRY DAVY, LL. D. F. R.S. V.P.R.I.

With an Engraving.

From the PHILOSOPHICAL TRANSACTIONS of the ROYAL SOCIETY of LONDON.

(Concluded from Page 296.)

IN examining minutely the circumstances of the action

of the liquid chloride, or solutions containing phosphorus and muriatic acids, or nitrate of silver, I found no difficulty in explaining the cause of the error in the former experiments. Phosphorus acid acts upon nitrate of silver, and more rapidly in proportion to its concentration, and gradually produces a copious precipitate from it; so that if there be an excess of nitrate of silver, and the precipitate be not immediately separated from the solution, there is always a considerable increase of weight. M. Dulong, and M. Berzelius, whose experiments agree with my former ones, may have been misled by a precipitation from the nitrate of silver by phosphorus acid, as I am sure I was. M. Berzelius does not state how he prepared his liquid chloride of phosphorus; but M. Dulong, who objects to my process by corrosive sublimate, and employs, instead of it, the action of chlorine on phosphorus in forming his fluid, must have been exposed to other sources of error. He speaks of acting on dry phosphorus by dry chlorine; but it must be always extremely difficult to free a gas that cannot be kept over mercury, of all its vapour; and as perchloride always forms during the action of phosphorus on chlorine, a part of which produces a fluid, and easily volatile hydrate with water, and soluble in all proportions in the liquid chlo

ride, this process must be very liable to error. I have never been able to form the perchloride, even from chlorine slowly passed through muriate of lime, without producing a small quantity of liquid hydrate of perchloride, which, when the solid perchloride was converted into liquid by more phosphorus, rose in vapour with it, and which, containing nearly a double quantity of chlorine, (for the water forms a very small part of it) occasions the precipitation of a much larger quantity of horn silver than the pure chloride formed from corrosive sublimate.

These various experiments on the combination of phosphorus with oxygen and chlorine, sufficiently agree with each other to afford the means of determining the proportion in which phosphorus combines with other bodies, or its equivalent number considered as an element.

If the absorption of oxygen be considered as offering the data, and phosphoric acid be supposed to consist of two proportions of oxygen, and one of phosphorus, the number representing the proportion in which phosphorus combines, will be 22.3. If phosphoric acid be considered as consisting of four proportions of oxygen, the proportional number or equivalent of phosphorus will be 44.6.

If the absorption of chlorine in forming phosphorane be made the datum, the number will be the same, 22.2, or the double 44.4. If the quantity of horn silver formed from the liquid chloride, taking the mean of all the experiments, be assumed as the datum, the number would be 23.5, or the double 47: the mean of all these proportions is 22.6, or the double 45.2; or taking away decimals, 45.

In referring to the analyses which have been made of the different combinations of phosphoric acid, for the purpose of ascertaining if they correspond with this number, I found the data so uncertain and so discordant,

that