and applied to a proper flame: but it appears that the means which have hitherto been employed to accomplish these ends, are, more or less, defective.

"The most general method, is that of supplying this instrument with the breath. In addition to the well known difficulty of keeping up a constant emission of air during respiration, and its injurious effect upon the lungs*, it may be remarked, that as the breath is loaded with moisture, and partially carbonized, it is proportionably unfit for combustion; and the impossibility of supporting a flame with oxygen gas, by this method, is obvious.

"Another way of supplying the blow-pipe with air, is that of connecting with it a small pair of double bellows. A contrivance of this kind possesses obvious advantages over the mouth blow-pipe; but, owing to the pervious nature of the materials of which bellows are constructed, and the difficulty of making their valves air-tight, the greater part of the air drawn into them escapes at other places than the proper aperture. A pair of bellows, of this kind, belonging to an artist of this city, which were not considered as less air-tight than usual, were found to discharge the complement of their upper compartment, in six-sevenths of the time, when the orifice of the pipe was open, which was requisite when it was closed. Hence, it appears that six-sevenths of the air ejected into the upper compartment, escaped at other places than the proper aperture; and if to this loss were added that sustained by the lower compartment, the waste would be much greater. As, in operating with these machines, in is necessary constantly to move the foot, the operator cannot leave his seat; and, in nice operations, the motion of his body is an inconvenience, if not a source of failure. Bellows of this kind cannot be used for supplying combustion with oxygen gas; because, as this air is only to be obtained by a chemical process, it is very desirable to avoid any waste of

* In consequence of this, some artists have abandoned the use of the in

strument.

it; and, as there is always a portion of air remaining in them, even when the boards are pressed as near to each other as the folding of the leather will permit, any small quantity of oxygen gas which might be drawn into them, would be contaminated.

"Being sensible of the advantage which would result from the invention of a more perfect method of supplying the blow-pipe with oxygen gas or atmospheric air, I was induced to search for means of accomplishing this object. The result of my attention to the subject, is the production of a machine, of which there follows an engraving and description."

The machine, which the figure represents*, does not differ essentially from that alluded to, in the passage above quoted. The construction is, however, more simple and easy.

Explanation of the Figure.

The hydrostatic blow-pipe, consists of a cask, divided by a horizontal diaphragm, into two apartments, DD. From the upper apartment, a pipe of about three inches in diameter, its axis coincident with that of the cask, descends, until within about six inches of the bottom. On this is fastened by screws, a hollow cylinder of wood, BB, externally twelve inches, internally eight inches, in diameter. Around the rim of this cylinder, a piece of leather is nailed, so as to be air-tight. On one side, a small groove is made in the upper surface of the block, so that a lateral passage may be left under the leather when nailed on each side of the groove. This lateral passage, communicates with a hole bored vertically into the wood, by a centre-bit; and a small strip of the leather, being extended so as to cover this hole, is made, with the addition of some disks of metal, to constitute a valve, opening upwards. In the the bottom of the cask, there is another valve, opening upwards. A piston rod, passing perpendicularly through * See plate I. fig. 1.

the pipe, from the handle, H, is fastened near its lower end, to a hemispherical mass of lead L. The portion of the rod beyond this proceeds through the centre of the leather, which covers the cavity formed by the hollow cylinder; also through another mass of lead, like the first, which being forced up by a screw and nut, subjects the leather, between it and the upper leaden hemisphere, to a pressure sufficient to render the juncture air-tight. From the partition, an eduction pipe is carried under the table, where it is fastened, by means of a screw, to a cock which carries a blow-pipe, so attached, by a small swivel joint, as to be adjusted into any direction which can be necessary. A suction pipe passes from the opening covered by the lower valve, under the bottom of the cask, and rises vertically, close to it, on the outside-terminating in a staple, with a screw in it, g, for the attachment of any flexible tube which may be necessary.

The apparatus being thus arranged, and the cask supplied with water, until the partition is covered, to the depth of about two inches, if the piston be lifted, the leather will be bulged up, and will remove, in some degree, the atmospheric pressure from the cavity beneath it; consequently, the air must enter through the lower valve, to restore the equilibrium. When the piston is depressed, the leather being bulged in the opposite direction, the cavity beneath it is diminished, and the air, being compressed, forces its way through the lateral valve into the lower apartment of the cask. This apartment being previously full of water, a portion of this fluid is pressed up, through the pipe, into the upper apartment. The same result ensues every time that the stroke is repeated; so that the lower apartment soon becomes replete with air, which is retained by the cock, until its discharge by the blow-pipe is requisite.

The cock being opened, the air confined in the lower apartment, is expelled by the pressure of the water in the upper apartment, which, as the air which had displaced it

escapes, descends and re-occupies its former situation. The piston is worked either by the handle, or the treadle,

at C.

In order to supply the cask with oxygen gas, it is only necessary to attach to the suction pipe, by means of the staple and screw at g, another pipe, duly flexible, and passed under a bell containing the gas in question, over the pneumatic cistern. Or the pipe may communicate with a leather bag, filled with oxygen. I have one, which will hold fifty gallons; the seams are closed by rivets, agreeably to Pennock and Sellers' plan for mail bags, or fire-hose.

Having used the hydrostatic blow-pipe for five and twenty years, I am enabled to speak in favour of its conveniency, with the confidence due to this long trial. I am persuaded, that it would be found exceedingly useful, to all artists who employ the blow-pipe in soldering, or in blowing or moulding the tubes of thermometers, barometers and other processes, to which the enamellers' lamp is applied.

Associated with the large self-regulating reservoir of hydrogen, to be described in the next number of this work, it is, with the aid of a jet of atmospheric air, supplied to it in the compound blow-pipe, competent to fuse platina; and the facility with which the hydro-oxygen flame thus produced, may be made to act in any convenient direction, would render it highly serviceable to silversmiths, coppersmiths, and pewterers. In soft soldering, it is often far more efficacious than a soldering iron. Its peculiar cleanliness is worthy of attention; in this respect it greatly excels the ordinary blow-pipe flame. Besides, the limits are peculiarly ample, within which it is susceptible of an instantaneous increase or diminution in size or intensity.

I do not believe the heat produced in this way, to be much more expensive than that produced by a lamp.

(To be continued.)

II.-On the advantages of steaming Potatoes, &c., as Food for Horses and other Cattle. By JOHN CHRISTIAN CURWEN, Esq. M. P.

WITH A FIGURE.

(Continued from Vol. IX. page 342.)

MY DEAR SIR, Workington Hall, Nov. 15, 1811. YOUR letter roused me into action; I cannot suffer you to suppose I can slacken in my exertions. Though great and important improvements have been made in agriculture in the last few years, it is far distant from perfection even in the most improved districts. The comfort and happiness of the many has always held out to me the strongest incentive for exertion, and no part of my farming operations have yielded me equal gratifications as my dairy.

The result of what was done at the Schoose last year has confirmed my opinion that a plentiful supply of good and unadulterated milk is of the highest importance to the comfort and health of the lower orders; 145,000 quarts of new milk were sold in the last twelve months. Milk is now become a necessary of life. Five years ago the amount of the total sale to the town of Workington, containing between eight and nine thousand souls, might be £1,500 per annum, or at two pence per quart, wine measure, 108,000 quarts. From the best information I can obtain, I conceive I am warranted in stating the present sale of milk to be above £5,000 per annum, or 600,000 quarts. Thus the proportion to each individual in the year 1806, would be 20 quarts, in the year 1811, 60 quarts. The truth is, that it was but in partial use. Now, sir, I believe I may assume, that what was the situation of Workington a few years ago, is that of the greater part of the kingdom at present. That species of human food which is produced in the greatest abundance with the least consumption of the fruits of the earth, is a luxury, and not as it ought to be, one of the staple articles of consumption. Impressed with these sentiments, you will not wonder if I