this substance with greater energy than any other known bodies. Hence the minute theory of oxydation of the basis of the alkalies in the air is this:-oxygen gas is first attracted by them, and alkali formed; this alkali speedily absorbs water; this water is again decomposed; therefore, during the conversion of a globule into alkaline solution, there is a constant and rapid disengagement of small quantities of gas. From the facts related, of which we mention only a part, it is inferred by Mr. Davy, that there is the same evidence for the decomposition of potash and soda into oxygen and two peculiar substances, as there is for the decompositions of sulphuric and phosphoric acids and the metallic oxydes into oxygen and their respective bases. In the analyses, no substances capable of decomposition are present, but the alkalies and a minute portion of moisture; which seems in no other way essential to the result, than in rendering them conductors at the surface: for he has ascertained that the new substances are not generated till the interior, which is dry, begins to be fused.

The combustible bases of the fixed alkalies, seem to be repelled as other combustible substances, by positively electrified surfaces, and attracted by negatively electrified surfaces, and the oxygen follows the contrary order: or, the oxygen being naturally possessed of the negative energy, and the bases of the positive, do not remain in combination when either of them is brought into an electrical state opposite to its natural one.

After Mr. Davy detected the bases of the fixed alkalies, he found great difficulty in preserving and confining them so as to examine their properties; but he found that in recently distilled naptha they might be preserved some days with out much change. The basis of potash at 60° of Fahrenheit possessed the general appearance of mercury, so as not to be distinguished from it, but at that degree of temperature, it is only imperfectly fluid; at 70° it is more fluid, and at 100° its fluidity is perfect, so that different globules will run into one. At 500 it is soft and malleable, with the lustre of polished silver, and at the freezing point it becomes harder and brittle, and when broken into fragments, exhibits a crystallized texture, which by means of the microscope seems composed of beautiful facets of a perfect whiteness, and high metallic splendor. At a heat approaching requess, it is converted into vapour,

and is found unaltered after distillation. It is a perfect conductor of electricity. When a spark is taken from the Voltaic battery from a large globule; the light is green, and combustion takes place at the point of contact only. When a small globule is used, it is completely dissipated with explosion accompanied by a most vivid flame. It is an excellent conductor of heat; but resembling the metals in all these sensible properties, it is very different from any of them in specific gravity, being only as 6 to 10, compared with water, so that it is the lightest fluid body known.

With respect to chemical relations; it combines with oxygen, slowly and without flame, at all teinperatures below that of vaporization; but at this temperature combustion takes place, and the light is of a brilliant whiteness, and the heat intense. When a globule is heated in hydrogen gas at a degree below its point of vaporization, it seems to dissolve in it, for the globule diminishes in volume, and the gas explodes with alkaline fumesand bright light when suffered to pass into the air. When brought into contactwith water, it decomposes it with great violence; an instantaneous explosion is produced with bright flame, and a solution of pure potash is the result. When a globule of this substance is placed upon ice, it instantly burns with a bright flame, and a deep hole is made in the ice, which is found to contain a solution of potash.

Theory:-The phenomena seem to depend on the strong attraction of the potassium for oxygen; and of the potash for water. The heat which arises from two causes, decomposition and combination, is sufficiently intense to produce inflammation. The production of alkali in the decomposition of water by potassium, is shewn by dropping a globule of it upon moistened paper, tinged with turmeric. At the moment that the globule comes into contact with the water, it burns, and moves rapidly upon the paper, as if in search of moisture, leaving behind it a deep reddish brown trace, and acting upon the paper as dry caustic potash. So strong is the attraction of potash for oxygen, and so great the energy of its action upon water, that it discovers and decomposes the small quantities of water contained in alcohol and ether. Potash is insoluble in ether; but when potassium, the basis, is thrown into it, oxygen is furnished, and hydrogen gas is disengaged, and the alkali as it forms renders the

ether

ether white and turbid. In ether and alcohol the energy of its action is proportional to the quantity of water they contain, and hydrogen and potash are the constant result.

Potassium thrown into solutions of the mineral acids, inflames and burns on the surface. It readily combines with the simple and inflammable solids and with metals; with phosphorus and sulphur, forming compounds similar to the metallic phosphurets and sulphurets. When it is brought into contact with a piece of phosphorus, and pressed upon, there is a considerable action; they become fluid together, burn, and produce phosphate of potash. When potassium is brought into contact with sulphur in fusion in the atmosphere, a great inflainmation takes place and sulphuret of potash is formed. The sulphuretted basis becomes oxygenated by exposure to the air, and is finally converted into sul phate. When one part of potassium is added to 8 or 10 parts of mercury at about 600 of Fahrenheit, they instantly unite, and form a substance like mercury in colour, but less coherent, and small portions of it appear as flattened spheres. When a globule is made to touch a globule of mercury about twice as large, they combine with heat; the compound is fluid at the temperature of its formation; but when cool it appears as a solid metal, similar in colour to silver. If the potassium be still increased the amalgam becomes harder, and brittle. When the proportions are 1 of potassium and 70 of mercury the amalgam is soft and malleable. If the compounds are exposed to air, they rapidly absorb oxygen; potash which deliquesces is formed, and in a few minutes the mercury is found pure and unaltered. When a globule of amalgam is thrown into water, it rapidly decomposes it with a hissing noise; potash is formed, pure hydrogen is disengaged, and the mercury remains free. The action of potassium upon the inflammable oily compound bodies, confirms the other facts of the strength of its attrac

tion for oxygen. On recently distilled

naptha it has very little action; but in naptha that has been exposed to the air, it soon oxydates, and alkali is formed, which unites with the naptha, into a brown soap that collects round the globule. On concrete and fixed oils, when heated, it acts slowly, coaly matter is deposited, a little gas is evolved, and a soap is formed. By heat it rapidly decomposes the volatile oils.

Potassium readily reduces metallic oxides, when heated in contact with them: it decomposes readily flint and green glass, with a gentle heat; alkali is immediately formed by oxygen from the oxides which dissolves the glass, and a new surface is soon exposed to the agent.

We shall in our next, give a more detailed account of the decomposition of soda; and shall now present the reader with a short analysis of the application of the gas from coal to economical purposes by Mr. William Murdoch. This gentleman by means of coal-gas completely lighted up last winter, the cotton manufactory of Messrs. Phillips and Lee, at Manchester, the largest in the kingdom. The light used, was ascertained to be equal to that produced by 2500 mould candles of six to the pound. In this instance the coal was distilled in iron retorts, which were kept constantly at work, and the gas as it rose was conveyed by iron pipes into large reservoirs, where it was worked and purified, previously to its being conveyed through other pipes called mains to the mill. The burners, where the gas was consumed, were connected with the mains by short tubes, each of which was furnished with a cock to regulate the admission of the gas to each burner, and to shut it off when requisite. The burners were of two kinds the one was upon the principle of the Argand lamp, and resembled it in appearance, the other was a small curved tube with a conical end, having three circular apertures of about the th of an inch in diameter, through which the gas issued, forming three divergent jets of flame, somewhat like a fleur-delis. This tube, from its shape and appearance, was called the cockspur burner. In the whole building there were 271 argands, and 633 cockspurs; each of the former giving a light equal to four candles, and each of the latter a light equal to 24. All together require an hourly supply of 1250 cubic feet of gas, produced from cannel coal.

The whole annual expence, allowing 5501. for apparatus, is reckoned at 6001. but that of candles, to give the same light, would be 2000l. supposing candles one shilling per lb. only. This calculation was made on the supposition that the light was used only two hours per day, through the year, but if it be required three hours: the cost will be 6501. for gas, and 3000l. for candles. At first there was some inconvenience from the

smell

in a mill and sifts them as often as the process is found profitable. For the purpose of sifting, he uses a frame, about 6 or 7 feet long, two feet wide, and 5 inches deep, into which is fixed another frame or frames, with silk bottoms, through this by means of a velocity obtained by mechanical contrivances, the mustard is passed. The sieve is to be supplied by a hopper, placed above it, and to this Mr. Shotwell lays an exclusive claim. The sieve should be so hung that it may conveniently be brushed under the bottom, or brushes may be fixed the length of the sieve, to be moved by crank, by machinery, or any other way at pleasure.

Observations. The advantages de scribed as belonging to this invention are, 1. That a considerable quantity of genuine mustard is obtained from offal, hitherto deemed of little value. 2. An article possessing a considerable degree of pungency, is obtained from the brown mustard-seed, at a small expence. 3. By connecting a hopper or other apparatus, with the upper end of the sieve, the labour of supplying the sieve with meal is very much lessened, and the supply is more regular than when done by the hand; and by fixing long brushes under the sieve, the labour of brushing is much lessened.

R EDWARD DAMPIERS (PRIMROSESTREET, LONDON,) for Machinery for reducing Drugs, &c. into fine Powder, This machinery consists of a large wheel or flat surface, of iron or other metal, fixed to a vertical shaft or arbor, to be driven round by the powers commonly used in manufactures. Upon the face of the wheel, I attach, by screws, keys, bolts, &c. certain cutters or raspers, with their edges or faces toothed and directed upwards; each of which is fixed so that its length shall be directed to wards the shaft, either precisely, with such an obliquity, as that the line, of the length of each rasper, shall every where cross the circles described by the motion of its teeth; and close to each cutter or rasper, there is a perforation, or long hole, quite through the face of the wheel, for the purpose of permitting the rasped wood or other material to fall through. In the use and application of this machinery, the drugs, &c. are placed and secured upon the face of the said wheel, which by its rotation causes the teeth of the cutters to act upon the same, aud to cut off portions or raspings off the same, which fall through into a proper

receptacle. The wheel may be bevelled inwards, or outwards, and admits of va rious forms, dimensions, and velocities; and by various contrivances, all the cutters may be fixed upon the wheel at once, or a part of them may be separately attached, and taken out when needful. The drawings attached to this specification give a complete view of the business.

MR.

JOSEPH CUFF'S (WHITECHAPEL,) for a new Method of slaughtering Cattle, &c.

The title of this specification mentions cattle of divers descriptions, from oxen, downwards, but the drawings are confined to hogs. We have carefully examined the specification; and from that and the included drawings, we understand that Mr. Cuff keeps the animals to be killed in a certain kind of pen in the slaughter-house, and that two persons are employed in the business, or perhaps three; the occupation of one person, is to catch the beast, or by some other manoeuvre to fasten a rope or hook, on one or both of its hind legs; another person is then by means of a wheel and pulley, or other apparatus, to draw the animal up to a certain height, and a third person is to fix the rope on the tenter hooks, and while thus suspended with its head downwards, the animal's throat is to be cut.

Remark. The Patentee professes that the meat is better by this mode of slaugi. tering, than by the usual methods. We must, however, observe, that, if its suppo sed advantages arise from the mere position of the animal when killed, the invention is not new; it has been practised in a village within a mile north of London, some years. Nor do we see that there can be any novelty in the apparatus for dragging up the animal and suspending it by its hind legs, so as to warrant an exclusive claim. We are, from a view of the invention, induced to believe that the method will, in practice, he found much more cruel, than that usually adopted; and therefore cannot merit the applause and patronage of the public, who should endeavour to miti gate the sufferings of creatures whose lives are sacrificed to supply their wants.

MR. EDWARD THOMASON'S (BIRMING

HAM,) for a new Method of manufacturing Umbrellas, Parasols, &c. This gentleman has, we believe, been fortunate in his inventions which have been noticed in the Monthly Magazine.