On naphtha colourless and recently distilled, as I have already said, it has very little power of action; but in naphtha that has been exposed to the air it soon oxydates, and alkali is formed, which unites with the naphtha into a brown soap that collects round the globule.

*

On the concrete oils, (tallow, spermaceti, wax, for instance,) when heated, it acts slowly, coaly matter is deposited, a little gas is evolved, and a soap is formed; but in these cases it is necessary that a large quantity of the oil be employed. On the fluid fixed oils it produces the same effects, but more slowly.

By heat likewise it rapidly decomposes the volatile oils; alkali is formed, a small quantity of gas is evolved, and charcoal is deposited.

When the basis of potash is thrown into camphor in fusion, the camphor soon becomes blackened, no gas is liberated in the process of decomposition, and a sapona

* When a globule of the basis of potash is introduced into any of the fixed oils heated, the first product is pure hydrogen which arises from the decomposition of the water absorbed by the crust of potash during the exposure to the atmosphere. The gas evolved, when the globule is freed from this crust, I have found to be carbonated hydrogen requiring more than an equal bulk of oxygen gas for its complete saturation by explosion. I have made a great number of experiments, which it would be foreign to the object of this lecture to give in minute detail, on the agencies of the basis of potash on the oils. Some anomalies occurred which led to the enquiry, and the result was perfectly conclusive. Olive oil, oil of turpentine, and naphtha, when decomposed by heat, exhibited as products different proportions of charcoal, heavy inflammable gas, empyreumatic oily matier, and water, so that the existence of oxygen in them was fully proved; and accurate indications of the proportions of their elements might be gained by their decomposition by the basis of potash. Naphtha of all furnished least water and carbonic acid, and oil of turpentine the most.

ceous

ceous compound is formed; which seems to shew that camphor contains more oxygen than the volatile oils.

The basis of potash readily reduces metallic oxyds when heated in contact with them. When a small quantity of the oxyd of iron was heated with it, to a temperature approaching its point of distillation, there was a vivid action; alkali and grey metallic particles, which dissolved with effervescence in muriatic acid, appeared. The oxyds of lead and the oxyds of tin were revived still more rapidly; and when the basis of potash was in excess, an alloy was formed with the revived metal.

In consequence of this property, the basis of potash readily decomposes flint glass and green glass, by a gentle heat; alkali is immediately formed by oxygen from the oxyds, which dissolves the glass, and a new surface is soon exposed to the agent.

At a red heat even the purest glass is altered by the basis of potash: the oxygen in the alkali of the glass seems to be divided between the two bases, the basis of potash and the alkaline basis in the glass, and oxyds, in the first degree of oxygenation, are the result. When the basis of potash is heated in tubes made of plate glass filled with the vapour of naphtha, it first acts upon the small quantity of the oxyds of cobalt and manganese in the interior surface of the glass, and a portion of alkali is formed. As the heat approaches to redness it begins to rise in vapour, and condenses in the colder parts of the tube; but at the point where the heat is strongest, a part of the vapour seems to penetrate the glass, render ing it of a deep red-brown colour; and by repeatedly distilling and heating the substance in a close tube of this kind, it finally loses its metallic form, and a thick brown crust, which slowly decomposes water, and which

combines

combines with oxygen when exposed to air forming alkali, lines the interior of the tube, and in many parts is found penetrating through its substance *

. In my first experiments on the distillation of the basis of potash, I had great difficulty in accounting for these phenomena; but the knowledge of the substance it forms in its first degree of union with oxygen, afforded a satisfactory explanation,

TO BE CONCLUDED IN OUR NEXT.

List of Patents for Inventions, &e.

(Continued from Page 72.)

REBECCA EBECCA CHING, of Rush Common, in the parish of St. Mary Lambeth, in the county of Surrey, widow of John Ching, late of Cheapside, in the City of London, Apothecary; for certain improvements in a medicine now ealled Ching's worm-destroying lozenges, for which her said late husband obtained letters patent, bearing date June 28, 1796. Dated May 7, 1808. Specification to be enrolled within one month.

JOHN HARRIOTT, of Wapping, in the county of Middlesex, Esq.; for a new fire-escape, or machinery to be used in case of fire. Dated May 10, 1808. Specification to be enrolled within one month.

WILLIAM HUNT, of the Brades, in the parish of Rowley Regis, in the county of Stafford, Iron Master; for

This is the more obvious explanation in the present state of our Anowledge; but it is more than probable that the silex of the glass likewise suffers some change, and probably decomposition. The subject I hope to be able to resume on another occasion.

a method

a method of rolling moulds or plates of trowels from pieces of either blister, sheer, or cast-steel; of a square or nearly square, or oblong form. Dated May 10, 1808, Specification to be enrolled within one month.

JOHN WATSON, late of Bury-place, Bloomsbury, in the county of Middlesex, Gent. but now a prisoner in the King's-bench Prison; for certain improvements in the art of soap-making, by which the article is in several respects ameliorated. Dated May 10, 1808. Specification to be enrolled within one month.

CHESTER GOULD, of the parish of St. Luke, Oldstreet, in the county of Middlesex, Gent. for certain improvements in the construction of a machine for washing or cleansing linen and various other articles, Dated May 17, 1808. Specification to be enrolled within four months.

WILLIAM CONGREVE, of Garden-court, Temple, in the county of Middlesex, Esquire; for a gun-carriage of the simplest construction, either for land or sea service, calculated to reduce very considerably the labour of working the gams, to produce a smooth and even recoil, and to prevent the violent action that takes place in common carriages when the gun is fired; at the same time the carriage is of much lighter, less expensive construction, and less liable to be struck and splintered by the enemy's shot, as presenting much less surface; when applied to the sea-service, it allows, moreover, of a very considerable reduction in the size of the port. Dated May 24, 1808. Specification to be enrolled within one month.

JOHN

JOHN STEDMAN, of Horton Kirby, in the county of Kent, Farmer; for a patten and clog of infinite utility and ease to such persons who may wear them. Dated May 24, 1808. Specification to be enrolled within one month.

WILLIAM HENRY POTTER, of No. 5, Pemberton-row, Gough-square, in the City of London, Flute-maker; for certain new improvements in German flutes and other wind musical instruments. Dated May 28, 1808. Specification to be enrolled within one month.

JOSEPH WILLMORE, of Birmingham, in the county of Warwick, Silversmith; and JOHN TONKS, of the same place, Plater; for a new method and processes in the manufacturing of nails. Dated May 28, 1808. Specification to be enrolled within one month.

ROBERT RANSOME, of Ipswich, in the county of Suffolk, Iron-founder; for his improvements on the wheel and swing plough. Dated May 30, 1808. Specification to be enrolled within one month.

DAVID THOMAS, of Featherstone-buildings, in the county of Middlesex, Gentleman; for a perforated vessel, percolater and frame, for making or preparing pottable coffee. Dated May 30, 1808. Specification to be enrolled within one month.