vertically, assuming the magnetic meridian by its own action. The inventor is Mr. Lockwood of the navy.

6. Machine to Sweep Chimneys.

Mr. C. Carr of Paddington, has constructed a machine to sweep chimneys, which appears to possess great advantages. It is complete of itself, requiring no chain, pully, or other appendage in the chimney, and will sweep very clean as well in horizontal as perpendicular flues. If the flue be angular, having one or more bends, the person who uses it can ascertain the direction in which the angle goes off, and can turn the head of the instrument the proper way. There is a means also of ascertaining when the head of the instrument has reached the top of the chimney, so that no danger of thrusting off the iron smoke cowles is incurred. It works in a very cleanly manner entirely from below, and can easily be made fire proof when necessary.

7. Prevention of the Dry Rot.

Mr. John Shilliber, of Walkhampton near Plymouth, proposes to prevent the dry rot in timber, by cutting it down when all vegetation has entirely ceased, as at Christmas, instead of felling it immediately after the tree has recommenced its growing. In the last case it is said the pores are open and extended, the wood soft, the bark separates with ease, and when the juices of the tree have dried up, the pores remaining open, allow the wood to become infected with the disease. In the former the pores are considered as naturally closed, the sap and other easily changing fluids have descended into the root, or formed more solid matter, the bark adheres very closely and firmly to the wood, and the wood is much harder and more impenetrable, and is not affected by the dry rot. These conclusions have been drawn from a comparison of timber felled at different periods.

II. CHYMICAL SCIENCE.

§ I. CHYMISTRY.

1. Alkali from Potatoe Stalks.

The attention of the people of Ireland has been called to the extraction of potash from potato stalks. Processes for that

purpose have been commenced, and they promise to produce in that part of the British dominions a most important article of trade. It is calculated that 350,000 acres of land are annually cultivated with potatoes; these would produce 46,875 tons of potash, which, at £20. per ton, would amount to £937,500. per annum.

2. Tungstic Acid.

M. Chevreul has observed, that by heating the tungstate of ammonia with tincture of turnsole, the acid properties of the tungstic combination are rendered evident by the change of colour,

3. Copper dissolved in Hydrogen.

Hydrogen gas (says M. Lampadius) dissolves copper when it is passed over this metal in fine powder at a white heat. The gas then burns with a green flame, and forms, during its combustion, an oxide of copper.

4. Homberg's Pyrophorus.

Homberg's pyrophorus is said to be more certain in its preparation, when of sulphate of soda is added to the mixed alum and flour.

5. Test for Sugar.

It has been proposed by M. Doberenier, to test sugar in solution, in small quantities, by adding to a portion of the liquid, a few grains of yeast, and placing it in a vessel closed by mercury. A fermentation takes place, and the bulk of gas liberated indicates the quantity of sugar.

6. Temperature on and beneath the Surface of the Earth. The mean temperature of Paris, deduced from many years observation is 10° 6' of the centigrade scale, 51° Fahrenheit. The temperature of the cave beneath the Observatory has been for a long time 11° 71′ 54° Fahrenheit. What is the cause of this difference of more than 1o between two results, = 3° Fahrenheit, which according to theory, should correspond?

7. Uranium.

It has been ascertained by M. Chevreul that the peroxide of uranium is soluble in the alkaline sub-carbonates, and forms, with that of potash, a regularly crystallized salt. No carbonic

acid is disengaged. The solution is of a fine yellow colour, similar to that of the chromate of potash.

8. Chromic Oxide and Acid.

Chromic oxide heated with alkali becomes chromic acid, and chromic acid heated with an acid becomes chromic oxide; the oxide in solution is green, and the acid yellow, and the change of state and colour may be produced successively at pleasure.

9. Cocoa Nut Oil.

Cocoa nut oil is perhaps the most volatile of what are called the fixed oils; when heated, it distils over with scarcely any decomposition, and the part distilled, when washed, is similar to the original oil.

10. Wire Gauze Safety Lamp.

To show how far the security afforded by means of wire gauze might be applied to the procuring light in the mines, Sir H. Davy has lately made an Argand's lamp safe by means of it. It required no glass, the cylinder of gauze supplying its place. It, as was expected, answered perfectly.

11. Snake Stones.

Dr. Davy has lately analyzed the snake stones of India. He found them to be of three kinds; one was merely calcined bone; another carbonate of lime, coloured by a vegetable substance; and the third a bezoar stone. The idea entertained by the natives, of their power over the bite of poisonous snakes, is entirely unfounded.

12. Strength of Ale.

Ale brewed by Sir Joseph Banks, being analyzed at his desire by Mr. Brande, gave the following proportion of alcohol. 1. Malt to the hogshead 8 strike.* Hops to the hogshead 8 lbs. Brewed 11th January, 1816-contained 9.85 per cent. of alcohol.

2. Malt to the hogshead 10 strike. Hops to the hogshead 11 lbs. Brewed 27th February, 1815-contained 10.84 per cent. of alcohol.

By strike is meant a bushel measure of malt, not heaped up, but struck off to a level with the rim.

13. Change of Colour by Acids.

The effects of muriatic acid gas and ammoniacal gas upon turmeric paper, are so similar, that it is difficult to distinguish the two by this test alone. The acid reddens it almost as much as the alkali. Phosphoric, nitric, muriatic, and particularly sulphuric acid, also redden turmeric paper; but in all these cases, water, even in small quantities, immediately restores the original calour.

14. Yellow Die.

A chymist of Copenhagen is said to have discovered a brilliant yellow matter for dying in potato tops. The mode of obtaining it, is by cutting the top when in flower, and bruising and pressing it to extract the juice. Linen or woollen soaked in this liquor during 48 hours, takes a fine solid and permanent yellow die. If the cloth be afterward plunged in a blue die, it then acquires a beautiful permanent green colour.

15. Analysis of Sweet Almonds.

M. Boullay has given an analysis of sweet almonds as follows.

MM. Pelletier and Caventon have obtained a new acid from cholesterine or the pearly substance of human biliary calculi discovered by Poulletier-de-Laselle, and named by Chevreul. Cholesterine is to be heated with its weight of strong nitric acid until it ceases to give off nitrous gas. A yellow substance separates on cooling, scarcely soluble in water, and which, when well washed, is pure cholesteric acid.

It is soluble in alcohol, and may be crystallized by evaporation. It is decomposed by a heat above that of boiling water,

and gives products containing oxygen, hydrogen, and charcoal as their elements. It combines with bases, and forms salts. Those of potash, soda, and ammonia, are very soluble: the rest are nearly insoluble.

17. Metallic Manganese.

The properties of metallic manganese, reduced by M. Fischer of Schaffouse, are described in the Bibliothèque Universelle as follows:-The fracture is neither conchoidal nor crystallized, but irregular, and very similar to that of the sulphuret of iron, commonly called marcasite. The metal is of a white colour. It is harder than tempered steel, and cuts glass almost as well as the diamond. It is capable of scratching rock crystal. It takes a very fine polish, but the permanency is doubtful, in consequence of its affinity for oxygen. Placed in water for 24 hours, it becomes covered with a brown oxide. It acts sensibly on the magnetic needle, perhaps in consequence of a little iron. The specific gravity is 7.467.

18. Analysis of Bitter Almonds.

M. Vogel, in his experiments on and analysis of bitter almonds, gives the following proportions of the substances in

Essential oil and prussic acid,

The essential oil appears to be a very singular substance. It is best obtained by distilling almond water with barytes, to separate the prussic acid. In close vessels it is very volatile; exposed to the air, it becomes solid, crystalline, inodorous, and of considerable fixity. The crystals are a compound of it with oxygen, for oxygen is absorbed during their formation, and if they are dissolved in hydro-sulphuret of ammonia, they are again decomposed, and the original odour and oil is produced.