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the formation of any intermediate acid: a phenomenon hitherto unexplained, because vinegar was considered as the most oxigenized of all the acids.

A hundred parts of common resin contain

Constituent principles of common resin,

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Vegetation so

These results evince a very important truth, which is,

lidifes water, that vegetables, in the act of vegetating, solidify water

entire, or its principles: for, all vegetables being almost or its princi» wholly composed of woody fibres and mucilage, which con- ples. tain oxigen and hidrogen in the same proportions as water;

it is evident, that, being taken into the vegetable, it combines with charcoal to forin them.

If therefore it were in our power to unite these two sub- Requisites to stances in all proportions, and to bring their particles to the fabrication of vegetable a suitable degree of approximation, we should be able matters. to make with certainty all the vegetable substances, that occupy the mean between acids and resins, as sugar, starch, woody fibre, &c.

Of animal substances we have hitherto analysed only Animal sub. fibrin, albumen, gelatin, and caseous matter.

stances ana

lysed.

General con

It follows from our analysis, that, in these four substances, and probably in all similar animal substances, hidrogen clusions. is in a larger proportion to oxigen than in water: that, the greater the excess of hidrogen they contain, the greater too is the quantity of nitrogen found in them: that these two quantities are almost in the same proportion as in ammonia; and it is probable, that this proportion, to which we come near, really exists; particularly as we always find a little too much hidrogen, and all the errours, to which we are liable, tend to increase the quantity of this principle. The reader may judge of this from the two following analyses. A hundred parts of fibrin contain

Carbon

Hidrogen and oxigen in the proportions that form

Constituent 51-675 principles of fibrin.

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Admitting

Analogies between the ani

mal and vege table kingdom.

The subject to be pursued.

Admitting this proportion, these substances would corre spond, with regard to the rank they hold among animal substances, to the rank occupied by sugar, gum, woody fibre, &c., among vegetable substances: for, as hidrogen and oxigen, the gaseous principles of these, are capable of mutually saturating each other, and forming water; hidrogen, oxigen, and nitrogen, the gaseous principles of those, can also mutually saturate each other, and form water and ammonia: so that carbon, the only fixed principle they all contain, has no property that acts in this saturation. If we allow ourselves to be guided by analogy, in this point of view, we should compare the animal acids with the vegetable acids; and the animal fats, if there be any that contain nitrogen, with vegetable oils and resins; consequently there is not a sufficient quantity of hidrogen in the uric acid to saturate the oxigen and nitrogen this acid contains, or to form water and ammonia by combining with these two substances; and in animal fats the contrary must occur,

No doubt many more consequences may be drawn from the preceding results: but we reserve for a future paper this inquiry, of the extent and importance of which we are fully aware.

Pieces of iron

adhering to the sides of

the furnace,

XI.

Chemical Examination of a white, filamentous Substance, found in the Cavities of the Cast Iron that adheres to the Sides of high Furnaces: by Mr. VAUQUELIN*.

IN smelting iron ores there are frequently portions of me

tal, which, beginning to assume the character of iron, and congealing the moment before the iron is drawn off, remain and containing adhering to the sides of the furnace. In these pieces cavities are frequently formed, which are filled with a white filamentous substance, like flexible amianthus.

a white sub

stance,

supposed to be

axide of zinc.

Several metallurgists have spoken of this substance. Grignon in particular hasconsidered it as an oxide of zinc:

Aun. de Chim. vol. XXVII, p. 192. Extracted from the Ann. des Museum d'Hist. Nat. An. 7,

but

but he, no doubt, relied on the external appearance, for it does not contain an atom of this metal.

To satisfy himself whether it were really oxide of zinc, It is not soluMr. Vauquelin boiled some with different acids, but none ble in acids. of them had any action on it: they did not dissolve an atom. This led to a doubt of the truth of the assertion of metallurgists respecting it: and the following experiment convinced him, that they were altogether mistaken.

Having heated this substance with thrice its weight of Treated with caustic potash in a silver crucible, it was completely fused, potash, and the mass produced was entirely dissolved by water. and muriatic The solution supersaturated with very dilute muriatic acid, acid did not become tarbid, but was converted into a white transparent jeily by evaporation, which is never the case with zinc.

When this was perfectly desiccated, and the residuum treated with water, a white powder was obtained, which, when washed and dried, did not differ from the original quantity taken a hundredth and half.

to be silex.

This powder exhibited all the characters of the purest it was found silex. No other earth existed in the liquor from which it had been separated, and not even any sensible quantity of oxide of iron.

The difficulty consisted not in finding the nature of this How is it sesubstance, but how it was formed in the cavities of the iron, parated? How indeed are we to conceive, that the silex, which is always mixed with alumine and lime both in the ores of iron, and in the fluxes employed, should have separated from these earths in a state of such perfect purity, that no perceptible quantity of foreign matter can be discovered with it?

sublimation.

The filamentous, and as it were crystallized state of this Apparently by silex announces, that it was converted into vapour by the violence of the fire, and afterward geatly condensed in the parts of the furnace that were less hot.

This would prove, not only that silex is volatile at a sufficient temperature, but that it is more so than alumine or lime; unless we suppose these two earths to have been raised to a greater height, which is not probable.

Aurrknot appletree.

Its good qua lities.

It hears in a

XII.

An Account of the Burrknot Apple. In a Letter to HENRY
GRIMSTON, Esq. F. H. S. By the Rev. JOHN SIMPSON*,

MY DEAR SIR,

YOUR letter met me on my return home after a month's

ramble among the mountains and lakes in Cumberland, and I now send you a short description of the apple tree called here the burrknot. At a proper season I will forward to you a few knots, or knobs of it, for trial, which, put into the ground, will make a long shoot, the following spring; or, if you wish it, I will send you a few knobbed branches with blossom buds upon them, which will bear a little the same year, but you must observe the smaller knobbed branches with blossom buds will not make such fine or handsome trees as the others,

The burrknot apple treet is uncommonly productive. My trees never miss bearing, not being so liable to blight in inclement seasons, as other varieties. The fruit is large, its tints resembling the ribston pippin, and about its size. For culinary uses, it is not inferior to the choicest codlin, and a much better keeper. The tree is not liable to canker, owing, I am persuaded, to its not putting out a tap root, but spreading its numerous fibres from the knob horizontally, and following the richness of the soil,

Our late worthy and valuable friend, Sir Christopher year's growth. Sykes, observing my trees of one year's growth with fruit upon then, was astonished, and the following year had the pleasure of exhibiting some of the knobbed branches, which I gave him, adorned with fruit in his own garden to his friends, of which you have probably been an eye witness, having visited so frequently in his time at Sledmere, If you wish for any other information that I can give respecting this apple tree, I shall be happy to send it, and remain, Dear sir,

Rooss, near Patrington,
July 25th, 1808.

Yours very truly,

JOHN SIMPSON.

• Trans. of the Horticultural Soc. Val. I, p. 120,

Specimens of the fruit, and branches of this apple tree from Rooss, which is also plentiful in Lord Hawkesbury's garden at Combe, were exhibited at the meeting of the Society, held Dec. 6th,

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