V E G

VAR ( 4 66 )

the poliflied furface over with the followingvarniih.

19. Take of fine white refin 4| lbs. of com-mon refin the fame quantity, of gum fandarach2^ lbs. and of common aloes 2 lbs.: melt thewhole over a gentle fire, ftirring them well atthe fame time with ah iron fpatula •, when thefufion is compleat add by degrees 7 pints oflinfeed oil,- and make the whole boil for fix orfeven hours, ftirring it carefully all the time.When the varnifh begins to get ropy, ftir inhalf an ounce of red lead finely pulverized : asfoon as this latter is compleatly dilfolved re-move the varnifh from the fire and ftrain itwhile warm through a linen or flannel bag.

VEGETABLE MATTER.

Having already noticed at length in theirproper places the different vegetable principles,and l'uch individual vegetable l'ubftances as havereceived any thing like an accurate chemicalanalyfis, there remain but a few words to befaid on the general fubjedt.

Vegetable matter, though in its ultimate ana-lyfis it is compofed for the molt part of oxygen,hydrogen, carbon, and azot, is made up of anumber of fecondary compounds, which welhall proceed to enumerate.

The raoft important of all, if we have regardto its quantity, in which it greatly exceeds allthe reft put together, is vegetable fibre or Woed.This is to plants what bone, mufcle, and cartilageare to animals; to this they are entirely indebtedfor their liability and the refiftance which theyare able to oppofe to external violence: it con-ftitutes the greater part of all woods and barks ;of the green epidermis of herbaceous plants, ofthe network of leaves, and of the fine downyfibres in which the feeds of cotton and variousother vegetables are imbedded. It confifts ofcarbon, oxygen, hydrogen, and a little azot.By dry diftillation it yields hydro-carbonousgas, carbonic acid, empyreumatic acetous, orpyroligneous acid, with a little ammonia, and alittle volatile oil; a large proportion of char-coal remains behind in the retort, ftill exhibit-ing in a very perfedl manner the texture ofthe wood. There is no animal fubftance at allanalogous to vegetable fibre.

The next perhaps in quantity is fecula orftarch. It is contained in all feeds, and morefparingly in moft of the bulbous, tuberous, andother flefhy roots. It is not afeertained whetherazot enters into its compofition; it certainlyhowever affords no ammonia by dry diftillation.It appears to be abfolutely peculiar to the vege-table kingdom.

Extract is another of the peculiar vegetableprinciples ; but though nothing analogous to itexifts in the animal kingdom, yet it afford*ammonia both by dry diftillation and by theaction of quicklime; in the former cafe indeedthe ammonia is mafked by the contemporaneousproduction of empyreumatic acid, but it mayreadily be fet at liberty by means of the fixedalkalies.

Another vegetable principle is Tannin : it iscontained in certain barks, woods, and leaves,and affords by dry diftillation an empyreumaticacid but no ammonia. It may be confidered a*peculiar to vegetables, although it appears fromMr. Hatchett’s experiments that a fubftancevery fimilar to tannin may be procured by theadtion of nitric acid on various kinds of animalmatter previoufly charred.

Gum mucilage is another of the peculiar vege-table principles to which nothing analogous hasyet been difeovered in the animal kingdom : itrefides chiefly in the barks of trees, and in afew of the bulbous roots. By dry diftillationit affords an empyreumatic acid, from whichhowever quicklime fets at liberty a quantity ofammonia, thus fhowing that azot enters intothe compofition of this fubftance.

Volatile oil is alfo peculiar to the vegetablekingdom : it occurs in the bark, the wood, andthe covering of feveral feeds: it appears to con-fift entirely of oxygen, hydrogen, and carbon f itdoes not afford any ammonia by diftilla ion.

Camphor , Rejin, and Balfam alfo rank amongthe peculiar vegetable principles, and appear toconfift of oxygen, hydrogen and carbon, with-out any azot. A few of the aromatic animalproducts indeed, fuch as mufk, civet and am-bergris appear to contain a portion of refin,which however differs from vegetable refin inaffording ammonia by digeftion with fixed alkali,and therefore contains azot.

Gum refin, Gluten and Caoutchouc , arc three pe-culiar vegetable principles, into the compofitionof which a confiderable quantity of azot enters,as they afford ammonia and oil by dry diftilla-tion, but no acid.

The acids peculiar to vegetables are the tar-taric , citric and gallic, the malic , oxalic, acetic andprujfic ; of thefe however the four latter, thoughnot originating in animal organization, may yetbe produced by the adtion of diff erent re-agemson fevera’i animal produdts.

The fubftances common to both vegetableand animal matter are the following, viz.

Sugar. This is contained largely in theitems of feme of the graffes, in the nedtaries of

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