A Dictionary of Arts: Carbon.

A Dictionary of Arts, Manufactures, and Mines; containing A Clear Exposition of Their Principles and Practice

by Andrew Ure, M. D.;
F. R. S. M. G. S. Lond.: M. Acad. M. S. Philad.; S. PH. DOC. N. GERM. Ranow.; Mulh. Etc. Etc.

Illustrated with nearly fifteen hundred engravings on wood
Eleventh American, From The Last London Edition.
To which is appended, a Supplement of Recent Improvements to The Present Time.

New York: D Appleton & company, 200 Broadway. Philadelphia: George S. Appleton, 148 Chestnut St.
MDCCCXLVII

1847


CARBON. (Carbone, Fr.; Kohlenstoff, Germ.), in a perfectly pure state, constitutes diamond. Carbonaceous substances are usually more of less compound, containing hydrogen, or sometimes oxygen, and azote, along with earthy and metallic matters. Carbon, tolerably pure, abounds in the mineral kingdom; and, in a combined state, if forms a main constituent of vegetable and animal bodies. anthracite is a mineral charcoal, differing from common pit-coal in containing no bitumen, and therefore burning without flame or smoke. Coke is the carbonaceous mass which remains after pit-coal has been exposed to ignition fro some time out of contact of air; its volatile parts having been dissipated by the heat. It is a spongy substance, of an iron-black color, a somewhat metallic lustre, and does not easily burn unless several pieces are kindled together. With a good draught, however, it produces a most intense beat. Wood charcoal is obtained by the calcination of wood in close vessels, as described under the article ACETIC ACID, or in piles of various shapes, covered with loam, to screen it from the free action of the atmosphere, which would otherwise consume it entirely. See CHARCOAL. Such carbon is a solid, without smell or taste, and bears the strongest heats of our furnaces without suffering any change, provided air be excluded: it is a bad conductor of heat, but conducts electricity very well. When burned, it unites with oxygen, and forms carbonic acid, the fixed air of Dr. Black, the choke-damp of the miner. When this carbonic acid is made to traverse red hot charcoal it dissolves a portion of it, and becomes carbonic oxyde, which contains only one half of its volume of oxygen; whereas carbonic acid consists of one volume of oxygen combined with one volume of the vapor of carbon, the two being condensed into one volume. If the specific gravity of oxygen = 1.1025, be deducted from that of carbonic acid, = 1.5245, the difference, = +.422, will be the specific gravity of the vapor of carbon; as well as the proportion present in that weight of the acid.

Charcoal obtained by the action of a rapid fire in close vessels is not so solid and so good a fuel as that which is made in the ancient way by the slow calcination of pyramidal piles covered with earth. One of the most economical ovens for making wood charcoal is that invented by M. Foucauld, which he calls a shroud, or abri. To construct one of these, 30 feet in diameter at the base, 10 feet at its summit, and from 8 to 9 feet high, he forms, with wood 2 inches square, a frame 12 feet long, 3 feet broad at one end, and one foot at the other. The figure will explain the construction. The uprights, A B and C D, of this frame are furnished with three wooden handles a a a, and a' a' a', by means of which they can be joined together, by passing through two contiguous handles a wooden fork, the frame being previously provided with props, as shown in fig. 259, ad covered with loam mixed with grass. A flat cover of 10 feet diameter, made of planks well joined, and secured by four cross bars, is mounted with two trap doors, M N, fig. 261, for giving egress to the smoke at the commencement of the operation; a triangular hole P, cut out in the cover, receives the end of a conduit Q R S, (Figs. 262 and 261,) of wood formed of three deals, destined to convey the gases and condensed liquids into the casks F G H. Lastly, a door T, which may be opened and shut at pleasure, permits the operator to inspect the state of the fire. The charcoal calcined by this abri, has been found to be of superior quality.



When it s wished to change the place where the abri is erected, and to transport it to a store of new-felled timber, the frame is taken down, after beating off the clay which covers it, the joints are then cut by a saw, as well as the ends of the forks which fixed the frames to one another. This process is economical in use, simple and cheap in construction; since all the pieces of the apparatus are easily moved about, and may be readily mounted in the forests. For obtaining a compact charcoal, for the use of artisans, this mixed process of Foucauld is said to be preferable to either the close iron cylinder or the pile.

For making gunpowder-charcoal the lighter woods, such as the willow, dogwood, and alder answer best; and in their carbonization care should be taken to let the vapors freely escape, especially towards the end of the operation, for when they are re-absorbed, they greatly impair the combustibility of the charcoal.

By the common process of the forests, about 18 per cent. of the weight of the wood is obtained; by the process of Foucauld about 24 per cent. are obtained, with 20 of crude pyroligneous acid of 10 degrees Baumé. By the process described under ACETIC ACID, 27 of charcoal, and 18 of acid at 6 degrees, are procured from 100 parts of wood, besides the tar. These quantities were the results of careful experimenting, and are greater than can be reckoned upon in ordinary hands.

Charcoal for chemical purposes may be extemporaneously prepared by calcining pieces of wood covered with sand in a crucible, till no more volatile matter exhales.

The charcoal of some woods contains silica, and is therefore useful for polishing metals. Being a bad conductor of heat, charcoal is employed sometimes in powder to encase small furnaces and steam-pipes. It is not affected by water; and hence the extremities of stakes driven into moist ground are not liable to decomposition. In like manner casks when charred inside preserve water much better than common casks, because they furnish no soluble matter for fermentation or for food to animalcules.

Lowitz discovered that wood charcoal removes offensive smells from animal and vegetable substances, and counteracts their putrefaction. He found the odor of succinic and benzoic acids, of bugs, of empyreumatic oils, of infusions of valerian, essence of wormwood, spirits distilled from bad grain, and sulphureous substances were all absorbable by freshly calcined charcoal properly applied. A very ingenious filter has been constructed for purifying water, by passing it through strata of charcoal of different fineness.

When charcoal is burned, one third of the heat is discharged by radiation, and two thirds by conduction.

The following table of the quantity of charcoal yielded by different woods was published by Mr. Mushet, as the result of experiments carefully made upon the small scale. He says, the woods before being charred were thoroughly dried, and pieces of each kind were selected as nearly alike in every respect as possible. One hundred parts of each sort were taken, and they produced as under: -
Lignum Vitæ afforded 26.0 of charcoal of a grayish color, resembling coke.
Mahogany - - - 25.4 tinged with brown, spongy and porous.
Laburnum - - - 24.5 velvet black, compact, very hard.
Chestnut - - - 23.2 glossy black, compact, firm.
Oak - - - 22.6 black, close, very firm.
Walnut - - - 20.6 dull black, close, firm
Holly - - - 19.9 dull black, loose and bulky.
Beech - - - 19.9 dull back, spongy, firm.
Sycamore - - - 19.7 fine black, bulky, moderately firm.
Elm - - - 19.5 fine black, moderately firm.
Norway Pine - - - 19.2 shining black, bulky, very soft.
Sallow - - - 18.4 velvet black, bulky, loose and soft.
Ash - - - 17.9 shining black, spongy, firm.
Birch - - - 17.4 velvet black, bulky, firm.
Scottish Pine - - - 16.4 tinged with brown, moderately firm.

Mssrs. Allen and Pepys, from 100 parts of the following woods, obtained the quantities of charcoal as under: -
Beech - - - 15.00
Mahogany - - - 15.75
Lignum Vitæ - - - 17.254
Oak - - - 17.40
Fir - - - 18.17
Box - - - 20.25

It is observable that the quantities obtained by Messrs. Allen and Pepys are in general less than those given by Mr. Mushet, which may be owing to Mr. Mushet not having applied sufficient heat, or operated long enough, to dissipate the aqueous matter of the gaseous products.

To those persons who buy charcoal by weight, it is important to purchase it as soon after it is made as possible, as it quickly absorbs a considerable portion of water from the atmosphere. Different woods, however, differ in this respect. Messrs. Allen and Pepys found, that y a week's exposure to the air, the charcoal of
Lignum Vitæ gained - 9-6 per cent.
Fir - - - 13.0 ditto.
Box - - - 14.0 ditto.
Beech - - - 16.3 ditto.
Oak - - - 16.5 ditto.
Mahogany - - - 18.0 ditto.

The following is a tabular view of the volumes of the different gases which were absorbed in the course of 24 hours, by one volume of charcoal, in the experiments of M. Theodore de Saussure, which were conducted in a way likely to produce correct results. Each portion of charcoal was heated afresh to a red heat, and allowed to cool under mercury. When taken from the mercury, it was instantly plunged into the vessel of gas:

Ammoniacal gas - - - 90
Muriatic acid gas - - - 85
Sulphurous acid - - - 65
Sulphurated hydrogen - - - 55
Nitrous oxyde - - - 40
Carbonic acid gas - - - 35
Bicarburetted hydrogen - - - 35.00
Carbonic oxyde - - - 9.42
Oxygen gas - - - 9.25
Nitrogen - - - 7.50
Carburetted hydrogen - - - 5.00
Hydrogen gas - - - 1.75

Neumann, who made many experiments on charcoal, informs us, that for the reduction of the metallic oxydes, the charcoal of the heavier woods, as that of the oak and the beech, is preferable, and that, for common fuel, such charcoal gives the greatest heat, and requires the most plentiful supply of air to keep it burning; while those of the lighter woods preserve a glowing heat with a much less draught of air; and that for purposes where it is desirable to have a steady and still fire, charcoal should be employed which has been made from wood previously divested of its bark, since it is the cortical part which crackles and flied off in sparks during combustion, while the coal of the wood itself seldom does.

For making crayons of charcoal, the willow is the best wood that can be employed, as the softness is uniform in all its parts. Its durability may be seen in several of our old churchyards, where the letters made with lamp-black are still perfect, though the white head with which the body of the stones was painted is entirely destroyed.

This property of carbon is shown, however, in a more striking manner by the writings that were found in the ruins of Herculaneum, which have retained their original blackness for two thousand years. The ancients wrote with ink made from ground charcoal.

If it be required to purify any carbonaceous matter, to render it fitter for delicate pigments, which may be done by first calcining it in a close vessel, and then lixiviating it in water slightly acidulated by nitric acid.

The incorruptibility of charcoal was well known to the ancients, and they availed themselves of this property upon all important occasions.

About sixty years ago a quantity of oak stakes were found in the bed of the Thames, in the very spot where Tacitus says that the Britons fixed a vast number of such stakes to prevent the passage of Julius Caesar and his army. These stakes were charred to a considerable depth, had retained their form completely, and were firm at the heart.

Most of the houses in Venice stand upon piles of wood, which have all been previously charred for their preservation. In this county, estates were formerly marked out by charred stakes driven to a considerably depth into the ground. See BONE-BLACK, CHARCOA;L, and GRAPHITE.