CARBON.
261
and benzoic acids, of bugs, of empyreumatic oils, of infusions of valerian, essence ofwormwood, spirits distilled from bad grain, and sulphureous substances were all absorb-able by freshly calcined charcoal properly applied. A very ingenious filter has been con-structed for purify ing 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 twothirds by conduction.
The following table of the quantity of charcoal yielded by different woods was pub-fished 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"’ere selected as nearly alike in every respect as possible. One hundred parts of eachsort were taken, and they produced as under:—
Lignum Vita: affordedMahogany -LaburnumChestnut -Oak -
Walnut - - -
Holly -
Beech -Sycamore -Elm -
Norway PineSallow -Ash - - -
26-0 of charcoal of a grayish color, resembling coke.25-4 tinged with brown, spongy and porous.
24-5 velvet black, compact, very hard.
23'2 glossy black, compact, firm.
22-6 black, close, very firm.
20-6 dull black, close, firm.
19-9 dull black, loose and bulky.
19-9 dull black, spongy, firm.
19-7 fine black, bulky, moderately firm.
19-5 fine black, moderately firm.
19-2 shining black, bulky, very soft.
18-4 velvet black, bulky, loose and soft.
17-9 shining black, spongy, firm.
17-4 velvet black, bulky, firm.
16-4 tinged with brown, moderately firm.
, * ^ essr s. Allen and Pepys , from 100 parts of the following woods, obtained the quanti-°f charcoal as under:—
BeechMahoganyLignum Vitse -
| ess 13 observable that the quantities obtained by Messrs. Allen and Pepys are in generalUp .. ®n those given by Mr. Mushet, which may be owing to Mr. Mushet not havingg a !ea sufficient heat, or operated long enough, to dissipate the aqueous matter of therp“ u s Products.
after* •! l ’- ose P er sons who buy charcoal by weight, it is important to purchase it as soonthe a t 1S ma de as possible, as it quickly absorbs a considerable portion of water fromPep ® os Phere. Different woods, however, differ in this respect. Messrs. Allen and■ound, that by a week’s exposure to the air, the charcoal of
- 15-00
- 15-75
- 17-25
OakFir -Box
- 17-40
- 18-17
- 20-25
Lignum Vita::Fir
Box -Beech -Oak -Mahogany -
-ained
9-6 per cent.
- 13-0
- 14-0
- 16-3
- 16-5
- 18-0
ditto.
ditto.
ditto.
ditto.
ditto.
The
"bsorb* 3 a tabular view of the volumes of the different gases which wereM. T|i eo i m t * le c °nrse of 24 hours, by one volume of charcoal, in the experiments ofr csult s . p re , ( * e Saussure, which were conducted in a way likely to produce correctUnder rnpe.!!!. 1 P° r, '°n of charcoal was heated afresh to a red heat, and allowed to coolWhen taken from the mercury, it was instantly plunged into the vessel
of g as “ erCUry -
Ammoniacal gas -Mwiatrc acid aas -Sulphurous acid^Iphureted hydrogencitrous oxyde - '
Carbonic acid gas -
90
Bicarbureted hydrogen -
35-00
85
Carbonic oxyde . -
9-42
65
Oxygen gas -
9-25
55
Nitrogen -
7-50
40
Carbureted hydrogen
5-00
35
Hydrogen gas
i-75
J the metallic oxvde« e t? an ^ ex P er tments on charcoal, informs us, that for the reductioneec b, is preferable and t'n c ^ arc °al of the heavier woods, as that of the oak and thea 9nires the most nlentif i**’ *" or comm °n fuel, such charcoal gives the greatest heat, andwn°^ s P res crve a glowini> U n SU PP*7 °f a > r to keep it burning; while those of the lighterere it is desirable to ban ( ' a1 ' "nth a much less draught of air; and that for purposese a steady and a still fire, charcoal should be employed which