CRUCIBLES.

381

creosote till it remains colorless, or nearly so, even upon exposure to air. It must benow dissolved in the strongest potash ley, subjected to distillation anew, and. lastly, re-distilled with the rejection of the first products which contain much water, retaining onlyH'e following, but taking care not to push the process loo far.

In operating upon pyroligneous acid, if we dissolve effloresced sulphate of so8a in it tosaturation, at the temperature of 167° F., the creosote oil will separate, and float uponthe surface. It is to be decanted, left in repose for some days, during which it will partJ'nth a fresh portion of the vinegar and salt. Being now saturated while hot, with car-bonate of potash, and distilled with water, an oily liquor is obtained, of a pale yellownolor. This is to he rectified by phosphoric acid, &c., like the crude product of creosote•fom tar.

Creosote is apparently composed of 76 - 2 carbon,7 - 8 hydrogen, and 16-0 oxygen, in 100Parts. It i s an 0 j]y looking liquid, slightly greasy to the touch, void of color, having anaerid burning taste, and capable of corroding the epidermis in a short time. It possesses^ Penetrating disagreeable smell, like that of highly smoked hams, and, when inhaled uphe nostrils, causes a flow of tears. Its specific gravity is T037, at 58° F. Its consist-® nc e is similar to that of oil of almonds. It has no action upon the colors of litmus ornrmeric, but communicates to while paper a stain which disappears spontaneously in ahours, and rapidly by the application of heat.

II boils without decomposition at 398° F., under the average barometric pressure,jPttiains fluid at 16° F., is a non-conductor of electricity, refracts light powerfully, andJ"ns in a lamp with a ruddy smoky flame.

,' v !'en mixed with water at 58° F. it forms two different combinations, the first being a^ ntion of 1 part of creosote in 400 of water; the second, a combination of 1 part of^ a ler with 10 parts of creosote. It unites in all proportions with alcohol, hydric ether,Pc ether, naptha, eupione, carburet of sulphur, &c.the ^° SOte d' ss °I ves a large quantity of iodine and phosphorus, as also of sulphur withbin ai< ^ heat, but it deposiles the greater, part of them in crystals, on cooling. It com-

eor> eS P otas h, soda, ammonia, lime, baryta, and oxyde of copper. Oxyde of mercury

Struts creosote into a resinous matter, while itself is reduced to the metallic state,b? sulphuric and nitric acids decompose it.

nnd^ e ° SOte < I' sso l ves several salts, particularly the acetates, and the chlorides of calciumr em ‘' n S it reduces the nitrate and acetate of silver. It also dissolves indigo blue; al ate r nable circumstance. Its action upon animal matters is very interesting. It coagu-p 0 * blbumen, and prevents the putrefaction of butchers’ meat and fish. For this pur-c rt . -se substances must be steeped a quarter of an hour in a weak watery solution ofthat q 1 ?’ then drained and hung up in the air to dry. Hence Reichenbach has inferredc orr ‘‘ *? owing to the presence of creosote that meat is cured by smoking ; but he is notwith 1 In ascr ibing the effect to the mere coagulation of the albumen, since fibrine alone,k‘Us°ni l creos °t e , will putrefy in the course of 24 hours, during the heats of summer. Itq and small animals. It preserves flour paste unchanged for a long time,

in exists in the tar of beech-wood, to the amount of from 20 to 25 per cent., and

( c Pyroligneous acid, to that of 1J.

gre s ,| >U ?*'t to be kept in well-stoppered bottles, because when left open it becomes pro-CY e V ‘ Sallow, brown, and thick.

teeth w'°£ e k as considerable power upon the nervous system, and has been applied to thediein a i advantage in odontalgia, as well as to the skin in recent scalds. But its me-is ren . ar "l surgical virtues have been much exaggerated. Its flesh-preserving quality'■Oparts™ **ttle use > from tlle difficulty of removing the rank flavor which it

r ow^^®k,ES {Creusets, Fr.; Schmelzticgel, Germ.) are small conical vessels, nar-sis, f or „™ e bottom than the mouth, for reducing ores in docimasy by the dry analy-Poundj na . USIns mixtures of earthy and other substances, for melting metals, and corn-acted uno 1116 ^* 0 They ought to be refractory in the strongest heats, not readily

“ ea rin» c tl the substances ignited in them, not porous to liquids, and capable ofthey sh’ 0 „j d ns! “ era * ) * e alternations of temperature without cracking; on which accountbtitted with ma ^ e t°o thick. The best crucibles are formed from a pure fire clay,

.hie po , ae -y ground cement of old crucibles, and a portion of black-lead or graphite.ln a simu._ colte m ay be mixed with the plumbago. The clay should be prepared

sl °Wly dripn as *° r ma 'ting pottery ware; the vessels after being formed must bebl ® Parts in u l * len P ro P er 'y baked in the kiln. Crucibles formed of a mixture

r a found , °f Stourbridge clay and cement, 5 of coke, and 4 of graphite, have

onndry. g , stand 23 meltings of 76 pounds of iron each, in the Royal Berlin. a ieh even wrn craci , es resisted the greatest possible heat that could be produced, in,^ n ooolinn witir lr0n was me Ited, equal to 150° or 155° Wedgewood; and bore sud-fnli„_.- 6 w *tnout crackine. AhmU. nmeihles is

fo 'lowiL' Vith 1 ° U Q t ( cracking. Another5 • a otourbndge clav

composition for brass-founding crucibles, isburned clay cement ? £ coke powder; £ pipe