218

RESINS.

Mr. Arthur Wall has recently obtained a patent, is founded upon the well-establisheufact, that when a compound is subjected to an electrical current, its negative and posi-tive elements are detached from one another. Crude iron contains more or less carbon,sulphur,-phosphorus, arsenic, oxygen, and silicon—bodies all electro-negative in vela-- tion to iron, which is electro-positive. When the impure iron, as it flows from theblast furnaces, is subjected during its cooling and consolidation to a powerful stream ofvoltaic electricity, the chemical affinities by which its various heterogeneous componentsare firmly associated, are immediately subverted, whereby, in the case of crude iron, thesulphur, phosphorus, &c., which destroy or impair its tenacity and malleability, becomereadily separable in the act of puddling. On this principle, I would explain the extra-ordinary effect of Mr. Wall’s patent electric process, as performed in my presence i |!the excellent iron-works of Mr. Jessop, at Codner Park, Derbyshire, where the elec-trised forge pigs discharged those noxious elements so copiously in the puddling fur-nace, as to become after a single reheating, without piling or fagoting, brilliant barsof the finest fibrous metal. The bars so made have been subjected, under my inspec-tion, to the severest proofs by skilful London blacksmiths, and they have been found tobear piercing, hammering, bending, and twisting, as well as the best iron in the market-I have also analyzed the said iron with the utmost minuteness of chemical research,and have ascertained it to be nearly pure metal, containing neither sulphur nor phosphorus, and merely an inappreciable trace of arsenic.- I can therefore conscientious!'recommend Mr. Wall’s patent process to iron-masters as one of the greatest, easiest, andmost economical improvements, which that important art has ever received.

The pecuniary advantage of this process, in respect of saving of labor and waste ofmaterial, has been estimated by competent judges at from one pound to two poundssterling per ton.

The effect of electrising iron is displayed in a singular manner by the conversion intosteel of a soft rod, exposed in contact with coke, for a few hours, to a moderate redheat; a result which I have witnessed and can fully attest.

PURPLE OF CASSIUS is best made according to the French Pharmacopm 18 'by dissolving 10 parts of acid chloride of gold in 2,000 parts of distilled water; prepaying in another vessel a solution of 10 parts' of pure tin in 20 of muriatic acid, which ■=diluted with 1,000 of water, and adding this by degrees to the gold solution as long a 'a precipitate is formed. The precipitate is allowed to subside, and is to be washed himeans of decantation : it is then filtered and dried at a very gentle heat.

R.

REFINING OF SILVER. In this process, as effected by sulphuric acid,arrangements are so complete, that a two thousandth part, or even less, of gold istraded free of charge to the bullion merchant, and the whole silver returned or accounfor. By mistake a one thousandth*was stated in the article Refining of Silver i n *Dictionary. _ , . gS

- RESINS. An ingenious memoir upon the resins of dammar, copal, and animo, 'lately been published by M. Guibourt, an eminent French pharmacien , from wlu c “following extracts may be found interesting. - ( j ie

The hard copal of India and Africa, especially Madagascar , is the product otHymenaa verrucosa; it is transparent and vitreous within, whatever may be its appance outside; nearly colorless, or of a tawny yellow.; without taste or smell Wcold, and almost as hard as amber, which it much resembles, but from which itdistinguished, 1st, by its smelting and kindling at a candle-flame, and running a0 '^; in 6,drops, while amber burns and swells up without flowing; 2dly, this hard copal or a jjjjewhen blown out and still hot, exhales a smell like balsam copaiva or capiv'i 0 f g3amber exhales an unpleasant bituminous odor; 3dly, when moistened by alcoho jj eper cent., copal becomes sticky, and shows after drying a glazed opaque surf ace , ^clamber is not affected by alcohol; 4thly, the copal affords no succenic acid, asdoes, on distillation. nsidct"

When the.pulverized copal is digested in cold alcohol of 0-830, it leaves a c0 jjohtl!”able residuum, at first pulverulent,' but which swells afterward, and forms a * “in-coherent mass. When this powder is treated with boiling alcohol, it assumes g n g er a.sistence of a thick gluten, like crumbs of bread, but which does not stick to the =>Thus treated, it affords, ._

Resin soluble in cold alcohol - - - - - ■

Resin dissolved in boiling alcohol ----- Jj-Resin insoluble in both - - - - - - -

100-83

The small excess is due to the adhesion of some of the menstruum to the resin