Black Ash-Mond's Process for Obtaining Sulphur.— giving a tolerably full account of Mond' process as described by himself, in using the waste fr°m the Black Ash generally employed in England, and which a rapid operation. than the more compact waste of most c°n- tinental works. In place of the set of four vats generaUy in use for lixiviating black-ash, he employs a set of ten ot twelve. a11 of thes “are connected by pipes in the usual way, so that the soda liquor runs from the bottom of one vat to the top of the next one, and by special pipes and taps which allow the sulphur liqUor to out of the bottom of each vat to the top of any other vat in the set. Besides this, they are provided With extra taps and shoots to convey the sulphur Hqura t0 weHs or settlers. ' The lower parts of aH Urn vats are conneCted with a fan (capable of producing a pressed of about seven inches o” water), by pipes furnished with dampras, which regulate the quantity of air passing through. A noiseless fan of Schiele's construction twenty mAra in diameter, price $50, propels a sufficien quantity of air for the treatment of the waste resulting fr°m 1°° tuns of salt cake per woek. Four of the vats are always filled with black-ash in the Cours!) of lixiviation ; the other six or eight with waste to be treated according to the inventbm As soon as the black-ash is completely spent, and the weak Uqu°r is wel1 drained qff, the connection with the fan is opened. The waste soon begins to heat, the t em perature gradUy rismg ab°ve <200° Fah., and gives off quantities of steam, tacornng greenish, and afterward yellow on top, gets mm-e and more dry, and would take fire if the air was passed thr°ugh long enough, The time for discontinuing the passing °f air, so as to have the best results, must be ascertained in each establishment by experiments, and varies according as much or little hyposulphite in the hydrosulphide and bisulphide of calcium are formed, which are afterwaM oxidized into hyposulphite, A part of the hyposulphite is again dwm- pOSed into sulphur and sulphite, which is very insoluble, and cann0t be extracted by lixiviation. Carrying the oxidation too far would therefore entail a serious loss. On an avera,ge the tone of exposu re will be limit ed to between twelve and twenty-four hours. The waste is now lixiviated sysrtenwti- cally with cold water, the weaker liquors passing fr°m °ne vat to the next one in course of lixiviation, so as to °bta,in only strong liquors, which operation can be easily perform m six to eight hours. When this lixiviatimi is fmished, air is again passed- through the waste in exactly the same way as before ; the waste is again lixiviated, and the sarnu treatment is repeated a third time. The vat is then ready to be cast, and is again filled with black-ash. Whm the °pera- tionS have been well conducted, sulphur equal to about 12 per cent of the weight of the salt cakes used in makmg blaCk-ask is obtained in solution from the waste. The waste contains only traces of sulphide of calcium, and is prinapadty composed of carbon ate of lime, s alphite, and sulphate of lime, which, far from being noxious, make the waste on the contrary, a valuable manure. In separating the sulphur from the liquors thus obtained, by adding muriatic ari I met with much more difficulty than I had anticipated from such a reaction. The oxidation of the waste is regulated so as to obtain a liquor, which contains as nearly as possible to every equl-ra- lent of hyposulphite two equivalents of sulphide. '{'his liqu°r is decomposed by first adding to a certain small quantity of acid an excess of liquor, until there is a trace of sulphide m the mixture ; then a quantity of acid sufficient to neutralize the whole of the calcium is poured in ; a new quantity of liquor equivaleut to this last quantity of acid is added, and then acid again and liquor again, and so on until the vessel is nearly filled. To the last liquor only one half of the required acid is added, and steam, introduced Until the liquid shows a temperatu re of about 140° Fah. Practically speaking, the liquor and acid are poured at the same time into the decomposing vessel in nearly equivalent proportions, the workmen taking care to keep a small excess of liquor up to the end of the operation. This part of the process is carried on in covered wooden tanks connected with a chimney in order to carry off any sulphureted hydrogen which may be evolved by mistake of the workmen. If properly carried out there should be, however, no appreciable quantity of that gas evolved. The practical result of this mode of working is simply precipitation of nearly the whole of the sulphur in a pure state. Ca 0, S2 O2 + Ca Sx + 3 H Cl=3 Ca Cl + 3 H 0 + (2 + x) S. The details of the reaction are, however, very complicated, almost all the different acids of sulphur bein g probably formed during the process. > IE. practice, about 90 per cent of the muriatic acid, calcu- lated according to the above-deseribed method, is re quired to thus effect the complete decomposition of a well-proportioned liquor. If it contains more hydro sulphite than above indicated, less aeid is, of course, to 1)e used. About 90 per cent of the sulphur contained in the liquor is precipitated in an almost pure state, and settles exceedingly well within two hours. The supernatant clear solution of chloride of calcium is then drawn off, and another operation directly commenced in the same vessel as soon as a sufficient quantity of sul phur is collected in it, which will depend on the size of the vessel and on the strength of the liquor, ranging from 4 per cent to 7 per cent of sulphur; it is drawn out by means of a door at the lower part of the vessel into a wooden tank with a double floor, where the chloride of calcium is washed out by water, and the sulphur is then simply melted down in an iron pot. The product thus obtained contains only from one tenth of one per cent to one per cent of imp urities, and is thus by far superior to any sort of brimstone in the market, though it has sometimes a rather darker color, caused by traces of sulphide of iron, or a little coal dust, which latter may have been suspended in the muriatic acid. The total yield of sulphur obtained by the process amounts thus to 10 or 11 per cent of the weight of the salt cake used in maims black-ash, or to about one half of the sulphur therein contained, and to about 60 per cent of the sulphur contained in the waste. It is still hoped, however, to considerably increase this quantity after some more years of experience. The cost of production is inconsiderable. , In the different continental and English works, where the process has now been working for years, the expense for wages, tuel, and maintenance amounts only to $-5 per tun of sulphur, and the outlay for the apparatus will be more than covered by the net profits of the first year. An establishment making three tuns can save at least $2,000. (To be continued.)