BONE-BLACK. 



63 



the coal is rcburncd as before, and returned 

 to tlio filters. Such a method being properly 

 carried out, there is no necessity of throwing 

 aside the charcoal after a stated period; but its 

 use is continued until, being gradually removed 

 in form of fine waste, it must be replaced by 

 lew. 



'</// and Cuisinier^s Process, with Steam, 

 ami A Jkaline and Acid Solutions. The authors 

 named presented before the Academy of Sci- 

 ences, Paris, on the 10th of February, 1862, a 

 new theory of, and process for, the revivifica- 

 tion of bone-black. They had found that the 

 common supposition, to the effect that the black 

 loses and again has restored within it, at the 

 same time, its absorptive powers for all the dif- 

 ferent sorts of impurities, is erroneous; that 

 such powers are not simultaneously exhausted ; 

 that, when exhausted, they can be revived in 

 succession, and require different means; and 

 that, in the process of reviving, the total ab- 

 sorbing power of the black can be increased. 



Thus, the authors state that the absorption 

 for the viscid, azotized, ammoniacal, sapid, and 

 odorous matters in a saccharine solution is ex- 

 hausted in about four hours' time [referring evi- 

 dently to the case of beet juice and syrups, in 

 which such matters abound], and is to be re- 

 stored by passing a blast of steam through the 

 charcoal in the filter, as may be done an in- 

 definite number of times ; that the absorption 

 for free alkalies, lime, and salts, is exhausted in 

 from 24 to 82 hours, and is to be restored by 

 pouring on the charcoal in the filter a weak so- 

 lution of chlorhydric acid, and afterward wash- 

 ing thoroughly with water ; that, if the black 

 were not sooner revivified, the absorption for 

 coloring matters would be lost in a period from 

 80 to 40 times as long as the first a power, to 

 aid in restoring which, a weak boiling solution 

 of a caustic alkali [or of its carbonate, as of soda] 

 is to be applied. All the operations indicated 

 can be performed on the charcoal directly as it 

 stands in the filters ; or, if it be removed from 

 them, in similar receptacles. Finding, more- 

 over, that the dibasic phosphate of lime (2 CaO, 

 IIO. PO 6 ), while it is mainly insoluble in wa- 

 ter, possesses a much higher absorbing power 

 for the impurities in syrups than does the tri- 

 lasic phosphate (3 CaO. P0 6 ) naturally present 

 in the bone, the authors complete their process 

 by pouring upon the charcoal in the filters a 

 dilute solution of the monobasic phosphate of 

 the same base (CaO, 2IIO. P0 6 , known also as 

 the " biphosphato ") : by reaction of the two 

 salts thus commingled, some libasic phosphate 

 results in the coal ; and, though the addition 

 may in part have in view the restoring of ab- 

 sorbent power lost through the previous action 

 of chlorhydric acid on the bone, yet it is stated 

 that, as the actual result, the decolorizing and 

 purifying powers of the latter are made even 

 greater than when it was fresh, and than after 

 any mode of merely reburning. 



MM. Leplay and Cuisinicr have also em- 

 ploye i the tribasic phosphate of lime for pre- 



cipitating the matters rendering syrups, etc., 

 turbid, and that more completely than ', 

 fected with blood. The specification-; lor their 

 ynited States patent (of the year already named) 

 cover the use, separately or in succession as may 

 be required, of steam, of solution of carbonate 

 of soda, of dilute chlorhydric acid, and of tli<- 

 monobasic phosphate of lime ; clarification with 

 phosphates ; and the collecting of the ammoni- 

 acal gases expelled from bone-black during re- 

 vivification, thus incidentally also obviating 

 their escape into the atmosphere. 



Prof. Calvert's statement of the practical ap- 

 plication of this method is briefly as follows: 

 After escape of all the syrup from the filters, 

 the black is washed through in them with hot 

 water, and the viscid, ammoniacal, saline, and 

 coloring matters are then removed, and some 

 of them in successive parts, by 1, throwing in 

 steam from below ; 2, washing through with 

 alkali, in a weak solution ; 3, washing with a 

 weak solution of chlorhydric acid, to dissolve 

 out lime ; 4, completing the removal of coloring 

 matters, by washing again with alkali ; and 5, 

 adding solution of biphosphate of lime, to in- 

 crease the absorbent powers of the coal. So 

 far as objection has been raised against this 

 process on the ground that its application is 

 tedious, the same objection would appear more 

 or less to hold against all revivifying processes 

 which are in the highest degree effectual. And 

 whether the process itself prove practicable or 

 not, yet the highly original results at which 

 the authors named have arrived will still pos- 

 sess much theoretical value. Their influence, 

 indeed, appears to be already shown in the 

 character of the more recently devised pro- 

 cesses, as in that of Mr. Beanes, who would 

 seem to have used, and in some respects im- 

 proved on, certain of the ideas of MM. Leplay 

 and Cuisinier. 



Beane *' Process with Chlorhydric Acid Gas. 

 The statements of Mr. Medlock, already cited be- 

 cause of their general application, were made 

 in connection with his account of the revivi- 

 fying process of Mr. Edward Beanes, of Kil- 

 burn, England, now to be considered. The 

 object aimed at by the latter was that of de- 

 vising a plan by which the absorbed lime and 

 carbonate of lime may be removed from the 

 contents of the filters, without attacking the 

 lime-salt of the bone. 



In Mr. Beanes's original process, the bone- 

 black, removed from the cylinders, dried and 

 rendered quite hot, is then treated by throwing 

 through tho mass a current of perfectly dry 

 chlorhydric acid gas: this is apparently ab- 

 sorbed, and in enormous quantities, reacting in 

 reality with the previously absorbed lime in 

 the black to form chloride of calcium, which is 

 highly soluble; while, as stated, the phosphate 

 of the bone is not attacked. Subsequently, a 

 portion of untreated black is mixed with that 

 so purified, the former serving to neutralize 

 any still uncombined acid ; and, the chloride of 

 calcium being washed out, as is done u> a fa** 



