BON 



BON" 



fhcreanng, bone yields, at firft, a limpid water,. with a pecu- 

 liar animal oily fmell, which foon becomes ioiiiregnated With 

 carbuuated an:)mo:iia, togtthcr with an oil, at firll of a clear 

 yellort'j pungent, and nut ungrateful to the fmtll, but after- 

 vrards rendered brown, and even black, by the increafing 

 heat, ftrongly fetid and ammoniacai. With the eirpyreu- 

 matic oil, a large quantity of fulphuratcd hyGroj.rtn, of 

 carbonated hydrogen, and of carbo;:ic acid gas efcapes. 

 The produft;, of this diftillation, when condeiiled, are the 

 ammoniacai water, and the tmpyreumatic oi! ; the former 

 contains, befides carbonaL of ammonia, a portion of febacic 

 and pruffic acid united with the alliali ; the oil may- 

 be feparated ii;to the lefs and more tmpyrenmatic, by 

 changing the receiver occafionally, and keeping apart the 

 firil portions of the oil as the pureft. If this oil is again 

 repeatedly diftiiled by itfelf from clean vefTels with gentle 

 &eat, it becomes at lalt as colourlefs as water, pun- 

 gent, and not very unplcafant to the fmell, fo volatile at a 

 common temperature as only to be kept by inverting under 

 water the months of the vefTels that contain it, and aftingin 

 medicine as a powerful fndorific. It is called from the name 

 of the inventor, Dippel'j- oil, which fee. 



The only valuable part of the produfts of the diftillation 

 of bone is the ammonia, or volatile alkali, which is mixed with 

 €V;.-ry part of the di billed liquid, and is afterwards purified 

 by fubfequent proceflcs, affilling in the formation of the 

 MuRiAT of ammonia, or forming the pure Carbonat of 

 emiiionia of the fhops, \.he ful "volatile, fp'irit of hartjlmrn, &c. 

 When the diftillation is difcontinued, the bones remain in the 

 retort of a brown colour, and fwimming in a black, thick, 

 extremely fetid, tenacious oil. If they are then gradually 

 heated to rednefs in clofe iron vefTels, every thing volatile is 

 diflipated, and the earthy part remains dry and friable, ftill 

 retaining the original form of the bones, but thoroughly im- 

 'pregnated with the charcoal of the oil, foas to become a fine 

 gloily black. This is afterwards ground to a fine powder, 

 mixed with lize into cakes of a convenient weight, and forms 

 one of the fpecies of lamp-black, ufed very largely as a pig- 

 ment. The harder and compafter bones, fuch as ivory, fur- 

 nifh a fimilar and more -valuable black pigment, fimply by 

 heating to rednels in clofe vefTels. 



But tlieanalyfis by heat, though it furnifhes feme valuable 

 articles of commerce, is not well calculated to exhibit the con- 

 ftituent p:'rts of bone in their proper chara(9:ers. 



In fact, the ammor.ia, probably mucli of the oil, and all 

 the gafTes, are formed by the aftion of heat out of the real 

 conitituents of bone, as they exift in the animal. 



Water and acids are the chief re-agents to be ufed by the 

 chemift. 



Cold water has fcarcely any aftion on bone, but by long 

 maceration its texture becomes more loofe and open, and the 

 gelatinous part becomes gradually changed, as by flow animal 

 putrefaftion. 



Hot water afts with great eafe upon bone, when reduced 

 to fmall pieces by rafping or bruifing ; the firl): efTeft is to 

 leparate molt ot the naiural oil of bone which rifes to the 

 top, and when cool concretes to a fuety fat. The water 

 then difTolves the gelatin, which is found to compofe a very 

 confiderable part of the fubllance, even of the dritfl and mofl 

 compail bone ; and in this method a clear infipid pure jelly 

 if extracted, rendering the water, even when in large propor- 

 tion, of a ftiff, tremulous confillence when cooled, which, 

 by evaporation, leaves at lalt a flrong, hard^/i/i-. 



The experiments of M. Pelletier on this fubjeft are im- 

 portant. This accurate practical chemill took fix pounds of 

 dry bone fhavings, procured from the button-mould makers, 

 macerated them for two days in cold water, and then boiled 

 them for nine hours with 24 quarts of water. The produft 



was a very flrong clesr jelly, and at the bottom of the vcfTel 

 the marc, or earthy rtfidue, which was prcfled in order to- fc- 

 p^rate thv portion of fomewhat turbid jolly, with which it was 

 entangled. By fubfeqnc.it boi'ing down, the jelly became 

 fo ftifTwhen cold, as to bear to be cut into firm fikcs, which 

 were hung up on firings in a place under cover from the 

 weather (as in the common manufaclure tif glue), and in a 

 fortnight became hard, brittle glue of good quality. The 

 produce was 15! ounces of clear glue, l.a'.l ;:n our.ce more 

 from the marc, and fomewhat foul, and the marc itfelf 

 weighed 41b. 3 oz. The lofs in the operation amounted to 

 13 oz. In like manner 50 lb. of ivory ihavings, exhauilcd by 

 repeated boiling, gave 95 lb. of clear glue, and 30 lb, of the 

 marc remained. 



Thefe fafls are impo-tant to the manufacturer ; nor is the 

 ufeof bone L-fs intercfting as an article capable of fupplying 

 iriuch good and wholefome nutriment to man and ether ani- 

 mals: In the rr; king of foups it is a matter of con^mon ob- 

 fervation, that bones contribute, when boiled with the meat, 

 to the richnefs of the liquor ; but it is not commcnlv known 

 how much they may be made to add to the nutritious qua- 

 lity ; nor is it generally known that the hardefl and dricft 

 bones, even thole that have been kept for years, retain their 

 gelatinous part unchanged. 



The exaft proportiorr of jelly cannot eafily be afcertaincd 

 by extraftion with water, for even when converted into the 

 hardeft glue, it has become intimately united with a portion 

 of this fluid ; and it is by no means certain that the utmoft 

 deficcation of glue equals the degree of drj'neis of natural 

 gelatin, as it exifts in the more folid bones. 



The quantity of jelly is alfo much increafed, either by 

 giving the water by which it is extrafted a higher heat than 

 the boiling point, or by reducing the bones to a fine powder, 

 and ufing repeated codtion and pulverization. 



The former method was ufed by Papin, who, in his va- 

 luable experiments on the folubility of animal fubllances, 

 when confined with highly heated water in his Di^fjhr, 

 found that he was able to extradl every thir.g from powaer-ed 

 bone, but the mere earthy part. The latter mode has been 

 bro'ight into notice by M. Proult, in an impcrtant econo- 

 mico-chemic^l memoir on the " Method of amiiiorating the 

 fubfiftence of the Soldier," publifhed at Madrid, in 1791. 



Though there is a great i;eneral fimilarity betweeo the 

 bones taken from different parts of the body, they differ 

 much in the relative portion of fat, of gelatin, and of earth. 

 The younger the animal is, the lefs earthy fait, ceteris pari- 

 bus, is contained in its bones. The large, round, joint- 

 heads of the thigh, and other lar-ge bones, contain much 

 more oil than the rib or blade bones, as is feen when they 

 are expofed to the air ; the latter foorr becoming dry and 

 clean, but the former remaining long foul ard greafy. 



No method of extradling all the foluble part of bone 

 anfwers the purpofe fo completely, as longboihng in Papia'j 

 digeller with a very great heat ; the earthy rcfidue tlien re- 

 mains quite friable in the fingers, and gives little, if anv, 

 volatile, oily, or ammoniacai produtl on burning. But the 

 jelly which remains iir the water, arrd the oil which fwim.s 

 at the top, are found to have acquired a biirat unplcafant 

 tafte ; and in the proctfs, a confiderable quantity of gas is 

 generated, doubttefs fi-om partial decompofition of the fo- 

 luble par-t. On the other hand, even after repeated boiling 

 and laboi-ious pulverization, unafTifted by a higher heal than 

 that of boiling water, the earthy refidue ftill feclb clammy and 

 cohefive between the finger?, and retains fome of the oil. 



M. Prouft afTerts, that the knuckle and joint bones fim- 

 ply chopped into fmail pieces, and boikd for a quarter of 

 an hour in a common copper, yielded no lefs than one fourth 

 of their weight of fine infipid fat, which rofe to the top of 



I the 



