1 fS Exphjions in Giinpotvder ManufaBorles.' — Bleaching, 



more expreffive, would prefervc miich better the remembrance 

 of that illuftrious atrociation to which it has I'ucceeded, and 

 in whole l^^ps it propofes to tread. 



C. Lelchovin read a report on the difcovery of the phae- 

 nomenon of fcintillation by the coiiifion of charred wood. 

 Three fuccelin'e e.vpiolions took place in the courfe of four 

 nionlhs in tiie powder manufad ory of Vonges, notwithftand- 

 ing all the precautions employed to avoid them. The fre- 

 quent return of thefe events induced government to fend to 

 the fpot C. Lcm^itre, infpeftor- general, to inquire into the 

 caufe of thefe accidents. Having affured himfcif that no part 

 of the machinery was deranged, and that no foreign fub- 

 ftance had been introduced into the mortars, he endeavoured 

 to verity the fulpicions ciit'^rtained in regard to the employ- 

 nient ot charcoal in fticks. He recollecled, that under cer- 

 tain circumliances he had obtained fparks by the coiiifion of 

 charred wood : he therefore made a trial, and, after three or 

 four itrokes, excited three flrong fparks. This fa6l ferves to 

 account lor the cxplofions ; it explains why they do not hap- 

 pen more trequenily, and points out in what manner explo- 

 iions may be totally prevented, by adding one caution more 

 to thofe already employed, nanielv, to pulverize the char- 

 coal ufed in the nianufaclorv of gunpowder *. C. Lefchevin 

 terminates his memoir with the f llowing refleftion : — 

 *' Heat and light difengaged from a combullible body being 

 the more abundant as the combination of oxygen with the 

 body is ftronger in a given fpace of time, it feems to re- 

 fult from the diflerent circumllances of the phjenomenon I 

 have defcribed, that a very flight degree of heat only is re- 

 quired to cB'ecl the combination uf oxygen with charcoal, and 

 the combutlion of the latter." 



C. Potel, in a memoir on blenching, communicated to 

 the locicty intereding details rcfpccting the new method fub- 

 liituted lor the old one for bleaching linen, &c. He exa- 

 mined the (liHt'renl agents which have been recommended 

 for fome years poll ; gave an account of the refult of the ex- 

 periments he tried to afcertain the v;vlue of each of them ; 

 and coiiclr.ded his memoir by pointing out the moll: advan- 

 tageous ; fuch as odorous ou'grnated muriatic acid and 

 ciivjiic alkali hi vapour, which are thofe em])loyed in his 

 citabliflnnent. He fhowcd that the ufc of fulphurct of lime 

 without any mixture is ablblutelv improper for bleaching; 

 and how ill-founded is the fear of thofe who rejeil the new 



* 111 nH)lt of thi; gunpowdiT msriiif.ictorics in England, if not in all 

 of them, the pr;i(flicc', w.: htlicvc, Iihs long been to pulverize the charcoal 

 alone : yet cxplofions ibU take place, — Euii or. 



procds 



