of Nitrification ; "joith an Extension of it. 179 



still the best work we possess upon the chemical manufac- 

 tures. 



" Having charged a retort with putrefying materials, Thou- 

 venel connected with it three receivers in the manner of Woulfe's 

 bottles, the last of which terminated in a tube communicating 

 with a pneumatic apparatus. Four different sets of this ap- 

 paratus were employed at the same time. In the first of these 

 the two receivers nearest the retort were charged with four 

 ounces of chalk diffused in distilled water, while the third re- 

 ceiver contained a solution of caustic potash. In the second 

 set the two first receivers contained distilled water, and the 

 last was charged with washed chalk. In the third set the two 

 first receivers contained lime-water : and in the fourth set a 

 solution of caustic potash ; the third receiver in both cases 

 holding the chalk. They were all equally exposed to the same 

 temperature, namely, from 74° to 80'' Fahr., for six months, 

 and the changes which their contents had undergone were then 

 examined. 



" The chalk in the first apparatus afforded 26 grains of 

 nitrate of lime mixed with a little nitrate of ammonia ; the 

 potash in the third receiver had become saturated with car- 

 bonic acid, and had partly crystallized on the side of the re- 

 ceiver, but contained no nitre. 



" In the second apparatus the water of the two first re- 

 ceivers had acquired a very putrid smell from the gas which 

 had passed through it, and contained a little ammonia, but 

 afforded no nitrous salt on evaporation : the chalk in the third 

 receiver afforded by lixiviation no more than 4 grains of ni- 

 trated lime. 



" In the third apparatus the lime-water had deposited its 

 earth in the state of carbonate, and the supernatant fluid had 

 a strong odour resembling ammonia and putrid garhc: by 

 evaporation it yielded 5 or 6 grains of nitrated ammonia. 

 The chalk in the third receiver gave only a slight trace of 

 nitrate of lime. 



" In the fourth apparatus the potash was crystallized, but 

 contained no nitre : with sulphuric acid it effervesced strongly, 

 giving out a very pungent and highly fetid gas : the chalk in 

 the third receiver gave no indications 'whatever of the presence of 

 any niti'ous salt. 



" The gas remaining in the receivers and collected in the 

 })neumatic apjjaratus, was in all the four experiments found to 

 be slightly inflammable, although when rising from the putre- 

 fying materials it extinguished a taper immersed in it. This 

 putrid inflanunable gas was incapable by itself of nitrifying 

 chalk ; but when mixed with washed atmospheric air, carbonic 

 2 A 2 ficid 



