J2(> INJURIOUS MANUFACTORIES. 



that the emanations from them appear to be fo much the' Iefs 

 dangerous, as the fubftances which undergo putrefaction are Iefs 

 humid: in the latter cafe, aconfiderable quantity of carbonate 

 of ammonia is evolved, which imparts its predominant charac- 

 ter to the other matters volatilifed, and corrects the bad effects 

 of fucli as are deleterious. Thus the decomposition of fter- 

 coraceous matters in the open air, and in places the (ituation 

 * and declivity of which allow the fluids to drain off, and that 



of the refute of the cocoons of the filk-worm evolve a vaft 

 quantity of carbonate of ammonia, which corrects the virus 

 of fome other emanations; while the very fame fubftances, 

 decompofed in water or drenched with this fluid, exhale fweet- 

 i ifli and naufeous miafmata, the refpiration of which is very 



dangerous. 



->d clafs. The numerous arts in which the manufacturer produces and 



diffufes in the air, in confequence of his procefies and by the 

 help of fire, vapours more or lefs difagreeable to breathe, con- 

 ftilute the fecond clafs of thofe we have to examine. 



Thele, more interefting than the former, and much more 

 intimately connected with the profperity of our national in- 

 dustry, areftill oftener the fubject of complaints brought be- 

 fore the magistrate for decifion, and on this account have ap- 

 peared to us to require more particular attention. 



We will begin our examination with the manufacture of 

 acids. 



jltffo. The acids that may excite complaints of the neighbours 



againft their preparation are the fulphuric, nitric, muriatic and 



acetous. 



„ , , . .. The fulphuric acid is obtained by the combuftion of a mix- 



bulphuriC acid* * J 



ture of fulphur and nitre. It is very difficult in this procefs to 



prevent a more or Iefs obfervable fmell of fulphurous acid 

 from being diffufed around the apparatus, in which the com- 

 buftion is performed; but in manufactories (kilfully conducted 

 this fmell is fcarcely perceptible within the building itfelf, is 

 not dangerous to trie workmen who refpire it daily, and can 

 give no reafonable foundation for complaint to the neighbours. 

 When the art of making fulphuric acid was introduced into 

 France, the public opinion was ftrongly expreffed againlt the 

 fiift eftablifhments for the purpofe; the fmell of the match 

 with which we kindle our fires contributed not a little to ex- 

 aggerate the effect that mult be produced by the rapid com- 



2 bullion 



