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 tial loss of its efficacy. In dwellings of seve- 

 ral stories, it will be well to introduce the 

 dissolved or thinned substances, through the 

 opening in the conduit-pipe of the upper 

 story, so that the preservative may act upon 

 the matters remaining in the pipe, and by 

 the decomposition of which-, offensive vapors 

 would be generated. 



The efficacy of sulphate of iron, as a disin- 

 fectant of urine and faecal matters, has been 

 shown by Mallet in the following experi- 

 ment. 



On the 2d of October, 1844, he added to 

 the urine, of eighteen hours, at most, from 

 different individuals^ -^^th of a solution of sul- 

 phate of iron, making 27^ by Baume^s hydro- 

 meter, and left the mixture in a room of tem- 

 perature from 55'^ to 60° F. Upon the 11th 

 of December, the mixture emitted no odor, 

 whilst the same urine, alone and untreated, 

 under the same circumstances, exhaled in six 

 days an insupportable stench. 



The transformation of theureainto carbon- 

 ate of ammonia had taken place, for the mix- 

 ture, upon the addition of quick lime, in the 

 cold, gave a strong smell of ammonia. 



By reference to the proceedings of the 



