and Peat-charcoal for Agricultural purposes. 175 



ing some diluted sulphuric acid of known strength over each 

 mixture, finally covered the whole with a bell-glass ; the mercury 

 serving to exclude the air. Having left the mixtures thus covered 

 for five days, I removed the bell-glasses and examined, by Peli- 

 got's method, the acid contained in each evaporating dish. I 

 could not detect any ammonia in that placed over the peat, show- 

 ing that none had been evolved, and that the peat had completely 

 retained and fixed, as it were, the volatile carbonate of ammonia 

 existing in the urine. On the other hand, in the case of the 

 peat- charcoal, the acid indicated the absorption of 0*288 part of 

 a grain of ammonia, or considerably more than one-fifth of the 

 entire quantity existing in the urine of the mixture which had 

 been evolved. 



I repeated this last experiment, mixing 500 grains of peat and 

 of peat-charcoal with 1 fluid ounce of the same ammoniacal 

 urine, and employing a similar arrangement as in the last, with 

 the exception of using diluted muriatic instead of sulphuric acid 

 for absorbing the evolved ammonia. After the mixtures had 

 been left for sixteen days, I removed the bell-glasses, and found 

 that the mixture with peat-charcoal had a slight urinous smell, 

 and was still evolving ammonia, which was apparent both 

 by its odour and its action on tiu-meric paper suspended over 

 the mixture ; whereas the mixture with peat had no smell what- 

 ever, and no evolution of ammonia could be detected by means 

 of turmeric paper. On evaporating to dryness in a water-bath 

 the two acids placed over each mixture, I obtained in the case of 

 the peat-charcoal a residue of 5-7 grains of muriate of ammonia, 

 which is equivalent to 1"812 grain of ammonia, or just about 

 three-fourths of the entire ammonia contained in the urine em- 

 ployed which had been evolved and afterwards absorbed by the 

 acid. On the other hand, in the case of the peat there was an 

 inappreciable residue, which on being dissolved in a little water 

 and treated with caustic lime, gave a slight indication of ammonia, 

 showing that only a very minute quantity had been evolved; 

 and this may in part be accounted for by the peat being mixed 

 with a larger proportion of urine in this than in either of the two 

 former experiments. 



The loss of ammonia in the case of the peat-charcoal in these 

 two latter comparative experiments is not so great in proportion, 

 considering the time occupied, as in that of the foi'mer ; but this 

 is easily explained by the surface exposed not being so large, 

 and the experiments being made under bell-glasses, the same 

 facilities for the evolution of ammonia were not present as when 

 the mixture was exposed to the open air ; but had the experi- 

 ments been carried on longer, a much greater loss of ammonia 

 would have taken place ; for on opening the bell-glasses in each, 



