and Peat-charcoal for A gricultwal purposes. 173 



&c., possess considei'able deodorizing properties, and may in cei'- 

 taiu cases be usefully employed for sanitary purposes, but are 

 quite unfit to be used in making manures from animal excreta, 

 because they either decompose some of the most valuable con- 

 stituents of those matters, or are injurious to vegetation. 



The most important substances which have yet been proposed, 

 both for deodorizing and the manufacture of manui'cs from pu- 

 trescent matters, are peat and peat-charcoal. 



The deodorizing property of vegetable charcoal, from whatever 

 source, has long been known ; that of uncharrcd peat was first 

 clearly ascertained by my father. Professor Davy, who at the 

 scientific meetings and lectures of the Royal Dublin Society, and 

 subsequently in a pamphlet, called public attention to it; and 

 his statements have since received the most ample confirmation 

 from various som'ces. Peat, therefore, in its charred or un- 

 charred state, may be used as a deodorizer for sanitary purposes, 

 and it becomes little more than a question of expense which 

 should be employed for this object. 



A difference of opinion, however, is entertained whether peat 

 or peat-charcoal is the best adapted to deodorize animal excreta, 

 &c., where the object is to manufacture manures. The advocates 

 for the use of peat-charcoal allege, as one of the most important 

 of its properties, that, when mixed with decomposing animal 

 excreta, it absorbs and retains the ammonia which is evolved 

 from such matter. If peat-charcoal really does this, it effects a 

 valuable object, as the importance of ammonia as a food of plants 

 and a fertilizer of the soil is well established. 



With a view to throw some light on this subject, if possible, I 

 made some comparative experiments with peat and peat-charcoal 

 on stale lu'ine, which by decomposition had become highly am- 

 moniacal. This urine was put into a well- stoppered bottle and 

 kept for the experiments. As peat from different localities differ 

 in certain respects, I employed the same sods, charring one part 

 of each, and leaving the other part uncharred. The peat on 

 being converted into charcoal in a close crucible, was, on cooling, 

 immediately put into a dry bottle and kept well corked. The 

 uncharred peat was broken into pieces and placed in a similar 

 bottle, and both on being used were reduced to the state of 

 coarse powder, the particles of each being about the same size. 

 Having taken equal weights of the powdered peat and peat- 

 charcoal, I put them into two similar evaporating dishes, and 

 intimately mixing each with the same quantity of the annno- 

 niacal urine, left the mixtures exposed to the air for some days 

 under an open shed where they were protected from the rain. 

 The proportions I employed were 500 grains of peat or peat- 

 charcoal to 6 drachms by measure (or about 355 grains by 



