March 2, 1855.] Dr, Stenhouse on Charcoal, 53 



WEEKLY EVENING MEETING, 



Friday, March 2. 



William Robert Grove, Esq. Q.C. F.R.S. Vice-President, 

 in the Chair. 



Dr. John Stenhouse, F.R.S. 

 On tlie economical applications of Charcoal to Sanitary purposes. 



After describing the various ways in which both animal and 

 vegetable charcoal are manufactured, Dr. Stenhouse stated, that the 

 different kinds of charcoal most commonly in use may be con- 

 veniently divided into three species, viz. wood, peat, and animal 

 charcoal. The results of Saussure's experiments on the absorption 

 of gases by boxwood charcoal were then exhibited in a tabular 

 form. The speaker then described a series of experiments made 

 by him to ascertain the comparative absorbent power of wood, peat, 

 and animal charcoal for gaseous bodies. From these it appeared, 

 that wood charcoal possesses a slightly higher absorbent power for 

 ammoniacal, sulphuretted hydrogen, sulphurous acid, and carbonic 

 acid gases than peat charcoal ; the absorbent powers of which, 

 however, are immensely greater than those of animal charcoal. 

 As a decolorizer, however, animal charcoal is greatly superior to 

 either wood or peat charcoal. 



An account was next given of Mr. Turnbull's and Dr. Stenhouse's 

 experiments, which consisted in burying the bodies of dogs and cats 

 in charcoal powder, and in covering them over with about a couple 

 of inches of the same material. No effluvia were ever perceptible, 

 while the decomposition of the bodies was greatly accelerated. 

 This arises from the circumstance that charcoal absorbs and oxidises 

 the effluvia, which would under ordinary circumstances be evolved 

 directly into the air ; but within the pores of the charcoal they are 

 brought into contact with condensed oxygen, and are thus subjected 

 to a species of low combustion, their carbon being converted into 

 carbonic acid, and their hydrogen into water. Charcoal, therefore, 

 so far from being an antiseptic, as was till recently universally 

 believed, is, in fact, precisely the reverse. 



Dr. Stenhouse then stated that, from reflecting on the wonderful 

 power of charcoal in absorbing effluvia and miasmata, as exhibited 

 in the cases just described, where, as we have seen, all the putrid 

 exhalations from the bodies of pretty large animals were absorbed 

 and destroyed by a layer of charcoal powder little more than an 

 inch in thickness, it struck him that a very thin layer of powdered 



