554) Summary View of the Progress of Gardening, 



does not amount to one four thousandth part of the weight of the charcoal ; 

 hence it burns with as much facility as the charcoals of other light woods. 



" It is therefore quite evident, that this charcoal must diffuse in the apart- 

 ment as much carbonic acid during its combustion, as an equal weight of any 

 other charcoal, that it must vitiate the air in the same degree, and that the 

 same accidents may be produced by it as in other cases ; it is equally evident, 

 that it can produce no more heat than the same quantity of common charcoal, 

 as it contains no more combustible matter." 



M. Gay-Lussac, having ascertained that the combustion of 

 this charcoal produced no unpleasant odour, next tried some 

 experiments to discover the cause of this, and he found it to be, 

 that it was prepared from fir-wood. He therefore prepared some 

 charcoal from pieces of deal ; and the result was a very light, and 

 sensibly more alkaline, charcoal, than that employed in Joyce's 

 stove. The economy of Joyce's apparatus, M. Gay-Lussac 

 observes, cannot be disputed; since it diffuses all the products 

 of combustion throughout the apartment in which the stove is 

 placed : but he adds that this economy is gained at the expense 

 of vitiating the air of the apartment. 



Soon after the publication of M. Gay-Lussac's report, the sub- 

 ject was brought before the Westminster Medical Society, by Pro- 

 fessor Everett, whose analysis agrees in every respect with that 

 of M. Gay-Lussac. He also states that he discovered the pre- 

 pared fuel "to be only well-burnt wood charcoal, with, perhaps, 

 a little additional alkaline carbonate; not containing, as common 

 charcoal often does, portions of wood half-charred, which, when 

 the charcoal is lighted, give off some smoke and certain vapours 

 irritating to the eyes and nose ; but, as respects the quantity of 

 carbonic acid and heat produced during the burning of a given 

 weight of this, and the same weight of well-prepared charcoal, 

 there is no appreciable difference." [Mech. Mag.., vol. xxix. 



About the same time Joyce's stove was exhibited at a meeting of 

 the Royal Society of Edinburgh ; when, in order to place the dele- 

 terious effects of the fuel beyond all doubt, Sir John Robison, one 

 of the secretaries, held a lighted taper above the orifice whence 

 the products of combustion escaped, when, notwithstanding the 

 absence of smell from the vapour, and its being quite clear and 

 tasteless, the taper was speedily extinguished. 



It is slated in the Mechanic's Magazine, on the authority of 

 Mr. Everett, that, "as soon as Mr. Harper, Mr. Joyce's partner, 

 was acquainted with the positive results arrived at by Mr. Everett's 

 investigation, he expressed his determination to attach to all 

 stoves which he should in future sell, contrivances for carrying 

 out of the apartment all the products of combustion; and that 

 Mr. Everett produced a box, or stove, where this was already 

 effected. He farther begged to say that Mr. Harper expressed 

 his readiness to adopt any suggestions which might tend to avoid 



