March 1, 1805.] T11H TECHNOLOGIST. 



ON CHEMISTRY APPLIED TO THE ARTS. 351 



Consequently the absorption or condensation of a gas in charcoal appears 

 to be in proportion to the solubility of the gas in water, and although 

 the condensation by a solid and by a liquid may at first appear neces- 

 sarily due to different causes, and therefore to bear no relation to each 

 other, yet in my opinion these two actions are identical. Seeing that 

 the gas is condensed by the molecular attraction of the solid, I do nut 

 see why the same attraction should not be exercised by the molecules of 

 the liquid. The different degrees of solubility of various gases are no 

 doubt owing to their respective physical properties, such as specific 

 gravity, repulsive or expansive forces of their molecules, &c. I may 

 here mention that I am now engaged in a series of experiments in the 

 hope of throwing some light on this interesting question. 



Gay-Lussac, in his researches on the condensation of gases by char- 

 coal, found that one gas may expel and take the place of another gas 

 already condensed in the charcoal ; and Dr. Stenhouse, following up 

 this observation, states that the gases, vapours, and sporules generated 

 by the putrefaction of animal substances, are absorbed by charcoal and 

 brought into immediate contact with the oxygen of the atmosphere also 

 contained in the pores of the charcoal, which oxidising or destroying 

 the products of putrefaction converts them into water, carbonic acid, 

 nitric acid, &c. These important scientific observations of Dr. Sten- 

 house have already received practical application ; thus Mr. Haywood 

 has established charcoal filters at the mouths of public drains, thereby 

 arresting the escape and diffusion in the atmosphere of the noxious 

 effluvia given off by the putrefying matters in the sewers. Further, 

 charcoal respirators have become extensively used since Dr. Stenhouse 

 called public attention to the valuable properties of this substance ; and 

 lastly, atmospheric filters, containing charcoal, have been successfully 

 applied in the Houses of Parliament to purify the entering air from any 

 noxious gases it may contain before passing into the building. The 

 natural decay or destruction of organic matters is due to two perfectly 

 distinct causes, one of them chemical and the other physiological. The 

 former has been investigated by many of the most eminent chemists of 

 the day, and no d<jubt can remain that the action of the oxyge'n of the 

 atmosphere converts the carbon of organic substances into carbonic 

 acid, the hydrogen into water, the sulphur into sulphuric acid, the 

 nitrogen into nitric acid, the phosphorus into phosphoric acid, &c. 

 Much light has recently been thrown upon these phenomena by Mr. 

 Kuhlmann, who clearly shows that the oxides of iron play a most impor- 

 tant part therein ; thus, that the sesquioxide of iron yields its oxygen 

 to the elements of the organic matters ; that the protoxide of iron there- 

 by formed absorbs oxygen from the air, which reconverts it into sesqui- 

 oxide, and this again yields its oxygen to a fresh portion of organic 

 matter, so that sesquioxide of iron is a most powerful oxidising agent, 

 it being, in fact, the condenser of oxygen and the medium of its con- 

 veyance to and destruction of organic substances. MM. Chevreul and 

 vol. v. Q Q 



