400 Necessity and Advantage of Scientific Enquiry 



ceeded in clearly explaining such principle. But, although the 

 chenaists have not made us acquainted with any better means 

 of supplying the necessary quantity of carbon, than that of 

 collecting and accumulating animal and vegetable matters, and 

 leaving them to be reduced by the processes of nature; nor of 

 the principle required to make carbon available as food for 

 plants ; they have taught us, that, by availing ourselves of 

 the knowledge of the affinity of one substance for another, we 

 may so control and direct the decomposition, as not only to 

 hasten it, and prevent the loss of carbon by its combination 

 with the gases, but, by observing the effect of certain combin- 

 ations, we may exert such an influence as will convert decom- 

 posed vegetable and animal matters, from an inert, into an active 

 and available state ; and thus, perhaps, lead to the discovery of 

 the principle or element required to be combined with carbon 

 to render it effective. 



It is known, that when animal and vegetable substances are 

 deprived of life, and left to nature, a spontaneous decomposi- 

 tion takes place, by what is called fermentation ; and it appears, 

 that, during the process of the putrefactive fermentation, carbon 

 is liberated in the greatest quantity, and reduced to a state 

 that is best appropriated as food for plants ; and that, at the 

 same time, a part of the carbon, which is liberated by this pro- 

 cess, unites to oxygen, and forms carbonic acid gas ; and a 

 part also unites with hydrogen, and forms carburetted hydro- 

 gen gas ; and, when in this state, the carbon is dissipated and 

 lost to the plants. To prevent this loss, and, as they say, at 

 the same time to facilitate putrefaction, the chemists recommend 

 the addition of quicklime to the fermenting mass ; but in this, 

 I conceive, they are under a mistake ; for, the formation of car- 

 buretted hydrogen gas being an inevitable consequence of 

 putrefaction, any substance that will prevent such formation 

 must be considered as obstructing the putrefactive ferment- 

 ation. Quicklime, added to a fermenting substance, will no 

 doubt hasten its dissolution, and at the same time prevent the 

 formation of carbonic acid gas, but such a decomposition can- 

 not be synonymous with putrefaction. And further, although 

 quicklime will hasten the decomposition of animal and vege- 

 table matter and retain the carbon, it will, at the same time, 

 form other compounds, which are not soluble in water, and, 

 therefore, although it prevents one loss, it will occasion an- 

 other, and a greater. But, if lime be slaked before it be added 

 to the fermenting matters, it will equally facilitate its decom- 

 position, and form other compositions that will be perfectly 

 soluble. Yet, however powerful, as an agent in vegetation, 

 lime may be ; and there can be no doubt, that when properly 



