Letter from R. R. Livingfion, to Arthur Youngs £/q. 147 



may make new names neceflary ; but change the v.ord 

 Phlogiflon to Caloric, Vitriohc to Sulphuric, &c. and the 

 theory will remain as it was, which in few words is this : 

 — That the alkaline vapours, or gazes, which float in the 

 atmofphere, attach themfelves to the fulphuric acid* of the 

 powdered gypfum, form neutral falts, which, being dilTolved, 

 enter into the compofition of plants : that the earth, deprived 

 of its acid, becomes cauftic, and is again reduced to a filenite, 

 by re-uniting with acids in the air (molt probably the nitric) 

 which is re-diflblved by alkalies, and the procefs, thus 

 continued till the calcarious earth is diflblved or walhed away, 

 or devoured in its attenuated flate by plants : That thefe falts, 

 in their folution, feize upon a certain portion of caloric in the 

 air, deflroy its elafticity, compel it to depofite the infinite 

 variety of matters that are borne upon or diflblved in it, and 

 perhaps decompound the air itfelf, and render it, or part of 

 it, food for plants. 



I have endeavoured, by this theory, to reconcile the various 

 phoenomena that gypfum exhibits, as you will find, by 

 recurring to the paper I refer to. But, after all, I confider 

 this as a mere fyfliem — and, like all other fyftems, to be 

 viewed as the fport of imagination, uniefs fo far as it fliall 

 appear to be confirmed by experiments. 



On thus opening a correfpondence with you, who are here. 

 Sir, confidered as the great parent of Britifli Agriculture, I 



