128 Mrs. Ibbetson on the Action of Lime [Aug. 



of wood, or whether it can be done with a complete carbonate 

 of lime divested of all heat, the next trial must decide, as the 

 lime has been rendered and reduced to a thorough carbonate. 

 If, therefore, it decomposes the plants now, it must be by the 

 power of the mild lime alone, and not in consequence of its 

 passage from quick lime to mild lime, as Sir H. Davy conceived, 

 and as it was most natural to suppose. 



Dec. 8.— This letter was to have gone to the editor of the 

 Annals of Philosophy, but has been so long delayed, I shall add 

 the conclusion of the experiment, having now taken up my next 

 trough, which has completely verified my first trial, that though 

 animal manure will be perfectly protected from decay by the lime 

 surrounding it, yet it will thoroughly decompose vegetables, nor 

 coagulate around them, though ever so much lime may be added 

 to the trial. There is certainly in the carbonate of lime a power 

 of decomposing vegetables and reducing them to that state in 

 which they can again arrange their various ingredients, so that 

 each may adapt itself to forming new combinations, becoming 

 new matter for the food of plants, since we have traced it to a 

 black powder, and then to a sort of brown liquid. 



I also put in some plants, half earth and half lime, on vege- 

 table matter, to see what effect so contradictory a trial would 

 produce, but it had not yet remained long enough to obtain the 

 result. 



But the former experiments show the necessity of turning in 

 much lime into bog soil, since there is no danger of its plaster- 

 ing the vegetable as it does the animal matters, and coagulating 

 around them, which would at once render them inert. But as it 

 acts not thus, too much can hardly be given when large portions 

 of roots and hard wood are to be decomposed, which is generally 

 the case in almost every dark-brown bog. Rich soils require 

 not so much, as it would rather injure these ; it is merely the 

 acid which wants correcting ; but in all other soils, it should be 

 proportioned to the inert vegetable matter the soil contains, and 

 be governed by the quantity of calcareous matter already mixed 

 with the earth. 



In the Mendip Hills the soil, being a very thin surface of gra- 

 velly loam on a limestone soil, has received great advantage in a 

 very puzzling way, from being treated with hot lime, such as to 

 change the price of land from 4s. to 35s. per acre. Quantities of 

 dung were placed on it without effect, till followed by hot lime, 

 but after that, it produced astonishing crops : of course the 

 animal matters got surrounded with lime, which rendered them 

 perfectly inert, till hot lime decomposed the other, and made the 

 whole soluble. This also shows why dung and carbonate of lime 

 will not do when placed together, as Sir H. Davy declares: the 

 reason why magnesiau lime acts in general as a poison, instead 

 of a manure, is, " that if there is not much vegetable matter in 



