By Edward Solly, Esq. 



conclusion, however, it must be remembered that as the nature of 

 the inorganic substances absorbed by plants, varies as well as their 

 quantity, it does not follow that that plant which takes up most 

 earthy matter does most injury to the soil. It is in fact more pro- 

 bable that the amount of Phosphoric acid taken up by the crop 

 would be a fairer standard of exhaustion ; but even this does not 

 seem to be quite accurate in all cases, because though in some 

 experiments it was found that the earthy matter bore a smaller 

 relation to the organic matter,, just in proportion to the quantity of 

 Phosphoric acid it contained ; yet there were so many exceptions 

 to this rule, as to render its applicability very questionable. 



Previous experiments had made it appear probable that some 

 relation existed between the rapidity of growth, and the pro- 

 portion of earthy matters existing in the plants. In the experi- 

 mental Peas (p. 86) very little effect was produced by the various 

 manures employed ; Common Salt and Nitrate of Soda slightly 

 improved the growth of the plants, they were rather larger and 

 more flourishing than the other ten squares, but the produce in 

 seed was rather less. In July, when the seeds were fully formed, 

 hut still quite soft and green, they were examined ; the following 

 Table shews their composition, and the relation of inorganic to 

 organic matter at this time. 



Three months later, when the Peas were perfectly ripe, and had 

 been gathered in and weighed, they were a second time examined; 



