./. //. anuvi -point* 



rlth V, v ,l„tl, 



195 



and its atmosphere, the question arises whether, assuming the 

 "iiiim to be independent of the direct action of vegetation, the 

 large accumulations within our soils and subsoils, admits of any 

 reasonable explanation ? On this point it may be remarked, 

 that ages <>i forest growth, or ol the uTowth of natural herbage 

 only grazed by animals, would doubtless leave the soil richer 

 year by year; as the amount annually lost to it would probably 

 • less than even the small amount known to be annually de- 

 i 1 "" 1 '' """tl 'atmosphere m temperate regions, at the present 

 time; and the accumulation would probably be greater still, 

 were the amounts of combined nitrogen in the atmosphere, and 

 brought down from it, greater than with us at the present time. 

 I hen. again, the influence on aqueous deposits of ages of sub- 

 marine vegetation, and of the subsistence of animal life upon it, 

 has to be considered. But a soil once broken up, and under 

 arable culture, it is difficult to conceive of anv svstem of aori- 

 '■ulture by which so little ni.._ G 

 tively determined to be annually dc 

 would be annually exported from t 



Conclusion.— AJiA no 



suits of the whole disc. 



deuce points to the conclu 



•' thes 



- that hitherto quantita 

 i the atmospher 



in a few words the re 



ision, I think the balance of the evi 



ion, that the answer to the question— 



™„-v,osof then. MU «, 



?l agricultural productions in particular, is more likely to be 

 touu.i in the relations of the atmosphere, and of the piant, to 

 the soil, than in those of the atmosphere to the plant itself. 



One word more in conclusion. I have, as explained at the 

 outset, confined attention almost exclusively to one aspect of 

 the great subject of vegetation : but it will not be supposed that 

 1 have done so from any want of appreciation of the interest 

 ""^importance of other lines of inquiry; and allow me, before 

 closing to allude to a point which can hardly fail to suggest it- 

 self on an inspection of the numerous organic compounds, made 

 by transformation in the laboratory, which are collected in the 

 Section of this Exhibition. Without in the least de- 

 gree disparaging such work, I would ask whether some of those 

 who have become masters of such transformations, might not 

 -ag'. armed with the experience thus gained, now 

 ■ nselves to the study of the transformations going on 

 e plant and theanimal? In other words, whether it 

 1 1 -n i I tl t - m t tin th ugh mil labor now 

 •■"i transformations in the chemical laboratory should 

 be transferred to the laboratory of nature? 



