of Science to Agriculture. 151 



ancl^ what is perhaps of equal importance, existing too in that 

 precise condition in which they are most readily taken in and 

 assimilated. 



Where this material is sufficiently cheap and abundant, 

 other kinds of manure may for the most part be dispensed with ; 

 but as in certain stages of society the amount of animal life 

 increases throughout a given region in a greater ratio than the 

 fixation of gaseous matters which takes place through the instru- 

 mentality of vegetables can proceed, and as the existence of large 

 cities tends to disturb the balance which nature seems to aim at 

 establishing between the quantities of food produced and con- 

 sumed, by attracting into their vortices a large proportion of the 

 corn and cattle that has been reared in the country, it is well that 

 we have at our command, in the various mineral manures which 

 science has brought to light, the means of supplying the defi- 

 ciency. 



But, assuredly, the most effectual, as well as the most eco- 

 nomical method of restoring the balance between the town and 

 country would be to avail ourselves of that enormous accumu- 

 lation of animal exuviee which the existence of a crowded city ne- 

 cessarily occasions, and to convert that which is now n pabulum 

 of disease into a source of life and abundance. 



As indeed the geologists of the present day cite as a proof of 

 the ignorance or neglect of their predecessors, that the stone re- 

 quired for the fortifications at Gibraltar was brought out from 

 England, when it might have been obtained upon the very spot ; so I 

 conceive our descendants will marvel at the inattention to chemical 

 science evinced by the present generation of farmers, in exporting 

 from distant regions, such as South America, substitutes, and those, 

 perhaps, but imperfect ones, for that fertilizing material, of which 

 the greater part is allowed to deposit itself unprofitably in the 

 beds of our rivers. 



Not that I would by any means be supposed to discourage, 

 under present circumstances, the importation of fertilizing ma- 

 terials from abroad. Some of these, such as the Guano, lately 

 introduced into this country from the islands of the Pacific, 

 contain ammoniacal salts in a more concentrated form than any 

 other known species of manure ; whilst others, such as bone-earth, 

 comprise within a given compass a larger amount of phosphoric 

 acid — hence their portability may give them advantages, by secur- 

 ing greater economy of transport, in spite of the distance from 

 whence they are brought : nor must we forget, that the measures 

 for carrying off filth adopted in large cities are of a nature 

 which would preclude us from obtaining it in sufficient quantity, 

 in case that any great increase in the demand for it^ as a manure, 

 should hereafter be created. 



