358 THE PHILA DELPH IA FLORIST. [No. 12 



working the soil — giving back through the medium of manures the^j 

 ingredients extracted by continual cropping — and a proper system of °D 

 rotation in crops are all equally essential to remunerative success. — 

 The importance of deepening and pulverising the soil, is pretty gener- 

 ally recognised by all good cultivators. Our forefathers recognised 

 the principle in their summer fallowing, and more modern ingenuity 

 has brought the subsoil plough to its aid. We also read of one Jethro 

 Tull, who maintained that pulverisation was the only requisite to 

 secure a succession of bountiful crops. The theory upon which these 

 practices are founded has of later years been properly explained. 

 Since vegetable chemistry has been recognised as a branch of natural 

 philosophy, and become the subject of scientific research, most im- 

 portant truths have been discovered, errors in practice corrected, and 

 causes of failure made clear; true principles deduced, and results 

 arrived at which were hitherto considered unattainable ; but the diffi- 

 culty of arriving at principles of universal applicability becomes 

 apparent when we consider the various influences to which vegetation 

 is constantly subjected; the modifying effects of climate and atmos- 

 phere; the different combinations of the elements constituting the 

 soil; and above all, the limited knowledge concerning the laws of 

 vitality, and the influence that vegetable life has in rendering these 

 elements subservient to its use. Neither can it be doubted that the 

 occasional discrepancies between the deduction and application of 

 scientific principles arises from the fact, that the requisite knowledge 

 to deduce and apply is seldom combined in the same individual, and 

 while the scientific man reproaches the practical cultivator for his 

 indifference to the revelations of science, and his prejudice for old 

 established customs, the latter reminds him of the want of harmony 

 among men of science, and the varied opinions held by them upon 

 the same subjects. It has also been remarked, that behind even the 

 most extravagant and fantastic prejudices', it is seldom that there is 

 not some lurking truth upon which they are founded, of undoubted 

 and indisputable value. 



Both science and practice agree in confirming the beneficial results 

 of the frequent exposure of soil to the air, disintegrating the mineral 

 bases and rendering it a fit medium for the ramification of roots. But 

 it is not on the surface alone that these preparations are necessary, 

 roots must be enticed down, and this is only to be effected by deep 

 aeration. Trenching is undoubtedly the most thorough process of 

 loosening and deepening the soil. The advantages of this operation 

 are various; the surface soil that has been exhausted by continual 

 I cropping, is replaced by a portion of subsoil enriched with the nutri- 

 CV tive matters that have naturally sunk and been washed down by rains 

 j^from the surface, and carried beyond the reach of the roots; the Cm 



apDv_- -s&m " 



