Sir Henry Steuarf^ Planter'' & Guide. 337 



elated by all who are interested in forest tree planting, parti- 

 cularly in the immediate attainment of the effect of trees of 

 large growth. To the artist in landscape-gardening, the dis- 

 covery is of great importance; but its value in this point of 

 view has been so amply detailed and discussed in the papers 

 above alluded to, that 1 need not farther dwell upon it here. 



In all the notices of the Planter's Guide which I have 

 perused, there appears to me to be one interesting and valuable 

 feature of it too slightly noticed ; I mean the happy union of 

 sound physiological knowledge with practical experience, which 

 Sir Henry Steuart displays in his work. 



To combine science with practice, or to show the depend- 

 ence which these have on each other, by facts clear and deci- 

 sive, obtained from daily practice, and which may be demon- 

 strated by repeating the same practice or processes of culture, 

 is an object of great importance, and difficult to arrive at, 

 because it requires many years' assiduous attention, observ- 

 ation, and unwearied labour. 



The advantages resulting from the union of scientific know- 

 ledge and practical experience are great; the former is as the 

 lamp in the dark, showing us where to place our steps in 

 safety, what to avoid and what to take ; leading us in the 

 direct path without loss of time, and without experiencing dis- 

 appointment, to the object we desire to attain. 



The physiology of plants, or the knowledge of the structure 

 and of the vital functions of vegetables, also a knowledge of 

 the nature or properties of the different soils which influence 

 the growth of different species, and that of distinguishing the 

 different species and varieties of plants which affect different 

 kinds of soils, are not only necessary but essential to the agri- 

 culturist who would exercise all the different branches of the 

 art with the greatest success, or at the least cost of time, 

 money, and mental and bodily labour. 



This knowledge also enables the possessor of it to communi- 

 cate an account of the results of his successful practice and pro- 

 cesses of culture, in language or expressions not easily to be 

 misunderstood, and free from those doubts or ambiguities which 

 often characterise otherwise valuable communications on agri- 

 cultural subjects, where empirical practice only has guided. I 

 may be permitted farther to observe, that practice is the 

 foundation of science, and that, till of late, these have been too 

 much kept apart; we have, in most instances, either all science 

 or all practice. Hence the unwillingness of most practical men 

 to receive information from reading, or what is termed book- 

 learning ; and it must be allowed so far in their favour, that 

 scientific or physiological knowledge, without a due corrective 



VoL.IV. — No. 16. z 



