8 INTRODUCTION. 



It is doubtful if any branch of horticulture has received less 

 aid from science than that which forms the subject of the present 

 work. Science has indeed been brought to bear upon horticul- 

 tural generalities', but, as far as regards its application to exotic 

 horticultural details, it is little better than a sealed book ; and 

 hence it is that we find cultivators clinging to antiquated sys- 

 tems, which the plain demonstrations of science and practice are 

 daily proving to be absurd. Amateurs, who adopt exotic horti- 

 culture as an amusement, and pursue it wnth enthusiasm, are 

 very apt to be misled by the advice of those who are more igno- 

 rant than themselves. They are easily led into extremes ; and 

 nothing is more common than for such persons, in their zeal, 

 to adopt one error, under the plausible pretext of avoiding 

 another. 



From the importance of Light, Heat, and Air, in the econo- 

 my of vegetable life, it is obvious why an architect is profession- 

 ally incapable of constructing a house for the growth of plants 

 or exotic fruits, without possessing a knowledge of the require- 

 ments and functions to be performed by the silent inhabitants ; 

 and hence it is, that, by studying these principles in connection 

 with other branches of science, we arrive at the end more rapidly 

 and successfully. In other words, cultivation becomes more cer- 

 tain as it becomes more scientific. Practical illustrations will 

 hereafter be given, to show that horticultural structures, instead 

 of being subordinate to architectural arrangements, as they gen- 

 erally are, must be accommodated to the necessities and require- 

 ments of vegetable life, before satisfaction can be afforded to the 

 possessor, or cultivation carried on in perfection. 



If we take a glance at the progress of horticulture in Europe 

 during the last twenty years, we cannot fail to perceive that its 

 advancement has been parallel with the developments of chemi- 

 cal and physiological science. Almost every succeeding year 

 has brought with it some new and important improvement in 

 practice, and thrown additional ligbt upon some hitherto disputed 

 question. Although gardening has, in some solitary instances, 

 been remaining stationary, the cause is by no means obscure. 

 Gardening is encouraged just in proportion to the satisfaction 

 it affords. It ogives satisfaction accordinir to its success, and 



