106 Warmth and Moisture in Plant Structures. 



save it. All the head died during the first summer after plant- 

 ing, and now life lingers only on one side of the stem. 



Similarity of soil and aspect will be found to be the safest 

 guide in the successful removal of grown up trees ; but I would 

 say, above all, never attempt to move from a damp to a dry 

 ground, as the chances are fifty to one against success. 



Castle Ashby, December, 1841. 



Art. VIII. On inarming and moistening, and on preserving Heat 

 and Moisture in Plant Structures. By N. M. T. 



This severe time of the year, when the climate of hothouses is 

 purely artificial, and much force required to counteract the 

 rigour of the natural one, affords the best opportunity to as- 

 certain which of the many devices applied to effect this is really 

 best adapted to the purpose. If a certain degree of heat or any 

 single quality constituted a congenial atmosphere, the question 

 would be of easy solution, and the many claimants of superiority 

 easier brought to the test of proof ; but the numerous requisites, 

 and their necessarily accurate proportions, render it a most dif- 

 ficult task. Whatever besides may be required, heat to a 

 certain degree is indispensable ; and it is astonishing to think of 

 the progress that was made, particularly in the culture of fruit, 

 when this was held to be almost all that was necessary. Next 

 to heat, moisture holds the most important place; nevertheless, 

 until lately it was in a great measure overlooked, and, when 

 taken up, has, in all probability, been carried too far; at least 

 much has been scientifically urged as of the greatest importance 

 that is of little moment in practice, and to which I cannot en- 

 tirely subscribe. I allude more particularly to the ruinous drain 

 said to exist upon the moisture of the house, caused by the dis- 

 crepancy between the external and internal atmospheres. 



I object to the extent to which this has been carried, simply 

 because I do not think that it is an evil of the magnitude repre- 

 sented ; since, if it were, vegetation would more materially suffer, 

 and preventives properly applied would prove beneficial, which 

 is not the case. The now nearly obsolete brick flue, by ab- 

 sorbing considerable moisture from the air of the house, and 

 carrying it out with the smoke and waste air, is said materially 

 to aggravate the evil. This to me is not evident. I am not 

 going to advocate flues, being convinced that there are sub- 

 stitutes vastly superior ; still this is no reason that they should 

 suffer any unfounded imputations. The charge I consider 

 nearly unfounded, for the following reasons. A piece of cast-iron 



