CULTURE OF THE GRAPE. 55 



is represented as open, to let the heat pass from the tank 

 into the house. This will be found necessary in cold 

 weather, but only to a moderate extent. The object is 

 to "keep the feet warm and the head cool." A glance 

 will show how perfectly this paramount condition is se- 

 cured. The boiler, e^ may be of the smallest size, and 

 kept exclusively for this house, which should work - inde- 

 pendently of all others. I have not thought it necessary 

 to give all the reasons determining the above construc- 

 tion, nor the many modifications and other forms which 

 are now in use. This would require too large a sjJace in 

 a treatise for general use. Suffice it to say, that after 

 years of trial, and many disappointments, I have come to 

 the conclusion that the above simple and cheap plan is 

 nearly perfect. It only requires care, and the observance 

 of a few, the simplest rules, to propagate almost any 

 known plant. 



For large establishments, should more space than a 

 distance of sixty feet would secure be desired, it will be 

 better, as a general rule, to begin a parallel house on the 

 ridge and furrow principle. Succession-houses are a ne- 

 cessity in commercial gardens ; and the conviction is now 

 general, that ridge and furrow houses are most economi- 

 cal. By this term is meant a succession of parallel houses, 



