160 A New Plan for constnicting Greenhouses. 



front and two sides, extending into the cellar. The walls 

 were stone laid in mortar, as high as the surface of the 

 ground ; above the ground, to the under side of the floor of 

 the piazza, with brick ; the front wall being no higher than 

 the surface of the ground. The excavation was five feet 

 below the gravel walk. Upon the top of the walls was 

 placed a plank frame, arranged for the sashes, with inter- 

 vening rafters. The sashes run under the floor of the piazza, 

 and are fitted so as to be secure against storms. The under 

 side of the piazza is lathed and plastered. Thus you see 

 there is nine feet deep by two feet high enclosed with glass ; 

 the floor of the piazza covering the other portion, and all 

 laying open to the cellar. In the cellar is a furnace for 

 warming my house, but no arrangement for warming the 

 greenhouse especially ; it receives some heat, however, from 

 so large a mass of brick being kept at a temperature of some 

 forty to fifty degrees. It will be noticed that in using a 

 furnace for warming a dwelling house, the variations of tem- 

 perature are favorable for the wants of the greenhouse ; as, 

 in very cold weather, the furnace is heated, by the extra 

 quantity of fuel, much hotter ; and this necessity communi- 

 cates an equal proportion of heat to the inclosing brick work. 

 Another advantage in its (the greenhouse) connection with 

 the cellar is, that as the air cools in the greenhouse during a 

 cold night, it falls and is replaced by warmer air from the 

 cellar ; so that there must be a succession of cold nights and 

 days to lower, essentially, the temperature of the whole 

 cellar, with its walls and contents. 



The thermometer, during the severe cold of the last win- 

 ter, (1851-2,) stood at 40° above zero at 11 P. M. This was 

 sufficient heat to keep the most tender of my plants from 

 suffering. It will be readily understood that plants will bear 

 this low degree of heat that have become inured to it, and 

 have been in a particular state of rest. There are many that 

 will grow during the winter in my house, and make consid- 

 erable top ; and I think there is not an exception to their 

 making rootlets. No one would think of attempting to grow, 

 at this temperature, a class of hothouse plants ; neither would 



