78 AfV GARDEN. 



It then falls and becomes heated again, and the process is repeated 

 till the air becomes so dry as to be hurtful, and thousands of plants 

 are annually destroyed. This we avoid at my garden by continually 

 supplying to the air an amqunt of moisture judiciously adapted to 

 the peculiarity of the plants. 



WARMING OF GLASS-HOUSES. 



The simplest mode of obtaining artificial heat is by the use of 

 hot dung. The fresh dung from our .stable is moistened with water and 

 turned over several times, for the sulphur and other coarser products 

 to be exhaled. Whenever leaves can be procured and mixed with 

 the dung, they moderate the heat and cause it to last for a much 

 longer period, and hence we use this mixture for our early potatoes. 

 When the frame is made up the first fiery blast is allowed to pass off, 

 and the gardener ascertains the proper time to plant by inserting a 

 stick into the materials of his hot-bed. The heat after a time abates, 

 when he uses a lining round the frame to maintain in early spring 

 the necessary temperature. Sometimes fermenting materials are used 

 in houses for forcing grapes in early spring, but I have never myself 

 so applied them. 



Spent tan is employed, especially for the growth of pines. It 

 is particularly liable to facilitate the growth of the tan fungus, and, 

 therefore, we only employ it in our little pine-pit. 



In all systems of warming by the combustion of coal, coke, wood, 

 oil, or naphtha, the heat developed bears a relation to the amount of 

 the matter consumed ; hence all that an engineer can effect is to 

 regulate the application of the heat when generated. He cannot in 

 effect generate heat without a corresponding change of matter. 



From the time of the Romans rooms have been heated with flues, 

 and within a few hundred yards of my garden they were employed nearly 

 two thousand years ago. By this plan the direct heat of a stove is 

 carried round the house in brick flues. This plan I have not used, as 

 modern science has directed us that it is better to have our fireplace for 



