298 On tlte Coverings far Cucumber Frames. 



the manner of thatch, the water runs off from its surface, 

 and its interior remains perfectly dry, so that there is no con- 

 sumption of heat from the creation of vapour in those parts 

 which are near the glass ; whereas mats, cloth, and other 

 similar coverings, become impregnated with moisture every 

 night from dew, rain, or snow, and the evaporation which is 

 thereby constantly generated, and greatly augmented by the 

 contact of the warm glass, causes a vast and continued drain 

 of heat. The first of these objects is attained by the usual 

 method of strewing loose straw or hay over the mats ; but 

 this, which is so troublesome, as to be often neglected, or 

 done in a slovenly manner with damp materials, does not in 

 any degree promote the second ; for this irregular covering 

 does not prevent the water from penetrating to the mats, 

 from which the refrigerating evaporation is the immediate 

 consequence. 



Besides these advantages, the thatch coverings are at- 

 tended with less trouble than others, being moved off and 

 on with one action, in a moment, and there is not that risk 

 of breaking the glass, which arises from putting pieces of 

 wood or bricks over the mats, to prevent them from being 

 blown off, as is often done. 



These coverings are not only well calculated for Cucumbers 

 and Melons, but may be used with great advatage in pre- 

 serving tender plants during the winter. A pit or frame 

 earthed up all round, and covered with one of them, or 

 with two or three, if needful, upon each other, in the nights, 

 and during severe weather, will be completely impervious to 

 frost ; and I have no doubt that it will preserve plants of 

 most kinds in a healthier state than a common green-house. 



