A GENERAL SURVEY 5 



cal plants and thus of necessity kept at a high 

 temperature. The use of this term is more 

 common in England than in this country. 



A RANGE of greenhouses implies several 

 houses more or less closely connected and 

 under one management. The individual 

 houses may be of any one of the classes men- 

 tioned above or a combination of two or more 

 classes. Such houses are often spoken of as 



a RANGE OF GLASS. 



A range of forcing houses is sometimes 

 spoken of as a BATTERY, and a range of sash- 

 beds as a NEST. 



EVOLUTION OF THE GREENHOUSE 

 It is said that the Romans, even before the 

 time of Christ, possessed some knowledge of 

 the forcing of fruits and vegetables, and util- 

 ized for this purpose pits covered with slabs 

 of a transparent mineral. Heat was supplied 

 by fermenting manure, and occasionally by 

 furnaces of masonry in which a slow fire of 

 wood or dried manure was kept burning. 

 How successful they were we do not know; 

 but it seems certain that if any degree of 

 perfection was obtained, it was because of 

 the skill of the gardener rather than because 

 of any special merit of the forcing pits. 



