HEATING OECHID HOUSES. 63 



better to spend a little more money for material at first, than 

 have to make additions afterwards. By having plenty of pipe 

 a less rapid combustion is required, which is better for the 

 plants, and the expense is saved in fuel in a very short time. 

 We therefore advise four rows of pipes on either side for the 

 East Indian house, three for the Brazilian, and two for the 

 house devoted to those species from New Grenada, Peru, and 

 some parts of Mexico ; by having four pipes for the plants 

 requiring most heat, one does not require to drive the fire so 

 much on a frosty night. We never raise steam from the 

 pipes ; for plenty of moisture can be obtained without it, by 

 pouring water on the tables and paths, which we consider 

 much better than steam discharged on the plants direct from 

 rusty pipes. At the same time, we do not by any means con- 

 demn the use of evaporating troughs during the summer 

 months, for these will difi"use throughout the house a most 

 congenial moisture, highly beneficial to the growth of the 

 plants, and the effects of this moisture is very difi'erent from 

 that of scalding steam. 



The boiler should be placed outside of the house, and not 

 set underneath, which is a very bad system. We remember 

 going to see a collection of Orchids where the boiler was so 

 situated, and had been put there to economise heat. The 

 plants were growing very freely at the time, and upon remark- 

 ing that we should be afraid of smoke getting into the house, 

 we were told .there was no fear of that, "for the boiler was 

 well covered over." Only a few months afterwards on calling 

 to see the same collection, we found our fears were realised ; 

 the smoke had got into the house, and had spoilt many of the 

 plants. This is merely mentioned to show the ill efiects of a 

 boiler being so set that smoke can get into the house. When 

 outside, there is no fear of such a disaster. 



There is more importance in the setting of a boiler than 



