REGULATION OF TEMPERATURE 25 



of charming spring flowers hold up their heads in happy 

 contrast to their fellows in the garden outside. 



There are several other inventions for the purpose, none of 

 them perhaps without some drawback, and every season sees 

 new additions to the list. A demand seriously maintained 

 for a perfect removable apparatus of sufficient power to keep 

 out frost will surely call forth exactly what is required. 



It may be worth while to make a note of a very rough- 

 and-ready contrivance which has been successfully extemporised 

 on occasion for keeping out frost. An ordinary lamp is 

 lighted and placed on the floor, with a pillar of bricks on 

 each side to form a support for a very large flower-pot, 

 which is inverted over the chimney. Upon this a pyramid of 

 inverted pots, each a little smaller than the last, is built up, 

 and the hot air rising through the holes of the pots heats 

 them through and through, and thus a stove may be devised 

 on the spur of the moment which will diffuse an atmosphere 

 genial enough to keep the enemy, for the nonce, out of a 

 house of moderate dimensions. 



VENTILATION 



By some strange perversity the proper ventilation of the 

 amateur's greenhouse is often one of the last details of con- 

 struction to be considered, which would never happen if 

 experience could only be bought ready-made. Plenty of air 

 is as necessary to plant life as to human beings, and it would 

 seem to be as unreasonable to plan a greenhouse without 

 ventilation as to build a cottage with windows not made to 

 open ; yet it is by no means an unheard of case for a green- 

 house (mostly of the smaller sort) to have no other means of 

 ventilation than the door, while, even in more important 

 structures, roof ventilation is the exception rather than the 

 rule. For perfect efficiency there should be not ventilators 



