Feb.] THE HOT-HOUSE. £75 



The Aphides may be destroyed with a gentle fumigation; but 

 the Thrips and Coccus hesperidum require a smoke so strong, that 

 a person cannot distinguish an object farther than at the distance 

 of five feet. 



When a hot-house is greatly infested either with the Aphides or 

 Tlirips, the fumigations should be repeated every third or fourth 

 night, for three or four times successively. The reason and neces- 

 sity of these repetitions proceed from a probability that the smoke 

 cannot affect the insect in the egg, and perhaps it may not have 

 sufficient power over them in other of their states; therefore a fresh 

 brood may naturally be expected in a few days. 



Care of the Pines. 



Many of the pine plants will now appear set for fruiting, which 

 may be distinguished by the short leaves in their centres; from that 

 time they should be moderately watered and the house kept pretty 

 warm; for when plants are kept cold at the time of forming their 

 fruit, it generally causes many of them to be crooked, imperfect 

 and misshapen. Therefore, under such circumstances, never 

 let the heat fall lower than 55° of Fahrenheit, nor rise higher, 

 by fire-heat, than 62°; a little air should, however, be admitted 

 whenever the weather permits, and especially on sunny warm days, 

 when the heat rises to above seventy degrees. But in no case, nor 

 under any circumstances, let the heat of the house fall below 52°, 

 if possible. 



As some persons may be furnished with Reaumur's and not with 

 Fahrenheit's thermometer, it may be of use to give a comparative 

 table of their scales, as well as the rules by which one can be con- 

 verted into the other; observing that 32° of the latter, being the 

 freezing point, is equal to (or zero) of the former. 



