168 THE HOT-HOUSE. 



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

 Thrifts, 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 mis-shapen. Therefore, under such circumstances, 

 never let the heat fall lower than 55 of Fahrenheit, nor rise higher 

 by Jire-hcat, 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**: 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. 



Reaumur's Fahrenheit's Reaumur's Fahrenheit's 



Degrees 16 68 Degrees 33 106,2 



15 65,8 32 104 



14 63,5 31 101,7 



13 61,2 30 99,5 



12 .59 29 97,3 



11 56,8 28 95 



10 54,8 27 92,7 



9 52,5 26 90,5 



8 50 25 88,2 



7 v 47,7 24 86 



6 45,5 23 83,8 



5 43,3 22 81,5 



4 41 21 79,2 



3 38,6 20 77 



2 36,5 19 74,7 



1 34,2 18 72,5 



32 17 70,3 



To convert the degrees of Reaumur into those of Fahrenheit. 

 Multiply the degrees of Reaumur by 9, and divide the product by 4 ; 

 to the quotient add 32, and. the amount will be those of Fahrenheit. 



