FEB.] THE HOT-HOUSE. 185 



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 82, and the amount will be those of Fahren- 

 heit. 



To convert the degrees of Fahrenheit into those of Reaumur : sub- 

 tract 32 from the degrees of Fahrenheit; multiply the remainder 

 by 4 ; divide the product by 9, and the quotient will be those of 

 Reaumur. 



Your fires must be continued every evening and night, being care- 

 ful in very severe weather to keep them burning, and sufficiently 

 supplied with fuel till so late a period that there can be no danger 

 of the house becoming cold before morning. Indeed, unless your 

 house is well constructed, there may be some severe weather in which 

 it would be necessary to keep up the fires all night. There have 

 been instances of careless persons intrusted with this work, who, in 

 order to get to bed at an early hour, or to some idle frolic, have put 

 down large and violent fires, which never fail to do injury to the 

 plants, and sometimes to burst the flues ; this practice is to be care- 

 fully avoided, as a moderate and steady heat is what always will 

 insure the best success. 



The fires are to be renewed very early in the morning, and con- 

 tinued until the heat of the sun is sufficient to promote a comforting 

 warmth in the house ; and in very cold and dark weather, it will be 

 necessary to keep them burning all day. 



It is very advisable, and indeed indispensable, for the health of 

 the plants, to sprinkle the flues and floor occasionally with water, in 

 order to restore the parched air of the house to its atmospheric 

 quality ; this will not only render great service to the plants, but 

 tend to weaken the power of destructive insects ; for these do not 

 like a moist air, manifested by their greater increase in dry stoves, 

 than in others. 



A proper degree of heat must now be preserved in the bark-bed, 

 for nothing can contribute so much to the free growth of the young 

 fruit as a brisk bottom-heat; if the roots have not this advantage, it 

 is impossible to make the fruits swell to any tolerable size. 



Therefore, wnere the bark-bed was not stirred up the former 

 month, to renew the fermentation, and revive the declined heat, it 

 should now be done, for the heat will consequently now begin to be 

 very faint, and by stirring up the bark almost to the bottom, it will 

 bring on a fresh fermentation therein; by which means the bed will 

 again recover a lively growing heat, the good effect of which will 

 soon appear both in the plants and fruit, provided it be done in due 

 time ; but if the heat is greatly decreased, and the bark decayed, you 

 may augment it at the same time with about one-third or fourth part 

 of new tan, otherwise defer it till next month, which see. 



However, where the work of forking up the bark-bed appears 

 necessary at this time, agreeable to the observations above men- 

 tioned, it should, if possible, be done in the first week in the month ; 

 for if it is delayed much longer, the plants and fruit will certainly, 

 for want of a due proportion of heat, be much checked in their growth. 

 Observe, in the first place, to take all the pots out of the bed ; then 



