REGULATION OF HEAT, &C. 165 



the most essential points in forcing, a good ther- 

 mometer is necessary in the pinery and all other 

 forcing houses, that the heat may be properly 

 ascertained, and without which a proper standard 

 degree, cannot be so conveniently maintained. 

 This should be hung up in the centre of the 

 place, with the back towards the sun, in an up- 

 right position, that the spirit in the tube may be 

 regulated only by the internal heat in the place, 

 and the heat kept as regular as possible during 

 the various forcing months, in such advances as 

 will be directed. 



In the month of January, the thermometer 

 requires the greatest nicety in its arrangement 

 in every description of glass house ; indeed, if 

 properly understood, it will greatly serve as a 

 guide to all seasons of the year. As the days 

 lengthen, the pinery will require a higher tem- 

 perature, from 50 to 55 degrees, and before the 

 end of the month to 60, advancing the tempera- 

 ture in proportion as the spring advances, until 

 it reaches 80, about May ; and for the main 

 fruiting pinery, 85 degrees, or rather higher, 



