TABLES OF TEMPEKATURE. 



117 



HYl. — Tables of Temperature, for the use of Gardeners; 

 arranged according to the Latitudes of the respective localities 

 iji ivhich the Observations have been made. By Robert 

 Thompson. 



The indigenous objects of horticultural care are few, compared 

 with the vast number that are exotic. As to these, the first con- 

 sideration ought to be tlieir natural climates, especially with 

 reference to temperature, in order to determine, in the first in- 

 stance, whether they should be treated as hardy, half-hardy, 

 greenhouse, or stove plants ; whetlier they are suited for only a 

 mild and nearly equable temperature, or are adapted for sustaining 

 great extremes of heat and cold. The importance of obtaining 

 correct data for the determination of these points will be readily 

 acknowledged. It is remarked in ' The Theory of Horticulture,' 

 p. 102, that " To collect together evidence as to the real amount 

 of temperature at the different seasons of vegetation, in various 

 parts of the globe, would be to render a most important service 

 to horticulture ; for it is hopeless to expect that the cultivation 

 of plants can be perfect, in the absence of one of the first data 

 that require to be ascertained. What, for instance, are the 

 terrestrial and atmospheric temperatures of the melon-fields of 

 Persia, Bokhara, Spain, or Smyrna, where that delicious fruit 

 acquires its greatest excellence ?" 



In general plants will bear the extremes of heat and cold which 

 occur in their native countries without being killed in conse- 

 quence of temporary exposure to such vicissitudes ; but they may 

 be made to perish gradually by subjecting them to a temperature 

 either constantly above or constantly below the mean temperature 

 of their native climate during the period of vegetation. It 

 therefore becomes desirable to know the mean temperature, not 

 only of the whole year, but also of the respective months in every 

 place from which plants are obtained. This would prevent 

 serious mistakes and losses in many instances ; and, although it 



VOL. IV. K 



