84 BRITISH MODES OF CULTIVATING 



And in the hottest countries in the world, where 

 vegetables and animals exist, the heat in the shade 

 seldom rises to blood heat, which is about 97- 

 Having considered these things, and ascertained 

 that a plant can endure a heat of 130 degrees, I 

 determined to try another experiment, that is, to 

 ascertain whether heat and water would destroy 

 insects, and keep plants alive. I therefore thought 

 of, and determined to try, the following method : 



66 In the month of June I selected about twenty 

 large Pine plants, some of which had green fruit 

 on them, and their leaves, fruit, and roots, were 

 almost covered with insects. These plants I plung- 

 ed in a tan bed, with a very gentle heat in it. The 

 tan bed was in a brick frame designed for rearing 

 succession plants : it was nearly five feet wide, 

 twenty feet long, and the glass frames were close 

 and in good repair. These plants I watered fre- 

 quently and plentifully, sometimes twice a day, 

 with water not less than 70 or 80 degrees, and 

 sometimes 100, warm: in short, I kept the plants 

 constantly in a moist air, by plentiful waterings 

 without measure ; and, excepting the time of giv- 

 ing water, I kept the lights constantly close shut 

 down, even in the hottest sunshine, without shading 

 the plants. In this frame I had no thermometer, 

 but the heat was, I think, sometimes about two or 

 three o'clock' in the afternoon, upwards of 120 de- 

 grees. This great heat and much moisture: caused 

 the plants to grow most vigorously ; and having 

 subjected them to the said mode of management 



