HARDINESS OF THE ORANGE-TKEE. 193 



perished, but not of the eold so much as the damp, for they were ex- 

 amined, and seen to be still safe in February, after the frost had reached 

 above 15° of Rbatjmite ( — 2° Fahk.), and perished a few days later 

 from a return of the cold, attended by the drippings of a preyious thaw. 

 I had the three which died replaced, and from that time to this they 

 have flourished and increased in size. I have them covered with a 

 round cabin of planks, roofed with straw on the outside, at the end of 

 October or beginning of November, and uncovered in April. They bear 

 abundance of Oranges and Lemons, the former occasionally becoming 

 eatable with sugar. At no other place in this country am I aware that 

 the experiment has been tried, unprotected by a wall. But with a wall 

 and a covering of wood and straw, to be taken off in the summer, I can 

 scarcely doubt that the plants might be made to grow, without the 

 clumsy accompaniment of large wooden boxes, in an English garden." 



This case establishes the fact that in the north of Italy the Orange-tree 

 bears a degree of winter cold unknown in England. For this it is 

 prepared by the complete ripeness of its wood, a state to which it can 

 never arrive in this climate in the open air. But are we therefore to infer 

 that it will not live with less shelter than it now receives ? Such an 

 inference is scarcely justified, and it is worth the consideration of those 

 who have Orange-trees at command, whether they wiU. not pass the 

 winter in barns, or dry out-houses, or under wooden screens where no 

 artificial heating is applicable. Dryness in such an experiment is the 

 first condition to secure ; darkness is the second. The Orange-tree will 

 bear to be deprived of water during the whole of its season of rest, 

 provided its roots are kept in the earth they grew in ; how much 

 dryness, beyond this, they will bear, is shown by the long exposure to 

 the air which they undergo in the shops of the Italian warehousemen 

 in London ; and experience tells us that the effect of cold upon plants 

 is feeble in direct proportion to their dryness. All trees kept in the 

 dark, or at least kept where no sun can shine upon them, will bear 

 without injury a degree of cold which would be fatal to them if ex- 

 posed, when frozen, to the direct rays of the sun. Camellias, Chinese 

 Azaleas, ladian Ehododendrons, and many New Holland plants, take 

 no harm in cold pits in winter, provided those pits face the north. 

 Some of them live out of doors perfectly well during winter, if under 

 north walls ; and we have in our possession a small Orange-tree which 

 passed the winter of 1853-4, when the thermometer fell to 4 ° Fahr. un- 

 injured in a cold pit facing the north. 



As to temperature in the open air, unconnected with 

 atmospherical humidity, there seems to be no means of regu- 

 lating or modifying it to any considerable extent. In some 

 respects, however, we have even this powerful agent under our 



