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says: "Cotton will be seriously injured by a low tempera- 

 ture early in the spring whether frost occurs or not." "No 

 adequate means of protection against cold and frost, suitable 

 for general use, has been discovered." Another writer 

 (John Tyndall) says : "Sudden changes of temperature are 

 prejudicial to animal and vegetable health." This point 

 may be farther illustrated by the following instance : A 

 florist early in May discontinued the fire in his hot house 

 devoted to Pelargoniums, as he had but a small supply of 

 fuel on hand. His method was to close the ventilators early 

 in the afternoon and thus store up heat for the night. Up 

 to the time that the fire went out the plants Avere healthy 

 and green, with only an occasional yellow or reddish leaf. 

 In about a week after he ceased firing, all the lower leaves, 

 being fully one-third of the total foliage of the central bed 

 and a part of the south side, changed to red ! Those on the 

 north side, and those close to the south side which were 

 partially shaded by the framework of the roof and side, 

 retained their original verdure. The central beds had the 

 full benefit of the direct rays of the sun. The day tempera- 

 ture was probably a little higher in the afternoon, and a 

 little lower in the morning, but averaging about the same 

 as before for the daytime, while the night temperature was 

 probably 10"^ or 15° lower, as there were some frosty nights. 

 The plants were ventilated and watered according to require- 

 ments, and it is believed that there could not have been any 

 frost within. That the red color was induced by the changes 

 in temperature there could be little doubt. They had pre- 

 viously experienced as much heat by day, and the only spe- 

 cial difference was the lower temperature at night. It has 

 been mentioned that the plants partially shaded were unaf- 

 fected ; it was only those subjected to hoth extremes of heal 

 and cold that became red. As a further test of the real 

 cause of the red leaves, several of the potted Pelargoniums 

 and also of Ampelopsis Veitchii were plunged into the 

 ground in the open air. There was a hoar frost soon after 



