BXPEEIMENTS ON TEMPEEATUEB BY EDWAKDS AND COLIN, 231 



seeds, that, how well soever a plant may grow at the minimum 

 temperature of its native locality, the maximum temperature of 

 that spot ought to be maintained while the seeds are vegetating. 

 We have no exact experiments upon this subject, except in a 

 few cases recorded by Messrs. Edwards and Colin, by whom 

 there is a very valuable set of observations upon the tempera- 

 tures borne by certain agricultural seeds (Annates des Sciences, 

 Snd series, vol. v. p. 5), the result of which may be thus 

 stated : — 



At 44-6', Wheat, Barley, and Eye coiild germinate. 



95°, in water, for three days, ^ of the Wheat and Rye, and all the 



Barley, were killed. 

 104°, in sand and earth, the same seeds sustained the temperature 



for a considerable time, without inconvenience. 

 113°, imder the same circumstances, most of them perished. 

 122°, ditto ditto all perished. 



But it was found that, for short periods of time, a much 

 higher temperature could be borne. 



A 



At 143-6, in vapour, Wh^at, Barley, Kidneybeans, and Flax retained 

 their vitality for it q^uarter of an hoxu: ; but m 27-i^ minutes, 

 the three last died at a temperature of 129'6°, 



167°, in vapour, they all perished. 



167°, in dry air, they sustained no injury. 



It will be presently seen that some seeds will bear a much 

 higher temperature. 



" In order to render this important subject yet more .clear, we subjoin 

 a report on the labours of Edwards and Colin, derived from the pages 

 of Froriep's Zeitschrift. Messrs. Edwards and Colin read an article 

 upon this sjibject before the Academy pf Sciences on the l-8th of April, 

 1837, which ooMtitutes the third pact of their Mesearches upon Agri- 

 cultural Physiology. Their experiments led to the foUowing results : — 



1. "Jn ifree moist air, yet considerably removed from the point of 

 saturatican, seeds did not germinate. 



2. " Germination took place among Cereal plants, Summer Wheat, 

 Winter Wheat, Barley, Oats, Eye, when placed in an atmosphere fully 

 saturated with moisture. 



S. " When placed under water they required eight times as long a 

 period before they germinated. 



