GERMINATION OF THE SEED. CHAP. I. 



seeds germinate faster in the shade than in the sun, 

 and hence concluded that light is prejudicial to ger- 

 mination. Senebier,* who afterwards repeated the 

 experiments of Ingenhoutz with the same result, 

 drew from them also the same conclusion. 



But it remained to be determined whether the 

 prejudicial effect was to be attributed merely to 

 the light, or partly to the heat accompanying it. 

 From the experiments of Ingenhoutz and Senebier, 

 the injury appeared to be occasioned by the light 

 only ; because the comparative experiments in the 

 shade and in the sun, were made at equal tempera- 

 tures as indicated by the thermometer. With this 

 conclusion, however, though apparently legitimate, 

 Of Saus- M. Saussure professes to be dissatisfied, because the 

 thermometer placed even under the recipient is, 

 in his opinion, incapable of indicating the actual 

 degree of the heat of the solar rays impinging on 

 the surface of the seeds, which he believes to be 

 carried to a very great height, though still escaping 

 our instruments of observation. But this mode of 

 reasoning is, to say the least of it, still more in- 

 consequential than the former ; because it is setting 

 up a mere probability from which nothing can be 

 inferred, in opposition to a direct fact, from which 

 something surely should be inferred. It may in- 

 deed be true, that the degree of heat impinging on 

 the surface of the seed is so great as to impede its 

 germination ; but as no direct proof can be adduced 

 in support of the opinion, we must just rest satis. 

 * Mem. Phys. Chim. vol. iii. p 341, 



iure. 



