Vegetable Staticks. 39 



u Frozen concave clouds therefore, by their 

 cc great reflections, produce a vigorous heat, 

 " and the fame, when refolved, exceffive 



« cold." 



Whence we fee that blafls may be occa- 

 lioned by the reflections of the clouds, as 

 well as by the above mentioned refraction of 

 denfe tranfparent vapors. 



July 21. I obferved that at that feafon 

 the top of the Sunflower being tender, and 

 the flower near beginning to blow, if 

 the Sun rife clear, the flower faces towards 

 the Eaft ; and the Sun continuing to fhine, 

 at noon it faces to the South 5 and at fix in 

 the evening to the Weft: And this not by 

 turning round with the Sun, but by nuta- 

 tion; the caufe of which is, that the fide of 

 the ftem next the Sun perfpiring moft, it 

 fhrinks, and this plant perfpires much. 



I have obferved the fame in the tops of 

 Jerufalem-artichokeSy and of garden-beans* 

 in very hot Sun-fhine. 



Experiment X. 



July 27. I fixed an Apple-branch, m, 3 

 feet long, ~ inch diameter, full of leaves, 



D 4 and 



