M. 



abl 



nia 



y 



^Hr, 



u 





5nfifls i 



Sin 



tb at by 

 • into ail 



es 



1 



-2(1 from 



25. But 

 . folid 



or 



5 lisht at 







:rty fom 



e 



1 



fhlne, Is 



mities of 



ydrogefl 



1 Botanic 



decree is 

 



0- green, 



[ believe 

 perfpire 



J 



> 



is previ- 

 k becau 



is proc^ 

 fe the fol- 



fs 



ilarp 



01 



he 





Sect. XIII. i. 2. 



ELECTRICITY. 



297 



Sir Benj.Thompfon, now Count Rumford, In a paper publiflied 

 Phllof. Tranfaa. Vol. LXXVII. put thirty grains of raw filk pre 



fly wafhed 



1 



fome fpring water, and 



X 



fuigr it fo 



the funfhinc obtained from it very p 



to 

 In 



periment the fpring water feenas to have been in a ftate of hy 



per-oxygenation, and the points or fine ed 

 afTifted its liberation from the water in the funfh 

 Botanic Garden, Vol. 11. note on fu 



f the raw filk 



as ex 



plained 



The hyper-oxygenated 



part with its fuperabundant 



^. Mr. Scheele inverted a glafs veffel filled 



very haftily 



marine acid is known 



oxygen in the funfhine. ^ 



wi'th colourlefs nitrous acid into another glafs-veffel containing the 



fame acid ; and on expofing them to the fun's light, the inverted glafs 



became partly filled with pure air, and the acid at the fame time be- 



came coloured. Crell's A 



786 



As water contains 85 hundredth parts of oxygen to 15 of hydro- 

 gen, it may become much oxygenated occafionally by a fmall lofs of 



hydrogen in the vegetable fyftem ; or by the carbonic acid being d 



pofed in plants by the fecretion of carbon 



ch 



ftitutes fo 



crreat a part of them ; and that on both of thefe accounts they may 

 yield oxygen gas, when expofed to the fun's light, as appears from the 

 following experiment related from Von Uflar by G. Schmeiffer. Ob- 

 fervat. on Plants. Creech, Edinburgh, p. 92. 



If two branches of a plant are immerfed, one in common water, and 



b 



the other in water impregnated v.'ith ( 

 that the branch immerfed in the latter 

 tity of oxygenous gas in the funfhine than the oth 



d. we th 



find 



yields a much greater q 



The difF( 



fome experiments h 



found in the prop 



f 



But the proportions vary when different pi 



fubje£led 



64 



Thus the carbonic acid, with which the water is impregnated, is d 



compofed by the branch 



the carbon apparently 



flitution of the plant, while the oxygen is fet at liberty, and efcap 



Qq 



i 



