432 Dr. Schcenbein on the relation of 



1. The epidermis of plants, so far as experiments have 

 been made, is porous, and permits the passage of gases ac- 

 cording to physical laws. 



2. The roots, during the existence of chemical changes in 

 plants, absorb such gases from the soil-fluids as will indi- 

 rectly satisfy the requisitions of the internal atmosphere. 



3. The internal gas of plants fluctuates with the forces 

 which operate on the plant; during the active state of the 

 green vegetable, it resembles a mixture of nitrogen 86*75, 

 oxygen 13*25 per cent., but at night contains more oxygen 

 and a proportion of carbonic acid. 



4. The porosity of the entire plant is fully established by 

 its action on artificial atmospheres. 



Therefore the physical structure of plants is that of a po- 

 rous system subject to the laws of diffusion of gases, and 

 endowed with no vitality other than the power of forming cy- 

 toblasts and arranging cellules after a definite type. 



LXXI. On the relation of Ozone to Hyponitric Acid. 

 By Dr. C. F. Schosnbein *. 



nPHE chemical effects produced by atmospheric air charged 

 -*- with hyponitric acid (N0 4 ) are so very like those 

 caused by ozonized air, that some chemists are inclined to 

 consider hyponitric acid as identical with ozone. Both de- 

 compose iodide of potassium, transform the yellow prussiate 

 of potash into the red one, decompose sulphuretted hydrogen, 

 colour blue the resin of guaiacum, destroy organic colouring 

 matters, polarize negatively platinum, &c. 



In spite of the similarity of chemical properties exhibited 

 by ozone and hyponitric acid, those substances are in many 

 other respects so entirely different that their being identical 

 cannot be thought of: thus ozone is produced under circum- 

 stances in which an essential constituent part of hyponitric 

 acid is absent, namely nitrogen. The analogy existing be- 

 tween the chemical action of the two bodies mentioned appears 

 however so striking, that we can hardly help suspecting some 

 connexion to exist between them, and with the view of ascer- 

 taining that connexion I have of late made many experiments, 

 the account of which will form the substance of this paper. 



The results obtained from these researches are, in my opi- 

 nion, such as to speak strongly in favour of my conjecture 

 that there exists a compound composed of NO a + H0 2 . It 



* Communicated by the Chemical Society; having been read November 

 3, 1845. 



