Miscellanies. 103 



It is remarkable that oxygen deprives fixed oils of their color, and 

 colors volatile oils. 



Experiments of this nature will give rise to the discovery of other 

 products. The oxygenation of the essence of lavender, for exam- 

 ple, affords a compound which, treated with potash, yields an abund- 

 ant salt, unchangeable in the air, and remarkable for its beautiful and 

 easy crystallization. 



4. JVaphtha. — The naphtha of Amiano, when rectified, has a much 

 weaker action on the air than any of the preceding oils. 2.145 c. c. 

 of this naphtha, kept over mercury in a cubic decimetre of air, for one 

 year, did not change its volume. In six years, it had absorbed 9.4 

 centim. cub. of oxygen, and. formed 1.3 c. c. of carbonic acid. The 

 naphtha preserved all its transparency and whiteness ; but it had de- 

 posited on the sides of the receiver, a thin coating of a yellow color, 

 and the mercury was covered with a small quantity of black powder, 

 which had all the character of a sulphuret of mercury. 



The author found that a kilogramme of natural and impure naph- 

 tha, furnished by careful rectification, about 20 grammes of white 

 naphtha, density .755. It has then an elastic force equal to 2.8 inch- 

 es of mercury at 68° F. It begins to boil at 158° F. in a platina 

 crucible, but it acquires by ebullition a constant temperature of 192° 

 F. It dissolves in the cold, in all proportions, in absolute alcohol. 

 One hundred parts of spirit of wine, (density .835,) dissolve only 

 14. Its analysis, by distilling it slowly through incandescent iron 

 turnings in a porcelain tube show it to consist of 



Carbon, ..-.-- 84.65 



Hydrogen, ------ 13.31 



Oxygen, 1.04 



Sulphur, - - - - - - a trace. 



Bib.Univ.Fev. 1822. 



4. On the injurious action of gases on Vegetation ; by M. Ma- 

 CAiRE. — At the suggestion of M. De Candolle, the author performed 

 several experiments to ascertain whether certain gases were equally 

 injurious to plants by day as by night. Agriculturists have sometimes 

 complained that certain manufactures injured the vegetation around 

 them, whereas chemists who have been appealed to, have found from 

 their experiments that the plants were not injured by the action of 

 those gases. From the suspicion that their experiments were always 



Vol. XXIIL— No. 1. 25 



