33* Intelligence and Miscellaneous Articles. 



ACTION OF ^TIIER ON INDIGO. — BY M. VOGEL. 



I had more than once remarked by chance that when the vapour 

 of aether is passed into a solution of indigo in sulphuric acid largely 

 diluted with water, it was decolorated. This effect is produced 

 more readily when the aether is heated to ebullition in a matrass 

 furnished with a bent tube which is immersed in the solution of 

 indigo ; and if the matrass be suddenly cooled, so that the solution 

 of indigo rises in the tube and passes into the matrass by the 

 pressure of the air. When I attempted on another occasion to de- 

 colorate indigo by means of aether which had been rectified over pot- 

 ash, I could not so readily effect it, which induced me to believe 

 that the impure aether, which contained sweet oil of wine, or pro- 

 bably aldehyd, was more fit for the decoloration of indigo than 

 pure aether. 



To satisfy myself, I added to a solution of indigo in a bottle a 

 few drops of aldehyd, and I remarked that the liquor, at first of an 

 emerald green colour, became of a pale green, and after some days 

 became of a yellowish brown. As the aldehyd which I employed 

 contained alcohol, it not having been rectified, I afterwards made use 

 of pure aldehyd, which was separated from its ci-ystalline com- 

 bination by ammonia : a few drops of this pure aldehyd were 

 sufficient to destroy the blue colour of indigo in a very short time, 

 the solution becoming of a straw yellow. When the aldehyd was 

 evaporated by heat, the blue colour could not be made to reappear. 

 The addition of potash, and of red oxide of mercury, were not capable 

 of restoring the blue colour. On evaporating the decolorated liquor 

 there remained a brown substance analogous to ulmin. This de- 

 coloration of indigo by aldehyd occurs only when the indigo is 

 dissolved in sulphuric acid. Indigo in fine powder, diffused through 

 water, undergoes no change by aldehyd : neither the tincture of 

 litmus, nor the spirituous tinctures of cochineal or turmeric, are de- 

 colorated by aldehyd. — Journal de Pharm. Mars 1839. 



EFFECTS OF MUSHROOMS ON THE AIR. 



According to Dr. Mariet mushrooms produce very different effects 

 upon atmospheric air, from those occasioned by green plants under 

 the same circumstances ; the air is promptly vitiated, both by 

 absorbing oxygen to form carbonic acid at the expense of the vegetable 

 carbon, or by the evolution of cai'bonic acid immediately formed ; the 

 effects appear to be the same both day and night. 



If fresh mushrooms be kept in an atmosphere of pure oxygen gas, 

 a large proportion of it disappears in a few hours. One portion 

 combines with the carbon of the vegetable to form carbonic acid, and 

 another is fixed in the plant, and is replaced by azotic gas disengaged 

 from the mushrooms. 



When fresh mushrooms are placed for some hours in an atmo- 

 sphere of azotic gas, they produce but little effect upon it. A small 

 quantity of carbonic acid is disengaged, and in some cases a little 

 azote is absorbed. — Ibid, 



