D. CHEMISTRY AND METALLURGY. 217 



of a great variety of very interesting compounds, and it 

 yields, as before stated, mellilotic acid, which in its turn 

 yields coumarin. It is mellilotol, and not coumarin, which 

 is the cause of the odor of new-mown hay and of that of the 

 flowers of the Mellilotus. 1 A, July 16, 25. 



MANUFACTURE OF ARTIFICIAL VANILLA. 



It is not long since Messrs. Tiemann and Haarmann, stu- 

 dents of Dr. Hofmann, of Berlin, made the discovery that 

 vanillin, or the aromatic principle of the vanilla bean, can 

 be obtained from the sap of the pine. These gentlemen have 

 now completed their operations for going into the manufact- 

 ure of the article on a large scale, as they find that the sap 

 of an ordinary tree will furnish vanillin of the value of $20, 

 without in the least injuring the wood for timber. Dr. Hof- 

 mann, in communicating these facts to the Academy of Sci- 

 ences of Paris, remarks that this is the second vegetable prod- 

 uct manufactured by purely chemical methods. 12 A, Sep- 

 tember 24, 1874, 427. 



HYDROGENIZED IRON. 



Cailletet states that in his experiments on the passage, 

 at ordinary temperatures, of hydrogen through iron, he has 

 found that on allowing sulphuric acid to act upon a plate 

 of iron, the hydrogen is, in part, absorbed by the metal, and 

 that, by employing a system formed of two plates of iron 

 soldered side to side, he finds the tension of the gas which 

 accumulates in the apparatus is equal to a column of mer- 

 cury 0.35 millimeter high. As the result of his investiga- 

 tions into this combination of iron and hj^drogen, he says 

 that this iron gives up, under water or other liquid, nume- 

 rous bubbles of a gas which is pure hydrogen. In the open 

 air the galvanic iron loses only a part of the hydrogen 

 which it has occluded. When a piece of hydrogenized iron 

 is brought near a burning body the hydrogen is rapidly dis- 

 engaged, and the metal is surrounded by a light-blue flame. 

 When the iron has lost by heat the hydrogen which it con- 

 tained, one can not restore that gas to it. Employing a 

 piece of iron that had been so heated as a negative elec- 

 trode, Professor Cailletet found that the water is decom- 

 posed and the hydrogen disengaged as usual in abundance ; 



K 



