D. CHEMISTRY AND METALLURGY. 205 



sity, announced that he had obtained a double series of no 

 less than seven metameric bodies among the ammonio-cobalt 

 compounds. Of these bodies he himself discovered all but 

 the first one, which has been known for some time. All of 

 these bodies are crystalline, remarkably stable, and very beau- 

 tiful. As the discovery is one of such great interest, the form- 

 ulae are appended. In the first limb of each equation is given 

 the rational formula, indicating the structure of the com- 

 pound; in the second limb the resulting empirical formula is 

 placed, in which the metamerism, or similar elementary com- 

 position of the bodies, becomes evident. In these formulae 

 Co stands for cobalt, A is a condensed expression for ammo- 

 nia, and X represents nitroxyl, or the group of atoms N0 2 : 



1. (Co 2 A 4 X 8 )(Co 2 A 8 X 4 ) =2Co 2 A 6 X 6 . 



2. (Co 2 A 4 X 8 ) 3 (Co 2 A 12 ) =4 Co 2 A 6 X 6 . 



3. (Co 2 A 4 X 8 ) 2 (Co 2 A 10 X 2 )=3 Co 2 A 6 X 6 . 



4. (Co 2 X 12 )(Co 2 A 8 X 4 ) = 4 Co 2 A 6 X 6 . 



5. (Co 2 X 12 )(Co 2 A 12 ) =2 Co 2 A 6 X 6 . 



6. (Co 2 X 12 ) 2 (Co 2 A 10 X 6 ) 2 =5 Co 2 A 6 X c . 



7. Co 2 A 6 X 6 , a compound long known, which seems 



to be really the lowest term in this double series. It will 

 be seen that all the others are multiples of this; in bodies 1, 

 2, and 3, the group of atoms Co 2 A 4 X 8 occurs, while num- 

 bers 4, 5, and 6 all contain another group, Co 2 X ]2 . The struct- 

 ure of the 7th compound has not yet been clearly made out. 

 Prof. F. W. Clarke. 



ARTIFICIAL VANILLA. 



Tiemann and Ilaarmann, on adding a ferment, in emulsion, 

 to the coniferin extract of cambium of coniferous trees, as- 

 certained that coniferine is separated into glucose and into a 

 substance crystallizing into beautiful prisms, melting at 75, 

 and having for the formula C 10 II 12 O 3 . This body, under the 

 influence of oxidizing agents, is transformed into another 

 crystalline body, with the flavor and odor of vanilla. This 

 lias precisely the same formula (C 8 H 8 3 ) as the aromatio 

 matter extracted from vanilla, and presents the same reac- 

 tions with it. It is, therefore, not at all impossible that in 

 this we have another of the applications of organic chemistry 

 to the arts by which quite an expensive substance may be 



