50 Mr Haidinger on Botryogene. 



Fig. 5, which is in the cabinet of Mr Allan, in fact more nearly 

 resembles a bunch of grapes than any thing else I ever saw 

 in the mineral kingdom. The trivial name botryogene, from 

 /3orgi)c, a bunch of grapes, and yr/vopai, I produce, alludes 

 to the tendency of this salt to produce such imitative shapes. 

 It is the more necessary to give it a name, as it has not been 

 provided as yet even with a chemical denomination. 



It occurs in the great copper mine at Fahlun, in Sweden, 

 in the level called Mellanrums-Ort, as a coating on gypsum or 

 iron-pyrites, along with Epsom-salt, sulphate of the peroxide 

 of iron with excess of base, and the common green vitriol. 

 When exposed to a moist atmosphere, it becomes covered with 

 a dirty yellowish powder. It remains unchanged in a dry at- 

 mosphere. 



Before the blowpipe it intumesces, and gives off water in 

 the glass tube, leaving a reddish-yellow earth behind, which, 

 according to the flame employed, may be changed into pro- 

 toxide or peroxide of iron. With salt of phosphorus it yields 

 a red glass, which loses its colour on cooling. Boiling water 

 dissolves part of it, leaving a yellow ochre, which, therefore, 

 is an integral portion of the mixture. The solution, nitric 

 acid being added to it, may be precipitated by muriate of ba- 

 ryta, but not by nitrate of silver. Caustic ammonia, with 

 which the salt is digested in a stopped bottle, takes away all 

 the acid, and leaves the iron in the shape of a black powder, 

 slightly greenish. The iron, therefore, is contained in the 

 salt, not as a pure oxide, but as a compound of the protoxide 

 and the peroxide, which is black when pure, and produces red 

 solutions. 



The following are the results of three analyses : — 

 Persulphate of iron with excess of I. II. III. 



base, - 6.77 6.85"* 



Bisulphate of the protoxide and pe- >- 48.3 



roxide of iron, - - 35.85 39.92 3 



Sulphate of magnesia, - , 26.88 17.10 20.8 



Sulphate of lime, - - 2.22 6.71 0.0 



Water and loss, - - - 28.28 31.42 30.9 

 The second analysis is the most correct as to the water. 

 Berzelius conceives the water in the sulphate of magnesia to 

 contain five times the quantity of oxygen contained in the base, 



