138 



Microscopical Objects in the Potash Salts of Stassfurt. 

 Communicated by Herr Weissflog. 



If the red Carnallit of Stassfurt be dissolved in water, there 

 remains a bulky residuum (amounting, however, only to 0-075 per 

 cent, of the whole) which, treated chemically, is found to consist of 

 the following ingredients, viz. : — 



94-5 per cent, of oxide of iron. 



0"4 ,, alumina. 



1'9 „ silica. 



3-2 „ matter destructible in a red heat. 



Of this last 2-3 parts are soluble in alcohol. 



When heated to redness this residuum emits an empyreumatic 

 odour, and assumes a black metallic hue, which, during the process 

 of cooling, passes again to red, and in consequence of its conver- 

 sion into black oxide becomes slightly magnetic. The Carnallit 

 from Maman, in Persia, behaves in a similar manner. 



On placingthis residuum under the microscope there is seen such 

 beauty of form and gorgeousness of colouring as are scarcely to be 

 found, even in Aventurine. Magnificent crystals develope them- 

 selves, interwoven with which are spongelike fibrous organic re- 

 mains. Much has already been written about these microscopic 

 structures, and attention has been drawn to them by descriptions 

 and figures — A. Goebel, Melanges physiques et chimiques de 

 I'Acad., de S. Petersbourg, vi., 413 ; T. Tritsche in the same, 

 463; F. Bischoff, the Eock Salt Works of Stassfurt, 31; T. 

 Cohn in Schultze's Archiv. fiir Microscopische Anatomic, Bonn, ' 

 1867, p. 4. — but neither description nor figure can give the same 

 marvellous impression as is conveyed by the microscope. 



First there meets the eye six-sided rhombic plates of peroxide 

 of iron, of a yellow hue, but passing through every gradation of 

 colouring into deep blood red. These plates gradually thin out 

 into elongated bars, or rods, which, even under the highest 

 powers, reach a magnitude of at most nr.-oinr P^^'* ^f a line, and 

 which traverse the entire texture in every direction. At one time 

 they were supposed to be the remains of an a]ga (Hygrocrocis)^ but 

 there is no doubt of their being of the same nature as the crystals, 

 for they remain of the same colour and shape when exposed to a 



