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On the Forms assumed by Uncrystallized Mineral Substances, 

 such as the Ocellated Stones of Dendera in Upper Egypt, 

 the Stones of Imatra, eye. By M. Ehrenberg.* 



The ancients have often spoken of the sports or anomalies of nature 

 (lusus naturcej as so many attempts to produce all kinds of forms 

 in earthy and stony substances. In consequence, they have not se- 

 parated true petrifactions and organized fossil remains from inorganic 

 formations, and have considered the whole as the incomplete attempts 

 at development made by a formative earth acting as a matrix. Our 

 notions are now altered, yet naturalists still speak of the sports of 

 nature both in regard to inorganic and organic matters ; and the col- 

 lectors of curiosities continue to store up in their cabinets inorganic 

 forms of this nature as remarkable objects, and deserving of being 

 viewed with interest. It may be admitted that they are often deserving 

 of this attention ; but at the same time they are often nothing more than 

 stony formations, to which friction, fracture, splitting, or some other in- 

 ternal mechanical action, has given a singular aspect which can be of no 

 interest to science ; or rather it may be said that the caprice or imagina- 

 tion of the collector has ascribed to them relations and analogies of 

 form, just as frequently happens with figures representing clouds, in 

 which every one, according to his fancy, thinks he can discern a multi- 

 tude of resemblances to known objects. 



Among inorganic forms of the highest scientific interest, which have 

 excited attention from the most ancient date, and more than ever in re- 

 cent times, arc those resulting from crystallization, which are grouped 

 with mathematical regularity, perfectly determinate in their angles, and 

 produced by an active mode of formation. Besides this, it has been 

 ascertained, that this remarkable exterior appearance depended on the 

 laws of their internal formation, which enable us to explain gcncrically 

 and positively the most varied changes of form, and to recognise the ori- 

 ginal type of structure even in an amorphous fragment. 



Besides crystalline forms, a series of others exist, alwajs reproduced 

 in the same shape, some of which have not been made the subject of obser- 

 vation, while others have been but imperfectly studied. They are, how- 

 ever, possessed of great scientific interest, and are frequently met with 

 in nature. I am about to speak, says M. Ehrenberg, of the ocel- 

 lated stones or stones a lunette of Egypt, which are regular, oficn a foot 

 in size, and which, along with Ur Hemprich, I discovered, in 1821, in in- 

 calculable numbers in the desert of Dendera, Upper Egyj>t,t where they 



* This memoir was read to the Royal Academy of Berlin, 29:h June 1840. 

 t About eight years ago we received from the Rev. Vere Monro some remark- 

 able anuular-discoid morjiholites brought by him from Egy[ t. -Edit. 



