Intelligence and Miscellaneous Articles. 3 1 9 



which he had observed, with the help of a microscope, in earthy and 

 soft minerals. 



*' An exact microscopical analysis, several times repeated, of up- 

 wards of a hundred minerals, of different groups, showed me — 



" 1. That chalk, both white and coloured, consists of small ellip- 

 tical bodies, flat and symmetrical, or their fragments, — bodies which 

 vary in magnitude from -^^ to t^^ lin., and are formed of concen- 

 tric articulated rings. 



** 2. That the Calcaire cotonneux, or Bergmilck, and the Calcaire 

 iricrustantj or Kalkguhre, consist of small articulated needles, straight 

 and rigid, often collected together in fascicles, and in which the 

 articulations or grains (elementary particles, not atoms,) exhibit a 

 tendency to form a spiral. 



**3. That the porcelain earth of the Aue and Calle (true Ka- 

 olin, in which are likewise found fragments of feldspath,) consists 

 also of round bodies, larger, to the size of ^V lin*. regular, similar 

 to those of the chalk, but discoidal or in their fragments. 



"4. That the Meerschaum and Bergleder consist of threads or 

 very finely articulated nets, more or less interlaced or felted 

 (Jeutres) and flexible, the articulations of which are constantly of a 

 uniform size. 



" 5. That the mixed earths or rocks, as the potters' clay, the 

 glaises, the pseudo-meerschaum, also exhibit, on microscopical ana- 

 lysis, very curious facts of the same kind. 



*' 6. That even crystallized quartz and mica, as well as some other 

 minerals, present a granulated appearance of great regularity, either 

 without their outer surface of fracture undergoing any previous pre- 

 paration, or after having been warmed or heated to redness. 



"7. That by artificial means, such as a red heat, siliceous and 

 argillaceous substances may be transformed (by the polarization of 

 the elementary parts, which may be compared to the cellular tissue 

 of plants,) into a tissue or felt, composed of articulated spiculae. 

 Nature exhibits this effect in the Meerschaum, and art produces it 

 in the manufactory of porcelain and the slag of intense furnaces." 

 —VlnstituU^o. 194. 



PYROPHORI OF EASY PREPARATION. 

 It is well known that when 2^ parts of pure tartaric acid, de- 

 prived of its water of crystallization, are quickly mixed in a dry 

 capsule with 8 parts of peroxide of lead, perfectly dry and reduced 

 to powder, ignition very soon occurs throughout the mass, which is 

 very vivid and of long duration. This fact, first mentioned by 

 Walker, would lead to the supposition that other organic substances 

 would undergo similar reaction with peroxyd of lead ; and this has 

 been verified by the experiments of M. Bcetliger. On experiment- 

 ing with the oxalic and citric acids, he found that the action of the 

 former on the peroxyd of lead was more rapid, and perhaps stronger, 

 than that of tartaric acid ; while that of citric acid was rather weaker. 

 Thus, on mixing together 5\ parts of peroxyd of lead, and 1 part of 

 oxalic acid dried in hot air, or containing 19 per cent, of water. 



