860 Scien tijic In telligenci — Mineralogy. 



fracture conchoidal. Translucent in thin splinters. Colour black, but 

 by transmitted light reddish-brown : streak cinnamon-brown, lustre 

 between vitreous and resinous, rather brilliant — G. = 1*136, H. = 3. 

 Heated on platinum foil it swells up, burns like pitch, with a 

 disagreeable empyreumatic smell, and a smoky flame, leaving a coal 

 rather difficult to burn, and finally a little gray ash. In a glass 

 tube, yields a yellowish-brown oily product of a nauseous empyreu- 

 matic odour. Insoluble in water, alcohol, ether, caustic, and car- 

 bonated alkalies or dilute acids ; and even strong nitric acid acts 

 slowly. Composition — 



Carbon. Hydrogen. Oxygen. Ash. 



1. 76-74 8-86 10-72 3-68 



2. 77*15 9-05 10-12 3-68 



Affording the ratio CIO H 7 = carbon 77*05, hydrogen 8-99, 

 oxygen 10-28, ash 3*68. Taking the number of atoms of car- 

 bon at 40, which exist in so many resins, the formula becomes 

 C 40 II 28 O 4. It is nearest in composition to amber, which con- 

 tains C 40 H 32 O 4. — (American Journal of Science and Arts, 

 vol. xv., p. 433.) 



5. On Pseudomorphous Crystals of Chloride of Sodium; by 

 G. Wareing Omerod, M.A., F.G.S. — In a paper read before this 

 Society, on 1st December 1852, by Mr Strickland, on pseudomor- 

 phous crystals of chloride of sodium in Keuper Sandstone,* no re- 

 ference is made to prior .observations on the same point. In my 

 paper " On the Principal Geological Features of the Salt-field of 

 Cheshire,"-)* it is stated that " the Waterstone beds (a subdivision 

 of the Keuper) at Holmes Chapel have the same peculiar crystal 

 as those at Lymm, Preston on the Hill, and elsewhere ; " and in a 

 note it is added, " At this place the crystals are of silicate of prot- 

 oxide of iron. This seeming crystal is probably caused by the 

 component matter taking the places of scattered crystals of chloride 

 of sodium, the form of which, both in Cheshire and at Slime Road 

 in Gloucestershire, they have taken, exhibiting, if so, the lowest 

 traces of the salt." To Mr Crace Calvert (Honorary Professor of 

 Chemistry at the Royal Manchester Institution) I was indebted for 

 the examination of this specimen ; and to him any credit for the 

 discovery, as far as relates to Cheshire, is due, he having, on my 

 shewing him the specimens, stated his opinion that the crystals 

 were Pseudomorphic Chloride of Sodium. I had omitted to ask 

 his permission to allow me to mention his name when my paper 

 was read, and it was therefore not then given. This paper was 

 read before the Geological Society 8th March 1848, when specimens 

 were exhibited and a discussion took place, when Professor Buck- 

 land mentioned many localities in which he had observed this 

 pseudomorph, for which he had not hitherto been able to account. 



* Quart. Journ. Geol. Soc. vol. ix., p. 5. t Ibid. vol. iv., p. 273. 



