314 EIGHTH REPORT 1838. 



Formula adopted. 



Mesotype SAS + NaSa + SHO 



Prehnite 3 AS + Co^Sg + 2HO 



Steatite A S2 + 2 Ma Sg + 4 H O 



Chabasie 3 A S2 + Ca S3 + 6 H O 



Analcime 3 A Sg + Na 83 + 2 H O 



Harmotome 4 A Sg + B« S4 + 6 H O 



Killinite 8AS2+KS4 + 3HO 



Various uniaxaland biaxal micas, and some metallic sulphurets 

 and sulpho-salts, have also been attempted by way of double 

 decomposition. 



The substances to be tried, when mixed and covered with 

 water, are sealed in Bohemian glass tubes, numbered and ex- 

 posed to steam in a box between two low-pressure boilers, in 

 one or the other of which steam is always up. 



Specimens of peat, of lignin, of coal, and other analogous 

 organic bodies, have also been exposed in various ways, in the 

 expectation that some light may be thrown upon the formation 

 of coal and bitumens ; and various supposed insoluble crystal- 

 lized native minerals have also been exposed immersed in boiling 

 water, in order to determine what its action, if any, may be on 

 their crystals, and what effect may result from the dissolved mat- 

 ter. Various woods have been placed in contact with gelatinized 

 silex and its solutions, in the hope of slowly forming silicifica- 

 tions similar to those from Antigua, &c. 



These experiments, it is conceived, will connect themselves 

 in a very interesting point of view with those in progress under 

 Mr. Vernon Harcourt's superintendence upon the action of a 

 much higher but indefinite temperature upon mineral bodies. 

 There is every probability that very many of the minerals in 

 the crust of the earth, especially the crystalHzed ones, have 

 been formed at a comparatively low temperature. Quartz is 

 daily deposited from the water of the Geysers, and has been 

 found in a soft and pasty state elsewhere. — {Betidant Traiie.) 

 Malachite has been found in a similar state. Vauquelin found 

 stalactitic quartz, {Ann. de CJmn. xxi.). Crystals of quartz have 

 been found in the United States, containing anthracite, and 

 one containing a liquid with a piece of coal floating in it ; and 

 Mr. Haig found hard crystals of quartz in a bottle of Saratoga 

 water, which had stood many years, [Quart. Jour. xv.). The 

 globules of fluid found in amethyst, chrysoberyl, topaz, fluor 

 spar, &c. &c., a fluid found by Dr. Brewster to be volatile at 

 75° Fahr., {Edin. PJnl. Jour.) ; the existence of bitumen in 



I 



