1840.] On the Advancement of Geological Science in India. 81 



posed." It might have disintegrated in structure, but decomposition 

 is impossible, because that would have destroyed the fissile structure, 

 Disintporation, and decomposition, are two very different operations— the 

 one mechanical, the other chemical. An instance of disintegrntion 

 without decomposition is seen in the masses of quartz rock in India, 

 which are always disintegrated, but never decomposed. In India, a 

 piece of quartz larger than the cube of one inch can never be found 

 without cracks, but it never presents any appearance of decomposition. 

 If we heat a piece of glass, and plunge it in cold water it fails to pow* 

 der or cracks to pieces, it is disintegrated, but not decomposed. Each 

 particle is still a silicate of soda. In the same way most crystalline 

 particles of disintegrated rocks will be found to have a porphyritic or a 

 granular, aggregated structure. 



In collecting information on Indian geology, the greatest difficulty 

 appears to be, that the number of people, who have time and opportu* 

 nities for the pursuit, are very few; but if every one who chooses to at- 

 tend to the subject, would apply himself, to compile accurate descrip- 

 tions of the part of the country, adjacent to their stations, we should 

 soon have a valuable collection of the geology of isolated spots, which 

 those who are employed by Government in these scientific pursuits 

 -could soon and easily connect together. In the furtherance of this 

 end, a geological society would be of the utmost advantage — they would 

 receive and assist in the discussion of such information, compare speci- 

 mens, have chemical examinations made, and afford that information 

 and directions to tyros which no printed work on the subject could 

 give,— and particularly any individual of the society who has had the 

 advantage of studying the science practically in Europe, could then 

 afford the most valuable information, in identifying minerals with those 

 of Europe.* 



In the study of the primary rocks, we cannot advance one step 

 without the aid of mineralogy, but this science unfortunately is 

 fitill in its infancy, and even the principles on which it is to be baseci 

 are not yet agreed on. Mobs, in his system, considers the crystalline 

 form alone, and rejects all minerals which are amorphous. Dr. Thomson, 



* This Journal is published by a Society, of the prototype of which it was declared by 

 Sir William Jones that " the bounds of its investigation will be the geographical limits 

 of Asia ; and within these limits its enquiries will be extended to whatever is perform- 

 ed by man or produced hy Nature.''* The sub-division of scientific labour does not seem 

 called for here as in Europe, where there are so many labourers in the field ; so that 

 a Society for the cultivation of each science is not desirable; and the Meetings of the 

 Madras Literary Society may be made the place of reunion for all geologists, and 

 its already large mineralogical cabinet the receptacle for specimens. Our correspondent is 

 reminded that the Society will be thankful for specimens illustrative of his remarks, 

 which are usually transmitted by Authors,— -Ec^e^or. 



