Intelligence and Miscellaneous Articles. 147 



John Ayrton Paris. The second blunder occurs in mentioning a 

 quack remedy, which is described as -Mhite head's essence of mus- 

 tard. 



JET DISCOVERED IN WIGTONSHIRE. 



Beautiful specimens of this mineral have been found between a bed 

 of peat and mellow clay, in the peninsula formed by Loch Ryan and 

 the Irish Channel, by SirAndrew Agnew. — Jameson s Edinb. Journ. 



Jan. 1827. 



ORIGIX OF THE DIAMOND. 



In the Philosophical Magazine for November 1826, is inserted an 

 article from the Asiatic Researches, vol. xv., " On the Diamond 

 Mines of Southern India," by the late Mr. Voysey, Geologist to the 

 Trigonometrical Survey of India. The question, as to the proper ma- 

 trix of the diamond, being one of great interest in the inquiry con- 

 cerning the periods in the physical history of the earth, at which the 

 various forms of carbon were respectively first produced, and also 

 in that relating to the natural process by which this gem was form- 

 ed, and as the paper alluded to appears to be less decisive on the 

 subject than could be wished, it may be useful to future inquirers 

 to make a iew remarks on Mr. Voysey 's statements. 



The description given in this paper of the constitution of the 

 Nalla Malla mountains is somewhat indecisive and confused ; and 

 does not afford the means of determining, with precision, to what 

 formation the sandstone-breccia belongs, which is stated to be the 

 matrix of the diamonds. But it would appear that this range consists 

 of transition strata, intersected or overlaid in some places, by trap- 

 rocks; the breccia, of course, belonging to the former class. The 

 imperfect nature of this description, however, is rather to be attri- 

 buted to the existing deficiency of correct general views on the ge- 

 ology of India, than to any want of accuracy or of knowledge in 

 the observer. 



But an aggregate rock, consisting, it is stated, of jasper, quartz, 

 chalcedony, and hornstone, cemented together by a quartzose paste, 

 and passing into a pudding-stone composed of rounded pebbles of 

 the same substances, cemented by an argillo-calcareous earth, can- 

 not be the matrix of the diamond, as Mr. Voysey supposes. The 

 diamonds it contains, like the other minerals of which it is consti- 

 tuted, must have existed previous to its consolidation ; and it is 

 possible, that, also like them, they were derived from the destruction 

 of some older rocks. The matrix of the Brazilian diamond, we have 

 some reason to believe, from a specimen not long since described 

 by Mr. Heuland, (Geol. Trans. 2d series, vol. i. p. 419,) is a brown 

 iron-stone, which occurs in thick veins or beds resting on chlorite 

 slate ; and from the disintegration of which and the accompanying 

 rocks, the materials of the alluvial conglomerate called cascalhao, 

 from wiiich the diamonds of Brazil are usually obtained, may be 

 (Supposed to have resulted. 



Professor Jameson, a few years since, expressed an opinion, that 

 the diamond, being a form of pure carbon, might have been origi- 

 nally secreted from the juices of some plant, in a manner similar to 



U 2 that 



