60 Dr. Clarke on Arragonite. [July, 



and both being reducible to lime by the blowpipe. One of 

 those dealers, visiting himself the part of Spain where arragonite 

 is found, afterwards imported into this country, a number of 

 sub-varieties, differing in their form and structure from the large 

 hexagonal crystals of this substance. We then became 

 acquainted with plumose arragonite, spheroidal arragonite, and 

 even earthy arragonite. Presently all those stalactites from the 

 mines of Styria, and other places, which had been placed in 

 cabinets among the carbonates of lime, under the name of Jios 

 Jerri, because found in iron mines, being found to possess the 

 characters of arragonite, were added to the list of the sub-varie- 

 ties of this mineral under the name of coralloidal arragonite. To 

 this great increase in the number of the sub-varieties of arragon- 

 ite may, perhaps, be owing the observation of Brongniart, that it 

 appeared to him to be impossible to fix any precise boundary 

 between arragonite and the other varieties of carbonate of lime.* 

 The best chemists are, however, unanimous in their opinions as to 

 the propriety of distinguishing these minerals from each other. 

 In the year 1814, our Professor of Chemistry, the celebrated 

 Tennant, discovered arragonite among the stalactites that had 

 been brought from the cavern of Antiparos, in Greece ; and 

 soon afterwards, it was proved by Mr. Holme, that the stalac- 

 tites, from the same cavern, which Mr. Hawkins had presented 

 to the Woodwardian collection, were also of arragonite. The 

 remarkable discovery of Professor Tennant (while it proved, 

 contrary to the opinion of the most eminent mineralogists and 

 chemists of the day, that arragonite might result from a simulta- 

 neous process with that by which calcareous alabaster is depo- 

 sited, and that the stalactites, both of one and of the other, 

 might be found suspended from the roof, or investing the sides, 

 of the same cavern), tended to throw great light upon the 

 natural history of this mineral. It strengthens the opinion, that 

 whatever may be the distinction between the two minerals, their 

 difference is not of a chemical nature. It also proves, that 

 masses of equal magnitude with any masses that have hitherto 

 been discovered of calcareous alabaster may also reasonably be 

 expected in arragonite. Consequently, it may be considered, as 

 having, as it were, opened the door for the discovery made by 

 Mr. Belzoni, as far as it affects the science of mineralogy ; 

 because, by anticipation, it established the probability that 

 masses of arragonite equalling in magnitude even that of the 

 Theban Soros, would afterwards be recognized as of genuine 

 arragonite ; and in the inspection of the substance of this Soros, 

 notwithstanding its enormous size, it is evident that it was ori- 

 ginally deposited by the stalactite process. This appears in the 

 variety of translucid zones and layers which it exhibits, and 



* " II ne nous a pas paru possible d'assigner des limites precises entre l'arragonite et 

 les autres varietes de chaux carbonatee."— (Traite de Mineralogie, torn. i. p. 220. 

 Paris, 1807.) 



