428 Mr. Seybcrt's Analyses of the [June, 



nature.* Previous to that period, the mineralogists in the 

 United States supposed it to be Corundum. The late celebrated 

 crystallographer observes, " La cymophane des Etats Unis a 

 d'abord ete prise pour une variete de corindon. EfFectivement 

 elle se rapproche de ce mineral par sa durete, par sa pesanteur 

 specifique, et meme par le resultat de son analyse, qui a donne 

 environ 72 parties d'alumine but 100, avec 18 de silice, et 6 de 

 chaux."f 1 was anxious to examine the cymophane found at 

 Haddam, especially as M. Hauy does not name the author of 

 the analysis he quotes. The specimen used for my experiments 

 was of a pale green colour. It did not present any of the 

 chatoyant appearance so remarkable in the variety from Brazil, 

 and some specimens from Saratoga in New York, where it was 

 lately discovered by Dr. Steel. Its specific gravity, by two 

 trials, was 3*508 and 3 # 597. It is not magnetic, and before the 

 blowpipe it is infusible. For a further description of the physical 

 characters of this mineral, I refer to Hauy and Cleav eland. 



Three grammes of the mineral were examined under the 

 impression that Prof. Klaproth's analysis was accurately made. 

 It was decomposed in the usual manner with four parts of caustic 

 potash, and subsequently treated with diluted muriatic acid ; 

 but the solution was imperfect. The insoluble matter was col- 

 lected on a filter, and it amounted to 25 or 30 per 100. It was 

 repeatedly acted on in the same way, and each time it dimi- 

 nished in quantity, until the fourth experiment. It then weighed 

 about fifteen-hundredths, and thereafter resisted all further 

 efforts to render it soluble by these means. This residue was 

 then boiled in concentrated sulphuric and muriatic acids, but 

 neither of them dissolved more than one-third of it. These 

 solutions were tested by different reagents, and greatly to my 

 surprise, the addition of subcarbonate of ammonia occasioned a 

 floculent precipitate, which entirely redissolved in an excess of 

 the alkaline subcarbonate. I immediately suspected the pre- 

 sence of glucina, but was much at a loss to explain its insolubi- 

 lity, until I observed Berzelius's analysis of the euclase,^; in 

 which he met with a compound of glucina and oxide of tin that 

 obstinately resisted acids. He also met with refractory combi- 

 nations of this earth and the oxides of manganese and cerium. 

 I next endeavoured to dissolve the compound by the acid sul- 

 phate of potash; but this method did not succeed. I was not 

 more successful with the nitric and nitromuriatic acids ; nor 

 could it be dissolved by means of boric acid. Berzelius having 

 discovered columbium in the gangue of the cymophane from 

 Haddam, the insoluble residue was tested for the oxide of that 

 metal, but all my attempts were fruitless. At length, I sup- 



* Annales du Museum d'Histoire Naturelle, tome xviii. p. 57. 

 ■j- Traite de Mineralogie, second edition, vol. ii. p. 309. 

 j Nouveau Systeme de Mineralogie, p. 2S9. 





