60 On the Action of Potash upon Cholesterine. 



The crystals are often so much compressed as to resemble four 

 or six-sided tablas. Their color is usually white, and they are 

 either translucent or opaque. The opaque crystals exhibit the 

 pearly lustre in the highest perfection. 



Besides the minerals already noticed, there have been found at 

 Bergen Hill specimens of crystallized iron pyrites and galena, 

 besides calcareous spar exhibiting various crystalline forms. 

 Among these may be mentioned the metastatique and the ca- 

 boide of Haiiy. The latter, as I have already observed, may 

 easily be mistaken for the primary of chabazite. In other cases 

 these crystals are modified so as to resemble some of the forms 

 of datholite ; and in a few instances they even have the high 

 lustre of this mineral. I have indeed thought that they might 

 be pseudomorphs. Several specimens of this kind, which I took 

 for chabazite and datholite, were dissolved with effervescence in 



* 



dilute muriatic acid. I will only add, that at Bound Brook and 

 Paterson, agate balls occur in the trap. These are usually quite 

 small and unimportant, but beautiful specimens, two or three 

 inches in diameter, were several years since obtained from the 

 latter locality. 



Art. VIII. — A short Notice of the Action of Potash upon Choles- 

 terine; by J. Lawrence Smith, M. D., of Charleston, S. C. 



For some reasons we would be induced to place cholesterine 

 among the fatty bodies, but from many of its characters, it would 

 appear certainly not to belong to this class of bodies. The most 

 important distinctions between these two bodies are — first, the 

 want of action of a solution of potash upon cholesterine ; and 

 secondly, its high point of fusion, which is 298° Fah .* 



Another difference which I am able to point out is, that cho- 

 lesterine is heavier than water, whereas the fats are lighter. It 

 will be found in works on chemistry, that cholesterine is lighter 

 than water, and I attribute this to the fact, that the substance, as 

 it crystallizes out of alcohol, was found to float on the surface 

 of water ; but this is owing to the air adhering to the crystals. 

 To show that it is heavier, all that is necessary to be done, is to 



* The melting point of most of the fats is below 140° 



. 



