Mineralogy, Medicine, S)C. 193 



compound of nitric acid, oxide of zinc, and potash : and if the 

 boiling- was continued for some time, a second triple salt will 

 form, which is a compound of nitric acid, oxide of zinc, and 

 ammonia. — I remain, Sfc. 



John Thomas Cooper, 

 Teacher of Chemistry, and Analytical Mineralogy* 



III. Natural History. 



§ MiNKRALOGY, MeDICINE, ^C. 



1. Native Iron — " A mass of native iron, weighing upwards 

 of three thousand pounds, was discovered several years ago on 

 the banks of Red River in Louisiana, and is now in the col- 

 lection of the Historical Society in the New York Institution. 

 Its shape is irregular, inclining to oviform ; its surface deeply 

 indented, and covered by an oxide of iron, and it is much 

 broader at the bottom, -where it has rested on the earth, than 

 at the top, inclining somewhat in the manner of a cone. By 

 several experiments which have been made upon different pieces 

 of il, there appears to be a want of uniformity in its quality, 

 some parts being very malleable and ductile, while others pos- 

 sess nearly the hardness of steel. It is susceptible of the 

 highest polish, and is said to contain some nickel. Colonel 

 Gibbs, through whose munificence this rare specimen of the 

 physical productions of our country has been placed among the 

 collections of the Historical Society, has discovered in its in- 

 terior, octohedral crystals of singular beauty, some of which are 

 half an inch in length, and striated. This mass of iron was 

 found about one hundred miles above Natchitoches on Red 

 River, on one of those rich and extensive prairies so common to 

 that part of the country, and about twelve miles from the banks of 

 the river. Other pieces have been found in that neighbourhood, 

 and if reliance is to be placed on the information from travellers in 

 that quarter, very large masses of native iron now exist there." 

 •^Schooler oft. Lead Mines of Missouri, p, 217. 



2. Supposed Meteoric Iron at Aix-la-Chapelle. — A mass of 

 ferruginous matter was observed, in the year 1762, whilst re- 

 VoL. IX. O 



