456 THE POPULAR SCIENCE MONTHLY. 



of dark-green chlorite, from the size of a walnut to that of a fifty-pound 

 shot, within which were one or more crystals of corundum, sometimes 

 blue and white, and, in few instances, of ruby color. None of them 

 were entirely transparent ; none of the geodes had cavities, as is the 

 case in those of quartz formation ; yet the prospect in this direction is 

 most promising. The result thus far, however, is most encouraging 

 in the rock-strata itself, which is the proper gangue of the corundum. 

 With the hundred tons the mine has yielded for abrasive purposes, 

 the workmen have taken from the place of their birth — a solid, undis- 

 turbed matrix of ripidolite — beautiful specimens of the nine corundum 

 gems known by lapidaries by the prefix " Oriental," because of their 

 superior hardness and brilliancy ; and also because those of this char- 

 acter, in lustre and composition, were first brought from the East. 

 These are known by name as Oriental sapphire, ruby, emerald, topaz, 

 asteria, amethyst, chatoyant, girasol, and white or colorless sapphire, 

 this last often used in place of the diamond. The general characteris- 

 tics of these stones, such as color, lustre, hardness, etc., are, by the first 

 lapidaries of this country and Europe, pronounced as not inferior to 

 those of the best localities of the Old World. One of them was sold to 

 a lapidary of Amsterdam, Holland, for $4,000. Others of much beauty 

 have been cut, and are owned in this country and Europe. In this 

 connection it is of value to note that Count Bournon, during his inves- 

 tigations, made a list and analysis of the associate minerals found, in 

 transitu, with the sapphires of Ceylon. Colonel Jenks has had a sim- 

 ilar list and examination made of those found in situ with the gems of 

 his mine. All the minerals found in the Ceylon gem-deposits are 

 found in the North Carolina locality. 



There can be no doubt, therefore, that Colonel Jenks has made 

 the discovery, in America, of the most precious gems next to the 

 diamond, where they have been sought for in vain elsewhere, in a mat- 

 rix of solid rock-formation. We look for further interesting develop- 

 ments at this unique and thus far unparalleled alumina deposit. 



•♦•»• 



ATMOSPHERIC ELECTRICITY AND OZONE: THEIR 

 RELATION TO HEALTH AND DISEASE. 1 



By GEOKGE M. BEAKD, M. D. 



AMONG the published list of questions at the civil service exami- 

 nation of the Board of Health of New York last summer I ob- 

 served this : " What is the composition of pure air ? " 



1 Read before the American Public Health Association, in New York, November 13, 

 1873. It was voted by the Society to publish this paper in their "Transactions," but, 

 through the courtesy of the Secretary, the author is allowed to publish it independently. 



