Minerals, Etc.—Specimens have been received from the following correspondents, and examined, with the results stated:
S. (New Orleans.)—The powder consists of a mixture of zinc oxide and finely powdered resin. A quantitative analysis would be necessary to determine the proportions.
Any numbers of the Scientific American Supplement referred to in these columns may be had at this office. Price 10 cents each.
| COMMUNICATIONS RECEIVED. |
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Life Preserving Stone. By J. D. W. On Ventilation. By D. W. What is Mental Action? By N. K. Panama Railroad or Canal. By G. R. P. A Problem. By K. On the Gary Motor. By G. F. M. Magnetic Motor. By G. W. W., W. A. A., G. H. F. House Warming. By H. B. F. The Injector. By M. A. B. Columbus' Problem; Cure for Diphtheria; The Mullein Cure for Consumption. By R. W. L. A Visit to Tula. By L. R. On Vacuum in Pumps and the Atwood Machine. By P. J. D. On the Patent Bill. By R. |
[OFFICIAL.]
INDEX OF INVENTIONS
FOR WHICH
Letters Patent of the United States were Granted in the Week Ending
February 18, 1879,
AND EACH BEARING THAT DATE.