of mining accidents, such as his lamp with him without danger; and to retain the free atmospheres, affords a supply capable of lasting half an occur almost weekly in the Pennsylvania mining. districts, use of hisarms. Of the competing apparatus sent in, the hour. The air, after passing through an… … to every 3,000. Austro-Hungarian Empire, population 35,- flexible tubes forms a great obstacle to its extended appli- 904,435, and 14,861 doctors, being 1 physician to every 2,500 cation. : In 1875, the apparatus invented by M. Rouquayrol, and regulating valve, which enables the wearer to breathe…
Internet Archive · Public domain (published before 1931). Free to use for anything.
