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Tellurides Process Method

The occurrence of the tellurides of gold and silver, even in small quantities, is so rare that their metallurgical treatment has engaged little attention. A residence of several months at one of the few mines in North America the product of which consists entirely of such ore, has led me to arrange a method for … Read more

French Pocket Compass

The Transactions of the Institute contain nothing, as yet, on the subject of pocket-compasses; and in the belief that American miners, explorers, geologists, and engineers will gladly welcome any information about new forms of apparatus, simple in construction and adapted to rapid use, I offer a short description of an improved French combination pocket-compass, which, … Read more

Electrical Accumulators or Storage Batteries

The broad general distinction between primary and secondary batteries lies in the fact that in the former the current is produced by the consumption of one or both of the elements composing the cell, while in the latter the elements retain their form as such, and merely pass from one state of chemical combination to … Read more

Roasting Furnace

Invented and first put into use, a “new and useful improvement in rotary ore roasting furnaces,” which was intended “to increase the capacity, effectiveness and working economies of such furnaces.” The following description and accompanying figures are taken from the patent papers: Fig. 1 is a side elevation of the feed-end of the Howell rotary … Read more

Testing Aluminum & Metal Alloys

Some explanation of methods of testing will be given before presenting the record of a series of physical tests of aluminum, other metals and alloys. The test-bars used, 12 inches long and ½ inch square, are cast in green sand, with chills bedded in such a way that the ends of the bar run against them. … Read more