While it would be interesting to follow the details of some of the special features of the great producers, it is not practicable in the limited time to do more than call attention to some typical illustrations of mines of different character, or the means employed for their exploitation, and the instances have been selected more with the object of exhibiting prominent features, than as an attempt to cover various details of aperation. They are offered to illustrate the peculiarities of mining

more »

... he different characters of iro~ ore in various sections of the country.* During the present year considerable interest has been attracted to the apparently large deposits of iron ore of a satisfactory character, which can be easily mined from what is known as the Mesabi Range, in Minnesota, and this local-. ity is now passing through the developing stages, which have characterized the earlier history of other sections in the Lake Superior regions which have become producers of iron ore. The pioneers penetrate the forest, generally "packing" their provisions and tools with them, erect a log cabin, and start the preliminary operations with pick, shovel and hand drill, supplemented by hand winch, bucket and pump. If an apparently satisfactory deposit is found, machinery soon takes the place of manual labor, and compressed air is early applied to these enterprises. The necessity of labor saving appliances demands the prompt application of such economies, and not only are power drills introduced in the * The lecture was illustrated by numerous lantern slides. VOL. CXXXV. 2 5 Birktnbine :