Page:Popular Science Monthly Volume 38.djvu/178

166 the "blomary fires" could be easily and cheaply smelted, and at the same time furnish larger masses of forgeable metal than the process in common use could supply.

This demand led to the invention of the "Osmund furnace" and the "Stücköfen." Both of these furnaces are of German origin, but it is not absolutely certain which is the older; for, although we hear of the "Stücköfen" as early as the year 1000, we find no mention of the "Osmund furnace" (by that name) until early in the eighteenth century, though furnaces of similar size and construction (called "Blaseofen" and Bauernofen) had been in use in Germany for several hundred years; and as the natural course of development of all mechanisms and apparatus is from the smaller to the larger, or from the less to the more efficient, it is extremely probable that the "Osmund furnace" was the immediate successor of the "blomary" and that the "Stücköfen" (a much larger and loftier construction) followed pretty closely in point of time after it.



The general construction and equipment of an "Osmund furnace" are represented in Fig. 13. This engraving is a copy of one given by Percy as a reproduction of a drawing accompanying a report of a Swedish mining surveyor to the Royal Board of Iron Trade in 1732. A similar engraving (but three times the size) is contained in the work of Swedenborg, who gives in addition a