SPEED ONLY 100 TO ??0 REV. PER M. SAVES HALF THE POWER REQUIRED FOR FAN.
P. H. & F. M. ROOTS, Manuf'rs, CONNERSVILLE, IND.
S. S. TOWNSEND, Gen'l' Ag't, 6 Cortlandt St., NEW YORK.
Scientific American, Vol. XXXVII.—No. 2. [New Series.], July 14, 1877 A Weekly Journal of Practical Information, Art, Science, Mechanics, Chemistry, and Manufactures · 第 182 / 213 题