The author is particularly indebted in the preparation of this book to John G. Thompson, professor of economics, University of Illinois; J. K. T. Ekblaw, instructor of farm mechanics, University of Illinois, and editor of Farm Power; Andrey A. Potter, professor of steam and gas engineering, Kansas State Agricultural College; J. M. Bryant, professor of electrical engineering, University of Texas; Harrison E. Howe, National Council of Research; Miss Minna C. Denton, home economics specialist, United States Department of Agriculture; Miss Marie Dallas, Washington, D. C.; F. F. Good, instructor in applied physics, Teachers' College, Columbia University, New York.

The following is a list of companies furnishing illustrations, data and other information:

American Blower Company.
American Ironing Machine Co.
American Lava Co.
American Radiator Co.
American Stove Co.
Automatic Electric Washer Co.
Baltimore Gas Appliance Co.
Bates & Edmonds Motor Co.
Bissel's Carpet Sweeper Co.
Blake Mfg. Co.
C. Brown Mfg. Co.
B. Bryan Co.
Central Construction & Supply Co.
Central Oil & Gas Stove Co.
Chambers Fireless Cooker Stove Co.
Geo. M. Clark & Co.
Cleveland Metal Products Co.
Coleman Lamp Co.
Consolidated Gas, Electric Light
and Power Co.
Cyphers Incubator Co.
Dangler Stove Co.
Davis Acetylene Co.
The DeLaval Separator Co.
Delco Motor Co.
The Deming Co.
Detroit Heating & Lighting Co.
Detroit Stove Works.
Detroit Vapor Stove Co.
A. B. Dick Co.
W. S. Dickey Clay Mfg. Co.
The Durham Mfg. Co.
Eagle Generator Co.
Fuller, Warren & Co.
General Electric Co.
Hammond Typewriter Co.
Hart & Crouse Co.
Herrick Refrigerator Co.
Huenfield Co.
Humphrey Co.
Hurley Machine Co.
Kalamazoo Stove Co.
Kewanee Water Supply Co.
Klau-Van Pietersom-Dunlap.
Landers, Frary, Clark & Co.
Laundryette Mfg. Co.
Manning, Bowman & Co.
Mantle Lamp Co. of America.
H. G. McFadden & Co.
The Monitor Stove Co.
National Electric Supply Co.
Northwestern Steel & Iron Works.
Pacific Flush Tank Co.
Potomac Power & Lighting Co.
Rathbone, Sard & Co.
Reliable Stove Co.
Remnert Mfg. Co.
Rhinelander Refrigerator Co.
Ringen Stove Co.
Rochester Rotary Washer Co.
Rochester Stamping Co.
Sears, Roebuck & Co.
Sharples Separator Co.
Singer Sewing Machine Co.
L. C. Smith & Bros. Typewriting Company.
Standard Oil Co.
Edward L. Stock.
Thatcher Furnace Co.
The Torrington Co.
Toledo Cooker Co.
Trenton Potteries Co.
United Electric Co.
United Pump & Power Co.
United States Dept. of Agriculture.
United States Radiator Co.
Voss Bros. Mfg. Co.
Walker Bros. Co.
Welsbach Co.
Western Electric Co.
White Frost Refrigerator Co.
White Mop and Wringer Co.
Wilcox & Gibbs Sewing Machine Co.
The Yale & Towne Mfg. Co.