ACKNOWLEDGMENTS xvii 



163, a, 6; North Public Health Bureau, Figs. 146, 147; Rensselaer 

 Valve Co., Fig. 167; Thompson Meter Co., Fig. 170; National 

 Meter Co., Figs. 171, 172, 173; Haines, Jones & Cadbury Co., 

 Figs. 174, 175, 176, 177, 178, 179, 182, 183, 184, 185, 186, 187, 188; 

 A. W. Wheaton Brass Works, Fig. 180; Ladies' Home Journal, 

 Figs. 192a, 1926; H. K. Mulford Co., Figs, on pages 309, 311, 315, 

 316, 317, 319; Warner-Lenz, Figs. 202, 212, 213; Bausch & Lomb, 

 Figs. 203, 204, 205, 216, 221, 231, 229; American Medical Associa- 

 tion, 206, 207, 208, 209, 210, 211, 222, 229; Chas. Besseler, Fig. 217; 

 Nicholas Power Co., Figs. 218, 220; Pennsylvania Rubber Co., 

 Figs. 37, 219; De Le Vergne Machine Co., Fig. 5; Hotpoint Co. 

 for numerous illustrations; Illuminating Engineering Society, Fig. 

 252; Mr. H. L. Hunt of C. H. Ditson Co., for Figs. 217, 338, 339, 

 340, 341, 342, 379; Thomas Edison, Figs. 327, 327a, 328; New York 

 Telephone Co., Figs. 335, 336, 337; Westinghouse Electric & Man- 

 ufacturing Co., X-Ray picture of watt meter; De Laval Separator 

 Co., Fig. 377; Thor Washing Machine Co., Fig. 38; Underwood 

 Typewriter Co., Fig. 381; Walker Brothers Co., Fig. 382; Singer 

 Sewing Machine Co., Figs. 383, 384, a, 6, c, d; Scientific American, 

 Fig. 373; Weston Instrument Co., Figs. 265, 266, 274, 275, 279; 

 Landers, Ferris & Clark, X-Ray of coffee percolator; Aeolian Co., 

 Figs. 310, 311, 312, 313, 314; Illustrated World, Figs. 387, 388; 

 General Fire Extinguisher Company, Figs. 100, 102, 103. 



