Calipers: “Lord Chancellor,” 45, 211; vernier, 203; micrometer, origin of, 211-213. Campbell, A. C.: 237. Camus: 64; “The Teeth of Wheels,” 64-65, 68. Carmichaels, of Dundee: engine makers, 86. Carron Iron Works: 2, 85. Change-gear box: 182. Chase Rolling Mills Co.: 236. “Chordal’s Letters”: 261. Cincinnati, Ohio: tool building in, 266-267. Cincinnati Bickford Tool Co.: 272. Cincinnati Milling Machine Co.: 272. Cincinnati Planer Co.: 271-272. Cincinnati Screw & Tap Co.: 272. Clement, Joseph: 7, 8, 9, 57-58, 59, 99, 107; screw-thread practice, 10, 19, 57, 58-59, 101; gear practice, 68; taps and dies, 10, 19, 58; lathes, 19, 57; planers, 19, 50, 52, 54, 59; relations with Bramah, 19, 58; with Maudslay & Field, 19, 46, 58. Cleveland, Ohio: 183. tool builders in, 261-266; first multi-spindle automatic screw machines, 265. Cleveland Twist Drill Co.: 266. Clock industry in Connecticut: 171-172. Coe, Israel: 236. Coe, Lyman: 234, 236. Coe Brass Co.: 234. Coes Wrench Co.: 226. Colby, Gilbert A.: 254. Collins Co.: axe makers, 169. Colt, Samuel: 166-168; interchangeable system, 137, 168; Colt revolver, 166, 167; erection of Armory, 167, 168. Colt Armory: 165, 166; erection of, 167, 168; a “contract shop,” 178. Conradson, Conrad N.: turret machine, 276. Cook, Asa: 174. Coombs, S. C.: 222. Corliss Machine Works: 126. Cotton crop: growth of, 150-151. Cotton gin: invention of, 131, 148 _et seq._; influence, 114, 131, 145, 149, 150-151, 161; patent rights of, 151-158. Cowie, Pierson: 221-222. Cramp Ship Building Co.: 257. Croft, James: brass worker, 232. Crompton, William: 114. Cup-leather packing: 18. Currier & Snyder: 222. Cushman, A. F.: 173. Darby, Abraham, 3d: first iron bridge, 15. Darling, Samuel: graduating engine, 203, 204. Davenport, James: textile machinery, 246. Davenport, William S.: 214. da Vinci, Leonardo: anticipation of modern tools, 6, 36. Davis, Charles: 269. Davis, Jefferson: on Whitney’s steel-barreled muskets, 160. Davis & Egan: 269. D’Eichthal, Baron: partner of Bodmer, 75. De la Hire: gear teeth, 63, 64, 67. DeLeeuw, A. L.: 273, 277. Dennison, A. L.: American Watch Co., 144. de Vaucanson, Jacques: milling cutter, 206. Diametral pitch: “Manchester pitch,” 70 note 66; Bodmer, 80. Die forging: 137. Dietz, Schumacher & Boye Co.: 268. Dodge, Cyril: 126. Dodge, Nehemiah: goldsmith, 126. Dougherty, James: 254. Draper Machine Tool Co.: 222. Dresses, Henry: 271. Dresses, Mueller & Co.: 271. Drilling machines: in 18th century, 4. Drop hammer: developed in America, 5, 143, 175. Dwight, Dr. Timothy: on Pawtucket, 121.