Practical lessons on the lever escapement, its tests, errors, their detection and correction (1916)
Wilkinson, T. J. (Thomas Jessop), b. 1864 · Philadelphia, Penna., Technical publishing company · leaf 19
pallet staff to lowest lock-ing corner of each pallet jewel as directed in item No. 180. PROTRACTORS OR ANGLE MEASURES 105. Students can quickly advance their practical knowledgeof angles and degrees by becoming acquainted with an instrumentfor the measurement of angles called a protractor, as… … Fig. 5 it is an easy matter to count off the degrees enclosed by A B C asan angle of 30 degrees. It is not a difficult matter to becomefamiliar with the various methods of using the protractor. Cheapprotractors are usually unreliable, and the student who intendsto pursue a thorough course in…
Clocks and watches
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