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Show TH PRINCIPLE O SCIENTIFI MANAGEMEN 5 required a period of 26 years to investigate the effect of these twelv variables upon the cutting speed of metals To those, however who have had personal experience as experimenters, it will be appreciated that the great difficulty of the problem lies in the fact that i And in fact the great lengt contains so many variable elements of time consumed in making each single experiment was caused b the difficulty of holding eleven wvariables constant and unifor throughout the experiment, while the effect of the twelfth variabl was being investigated Holding the eleven variables constant wa far more difficult than the investigation of the twelfth element As, one after another, the effect upon the cutting speed of eac of these variables was investigated, in order that practical use coul be made of this knowledge, it was necessary to find a mathematica formula which expressed in concise form the laws which had bee obtained As examples of the twelve formulse which were developed the three following are given 7 V = P = 45000 D¥F 11. > 0237 4 F0.665 <-3-- After these laws had been investigated and the various formula which mathematically expressed them had been determined, ther still remained the difficult task of how to solve one of these complicated mathematical problems quickly enough to make this knowledg If a good mathematician who had thes available for every-day use various formula before him were to attempt to get the proper answe (1.e., to get the correct cutting speed and feed by working in th ordinary way) it would take him from two to six hours, say, to solv a single problem; far longer to solve the mathematical proble than would be taken in most cases by the workmen in doing th Thus a task of considerable magniwhole job in his machine tude which faced us was that of finding a quick solution of thi problem, and as we made progress in its solution, the whole problem was from time to time presented by the writer to one afte anothe wer o offere th note an reasonabl to be used in its solution it others for th sak i mathematician fe Som of bein fo rapid The country thi practica metho of these men merely glanced a courteous kep it befor the for some two or three weeks. They all gave us practically the sam answer: that in many cases it was possible to solve mathematica problems which contained four variables, and in some cases problem |