Text-books, such as relate to construction, consist generally of examples, drawings, and explanations of machines, gearing, tools, and so on; such examples are of use to a learner, no doubt, but in most cases he can examine the machines themselves, and on entering a shop is brought at once in contact not only with the machines but also with their operation. Examples and drawings relate to how machines are constructed, but when a learner comes to the actual operation of machines, a new and more interesting problem is reached in the reasons why they are so constructed.
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38During the last days hundreds of lads had left Louvain for The Netherlands, and the migration went on throughout the whole occupied part of Belgium. It was the exodus of the levies of 1914 and 1915, who had been called up, and many of whom had been sent to Germany as prisoners. The Germans themselves had not a little furthered the flight of these crowds; by proclamations they had warned the lads not to try to escape, for otherwise all of the levies of '14 and '15 would be taken prisoners, and the parents of the fugitives would be punished. At Heverlee and Louvain the lads of both levies had to present themselves every Friday at this station. The consequence was that the following Friday not one single boy of those levies was to be found in either place.Only the raucous cry of a seagull cut into that chill silence!A proof of this last proposition is found in the fact that a thorough latheman will perform nearly as much work and do it as well on an old English lathe with plain screw feed, as can be performed on the more complicated lathes of modern construction; but as economy of skill is sometimes an equal or greater object than a saving of manual labour, estimates of tool capacity should be made accordingly. The main points of a lathe, such as may most readily affect its performance, are firsttruth in the bearings of the running spindle which communicates a duplicate of its shape to pieces that are turned,second, coincidence between the line of the spindle and the movement of the carriage,third, a cross feed of the tool at a true right angle to the spindle and carriage movement,fourth, durability of wearing surfaces, especially the spindle bearings and sliding ways. To these may be added many other points, such as the truth of feeding screws, rigidity of frames, and so on, but such requirements are obvious."I suppose, madame, that you have an old 'bike' to sell?"
