198 FIELDS, FACTORIES AND WORKSHOPS. 



from the beginning to the end, with but a few honour- 

 able exceptions.* 



If waste of time is characteristic of our methods of 

 teaching science, it is characteristic as well of the methods 

 used for teaching handicraft We know how years are 

 wasted when a boy serves his apprenticeship in a work- 

 shop ; but the same reproach can be addressed, to a 

 great extent, to those technical schools which endeavour 

 at once to teach some special handicraft, instead of 

 resorting to the broader and surer methods of syste- 

 matical teaching. Just as there are in science some 

 notions and methods which are preparatory to the study 

 of all sciences, so there are also some fundamental 

 notions and methods preparatory to the special study 

 of any handicraft Reuleaux has shown in that delight- 

 ful book, the Theoretische Kinematik, that there is, so 

 to say, a philosophy of all possible machinery. Each 

 machine, however complicated, can be reduced to a few 

 elements plates, cylinders, discs, cones, and so on as 

 well as to a few tools chisels, saws, rollers, hammers, 



* Take, for instance, the description of Atwood's machine in any 

 course of elementary physics. You will find very great attention paid to 

 the wheels on which the axle of the pulley is made to lie ; hollow boxes, 

 plates and rings, the clock, and other accessories will be mentioned before 

 one word is said upon the leading idea of the machine, which is to slacken 

 the motion of a falling body by making a falling body of small weight 

 move a heavier body which is in the state of inertia, gravity acting on it 

 in two opposite directions. That was the inventor's idea ; and if it is 

 made clear the pupils see at once that to suspend two bodies of equal 

 weight over a pulley, and to make them move by adding a small weight 

 to one of them, is one of the means (and a good one) for slackening the 

 motion during the falling ; they see that the friction of the pulley must be 

 reduced to a minimum, either by using the two pairs of wheels, which so 

 much puzzle the text-book makers, or by any other means ; that the clock 

 is a luxury, and the " plates and rings " are mere accessories : in short, 

 that Atwood's idea can be realised with the wheel of a clock fastened, as 

 a pulley, to a wall, or on the top of a broomstick secured in a vertical 

 position. In this case the pupils will understand the idea of the machine 

 and of its inventor, and they will accustom themselves to separate the 

 leading idea from the accessories ; while in the other case they merely 

 look with curiosity at the tricks performed by the teacher with a compli- 

 cated machine, and the few who finally understand it spend a quantity of 

 time in the effort. In reality, all apparatus used to illustrate the funda- 

 mental laws of physics ought to be made by the children themselves. 



