1 78 SCIENTIFIC AND TECHNICAL EDUCATION 



the pupil entering on practical work should know. But the 

 examiner of the Science and Art Department has understood 

 Applied Mechanics to mean a knowledge of machinery a know- 

 ledge which no man can acquire except by long practice, and 

 which a pupil entering a workshop can by no means have 

 acquired ; indeed, no man in his whole lifetime ever acquires it 

 thoroughly except in certain branches of machinery. 

 One question asked is 



15. In the older vertical saw frames a ratchet wheel was em- 

 ployed to urge the timber forward for the cut ; in modern frames a 

 similar arrangement is employed, but with this difference, that the 

 teeth of the ratchet wheel are dispensed with, and a frictional grip, 

 adjustable to any rate of feed motion, is substituted. Make a pen- 

 and-ink sketch of any such contrivance by which the object can be 

 effected. 



Another is as follows : 



16. Lathes for boring guns are now being constructed, in which 

 the power is to be accumulated by worm gear instead of spur or 

 bevel gear. The accumulation of power is 1 50 to 1 ; a worm wheel 

 is fixed on the main spindle, and the worm works in oil. Make a 

 sketch of the head stock only, showing the driving pulleys and the 

 gear. 



Now, unless a man be told beforehand, ' You will be examined 

 in sawing machinery, and in machinery for the manufacture of 

 ordnance,' I hold that his knowledge or state of preparation 

 cannot be tested by questions like these. If I am to be at 

 liberty to pick any details from any class of machinery, and ask 

 men to make a sketch of it, the merest accident will determine 

 who would give me the best answer. Probably, if I were to ask 

 the examiner to sketch the form of break employed in retarding 

 submarine cables during submersion, and describe its principles, 

 he would be as much puzzled as I should be to sketch a detail 

 in gun-boring machinery. The questions require no particular 

 knowledge of the principles of mechanics, but an absolutely 

 unlimited knowledge of the details of machinery ; and to my 

 mind it is absurd to ask from pupils about to enter on a course 

 of practical study any but the most elementary knowledge of 

 the elementary parts of machines. 



