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POPULAR SCIENCE MONTHLY. 



many questions concerning these uncertain structures; also machinery 

 for studying the wear of brake shoes and wheel tires, a subject in regard 

 to which there is room for much investigation. Finally, mention 

 should be made of machinery for investigating the interesting subject 

 of the effect of repetition of stress. 



The tests performed in the engineering laboratory cover almost the 

 entire range of mechanical science. Sometimes investigations are car- 

 ried on through a number of years; for instance, during three successive 

 years experiments were conducted and formed the subject of theses on 

 the proper method of counterbalancing the reciprocating parts of a 



locomotive. Xor are the tests performed by the Institute students as 

 a regular part of their instruction confined to these laboratories, as is 

 made evident by the fifty-hour test of the West End Street Eailway 

 power station and the twenty-four hour test of the pumping engine at 

 Chestnut Hill, both recently carried out. 



In connection with the engineering laboratories, brief mention may 

 be made of the shops, which form an important adjunct of the labora- 

 tories. They consist of a shop for carpentry, wood-turning and pattern- 

 making, equipped with forty carpenters' benches, thirty-six pattern- 

 makers' benches and a full equipment of saws, planers, lathes, etc.; a 

 foundry with a cupola furnace for melting iron, thirty-two moulders' 



