MASSACHUSETTS INSTITUTE OF TECHNOLOGY. 271 



great deal less than previous tests on small beams had indicated, and 

 the practice of engineers and architects has since that time been com- 

 pletely modified through the results obtained in this and similar labora- 

 tories. In this way does the work of such a laboratory become of direct 

 and lasting value to the arts. The central piece of apparatus of the 

 Institute laboratory is the Emery machine, similar to the great machine 

 at the Watertown arsenal, with a capacity of three hundred thousand 

 pounds. But in addition to this machine there are a dozen or more 

 other machines designed to test beams, columns, rope, wire and, in fact, 

 materials of every kind and in every form. An interesting machine 

 is that for testing shafts in torsion, and it is instructive to see it twist 



The 100,000 Pound Beam Machine in the Applied Mechanics Laboratory. 



off with apparent ease a steel shaft three inches in diameter, twisting 

 the fibers before they break till the rod resembles a barber's pole. There 

 are also beam-testing machines with capacities up to one hundred thou- 

 sand pounds, in which not only beams but wooden trusses may be tested 

 to the breaking point. Some of the apparatus is of great delicacy; 

 for instance, one instrument will measure the twist of a steel shaft two 

 and a half inches in diameter and six feet long so delicately that the 

 effect of a twist given by one's hand is distinctly visible; scientifically 

 speaking, it will measure an angle of twist of two seconds. There is 

 also a machine designed for testing stone arches, having a capacity of 

 four hundred thousand pounds and suitable for an investigation of 



