90 BAILEY TESTING MACHINE. 



a short shackle which is attached to a continuation of the 

 piston rod of the straining cylinder. The left-hand end is 

 similarly held in a shackle, which is linked to the short arm 

 of the hanging lever shown below the bed of the machine. 

 The load on the specimen is applied by pumping water 

 from the small hand pump shown, into the straining 

 cylinder. This puts a pull on the specimen, which pull, 

 when it is applied to the lever, tilts it upwards, the amount 

 of load being proportional to the sine of the angle through 

 which it is deflected from the vertical. This load is directly 

 indicated by a pointer moving over a graduated dial, a 

 second loose pointer bein<* carried round by the first, and 

 left at the maximum loaa. The graduations on the dial 

 are determined by applying known loads to the lever. 

 The only thing necessary, therefore, in making a test is to 

 gradually apply the hydraulic pressure until fracture takes 

 place. A small oil cataract cylinder is provided to prevent 

 the lever from falling too suddenly when the specimen 

 breaks. Additional parts ar/s supplied for compression and 

 cross-breaking tests 



The machine illustrated has, in addition to these ordi- 

 nary appliances for the testing of materials, some 

 apparatus, shown at the right-hand end of the machine, for 

 testing pressure and vacuum gauges. In some of these 

 machines, instead of an hydraulic straining cylinder, a 

 screw, worm-wheel, and worm are used for taking up the 

 stretch. 



These machines are made in two sizes, having maximum 

 capacities of 1,000 Ib. and 5,000 Ib. respectively, and taking 

 in tension specimens up to 18 in. in length. 



45. Ster- Hydraulic Testers. Sir W. H. Bailey and 

 Co. also make a number of small testing machines for 

 transverse, torsional, and tensile tests, in which the load 

 on the specimen is measured and indicated by the pressure 

 of mercury on a flexible diaphragm, which supports the 

 load in a similar way to that adopted in the Emery machine, 

 already briefly described. The pressure of the mercury is 

 indicated by its height in a vertical tube, as well as in an 

 ordinary pressure gauge. These machines, b esides being 

 convenient to use, give very accurate readings. 



46. Testing Machines of other Countries. In testing 

 machines, as in most other things, fashions prevail. 

 Certain machines and certain types of machines are 

 generally popular in one country. In Britain, perhaps, 



