446 SEC. 12. APPLIED MECHANICS. 



424. Apparatus for determining the relative Resistance to 

 flexure, and the elasticity of woods and timber. 



Prof. Dr. Nordlinger, Holienheim, Wurtemburg. 



427. Phroso-dynamic Apparatus for testing wires, by 

 M. Alcun. M. Dig eon, Paris. 



1927. Cast-iron Test Bars. Specimens to illustrate the 

 form and position of fractures when exposed to a breaking load. 



W. J. Millar, C.E. 



The bars were of 36" span, 2" deep, and 1" broad. 



The load was applied at centre of bars. Straight fractures occurred when 

 bars broke at, or close to, centre of span ; but curved fractures when bars 

 broke at points more or less removed from centre. 



1927a. Metallometer for Testing Metals and Alloys 



by bending backwards and forwards a number of times through 

 a certain angle. Lewis Olrick. 



1957b. Drawings of Hydraulic Apparatus for the study 

 of the extension, compression, and flexion of prismatic bars. 

 Constructed by Professor Wischnegradski. 



Mechanical Laboratory, Technological Institute, St. 

 Petersburg. 



This apparatus consists of a hydraulic cylinder, the piston of which bears 

 a table supporting four iron columns, connected at the top by a strong 

 cast-iron cross-head, that has at the centre a conical opening, and below 

 a spherical recess within which pivots a hemispherical cast-iron piece, 

 traversed by a powerful iron screw fixed by two nuts ; to this screw is 

 attached the upper end of the bar subjected to the experiment of extension ; 

 the lower end of the bar is fastened to the large lever placed at the base of 

 the apparatus and which pivots round an axle fixed in an immovable bearing. 

 This lever is connected with the upper lever, by means of two iron braces 

 suspended to one end of this lever ; at the other end is hung a scale >pan 

 for the weights used in calculating the tension effected. The ratio of the two 

 arms of the lower lever is 5, and that of the two arms of the upper lever is 

 20. So that each lever being perfectly balanced the tension of the bar is 

 exactly 100 times that of the weight on the scale board. By means of the 

 screw described above, and by inverting the intermediate iron pieces, it is 

 possible, with this apparatus, to experimentalise upon bars of any length 

 up to 10 feet English. 



No. 1 represents the apparatus arranged for experiments of extension. 



No. 2 represents the apparatus arranged for experiments of flexion. 



No. 3 represents the apparatus arranged for experiments of the com- 

 pression of long bars. 



The deformations in the bars are measured with a cathetometer constructed 

 by Mr. Brauer, and the original section of the bar with an apparatus by 

 the same engineer. The readings are given to the ^ of a millimeter. 



