Mechanical Vibrations upon Magnetization. 469 



mechanical vibrations upon magnetization would be more 

 complete. 



It became immediately apparent, as soon as this inves- 

 tigation was commenced, that, had the experimental methods 

 of earlier investigations dealing with the magnetic effects of 

 vibrations been such as to elucidate the various phenomena 

 involved, the results of later investigators (Ascoli, Arno, 

 Walter and Ewing, Garibaldi, Marconi, Maurain, Piola, 

 Rutherford, Wilson, and others) relative to the effects of 

 electric oscillations upon magnetism would have fallen more 

 readily into line with each other * and with the effects of 

 purely mechanical vibrations. 



Apparatus. — To obtain satisfactory quantitative measure- 

 ments the vibrations must be produced in such a way that 

 they can readily be put " on " and " off," and that when on 

 they remain constant in character and intensity. Such a 

 result was very approximately attained by experimenting 

 with wires attached to the gong of an ordinary electric bell. 

 The wires were hooked at their ends, and one extremity of a 

 wire could be linked to the gong, the other to the vertical 

 arm of an L- shaped lever, preferably by means of a short 

 length of thread. A weight of 11 ozs. suspended from the 

 horizontal arm of the lever subjected each wire under test to 

 a pulling stress not greater than 05 kilo, per sq. mm. of 

 sectional area. The effect of this load and the possibility of 

 torsion are discussed in the paper. Iron (not soft), steel 

 (mild), and nickel wires, 100 cms. in length and approximately 

 0"092 cm. diameter, were used in an annealed and also in a 

 quenched condition. Each wire under test was in a hori- 

 zontal position, at right angles to the earth's field, and 

 coincided with the axis of a maorietizino; solenoid 4:1 cms. 

 long. An exploring coil and ballistic galvanometer measured 

 the magnetic intensity at approximately the central position 

 of the wire. 



Superposition of Vibrations and Field. — The effects of 

 vibrations have in general been investigated by tapping — 

 that is to say, vibrations have been superposed upon field. 

 But the effects of vibrations cannot be limited to one method 

 of relative superposition of vibrations and field. Change of 

 field may be superposed upon the magnetic metals kept in a 

 state of continuous vibration. These methods are entirely 

 dissimilar, and the recognition of this fact is of primary 



* ''Notes on the Effect of Electric Oscillations on Magnetism,'' 

 L. H. Walter, 'The Electrician,' May 5, 1905; also 'Science Abstracts,' 

 vol. viii. Section A, Abst. 1290. 



