458 



Prof. Beetz on the Influence of Magnetization 



could have caused an error with respect to the origin of these de- 

 flections : the magnetizing spirals were at a distance of 12 metres 

 from the galvanometer; and, to ensure greater certainty, the 

 measuring current in the bridge was first sent in one direction 

 and then in the other, by which the deflections were made op- 

 posite in direction, but they continued equal in amount. An 

 inversion of the magnetizing current, on the contrary, produced 

 no effect. The resistances measured were as follows : — ■ 









Resistance. 



No. 



Wire. 



Tension. 















Unmagnetized 



Magnetized. 



10 



Annealed ... 



grms. 

 400 



7-2960 



7-2985 







600 



2970 



2995 







1000 



2990* 



3015 



11 



Covered 



100 



4-2795 



4-2820 







200 



2800 



2825 







400 



2820 



2845 







600 



2828 



2855 







1000 



2805 



2830 





Annealed ... 







4-4025 



4-4050 







100 



3830 



3855 







600 



3840 



3865 







1000 



4870 



4895 







2000 



4105 



4130 



The following experiments were made with greater lengths 

 than the apparatus previously used permitted. 



No. 12. An iron wire of 1*3 millim. diameter was bent back- 

 wards and forwards ten times, so as to form a bundle 270 mil- 

 lims. in length ; the individual layers were carefully insulated by 

 means of sheet gutta percha, and the bundle, surrounded by the 

 cooling- tube, was placed in a magnetizing spiral 230 millim s. 

 in length. 



No. 13. A bundle of covered wire 036 millim. thick was 

 made, 270 millims. in length and in 100 layers. 



No. 14. A bundle, 190 millims. in length and in 142 layers 

 was made of the same kind of wire. 



No. 15 . A wire 0*24 millim. thick was stretched backwards and 

 forwards between two wooden disks, so that it formed 32 layers 

 each 1390 millims in length. One disk was suspended at its 

 centre, and on the other a weight of 1 kilogrammes hung; so that 



* These three experiments were made in rapid succession. The increase 

 in resistance with the tension quite corresponds to the statement which 

 Mousson has made. The following series was made on different days, so 

 that individual experiments are not always comparable, owing to small dif- 

 ferences in temperature. 



