[ 136 ] 

 XII. Intelligence and Miscellaneous Articles. 



THE MAGNETISM OF NICKEL AND TUNGSTEN ALLOYS . 



BY JOHN TROWBRIDGE AND SAMUEL SHELDON. 



Introductory . 



r PHE fact that different kinds of steel, alloyed in small propor- 

 ""- tions with tungsten or wolfram, and magnetized to saturation, 

 increase in specific magnetism *, has long been known. Whether 

 the same effect would result from the use of nickel alloyed with 

 tungsten has never been investigated. This paper has for its 

 object a partial answer to the query. It was instigated by Mr. 

 Wharton, proprietor of the American Nickel Works, whose 

 chemist, Mr. Riddle, kindly prepared the alloys which have been 

 employed. These alloys were in two groups. The first, received 

 in November 1888, consisted of three bars of the same shape, one 

 being of pure nickel and the other two having respectively 3 and 

 4 per cent, of tungsten in alloy. These bars were rolled from cast 

 ingots, which were toughened by the addition of magnesium after 

 Fleitmanns method, the magnesium being added just before 

 pouring. They were hot when rolled. The one of pure nickel 

 was afterwards planed into regular shape. Those containing 

 tungsten were too brittle to allow of this manipulation. They 

 were, however, of sufficient regularity to permit accurate measure- 

 ments. This group contained also an octagonally shaped bar with 

 8 per cent, of tungsten, which was prepared like the others, and 

 was afterwards ground into shape. 



The second group, received in May 1889, contained bars which 

 were simple castings, made without the addition of magnesium, 

 and consisted of pure nickel and alloys with 1, 2, 3, and 6 per 

 cent, of tungsten. All the bars in this group were extremely hard 

 and brittle. In making them tungsten oxide, of weight calculated 

 to yield the desired percentage of tungsten in the resulting alloy, 

 was placed with adequate carbon in the bottom of a graphite 

 crucible and covered by the proper weight of pure grain nickel. 

 All was then covered with borax, the lid of the crucible was placed 

 on, and the crucible was heated until reduction and fusion were 

 completed. 



Method. 



As the suspected influence of the tungsten would be to affect 

 the magnetic moment of the bars, these were magnetized to 

 saturation and their specific magnetism then determined, i. e., 

 the magnetic moment for each gram of metal. 



The magnetization was effected by placing the bars separately 

 in a hollow coil whose length was 15 centim. and outside and 

 inside diameters respectively 6 and 3 centim. It consisted of 6 

 layers of wire having 63 turns each. A dynamo current of 40 



* Journ. Chem. Soc. 1868, xi. p. 284, says 300 per cent. 



