138 Intelligence and Miscellaneous Articles. 



in this manner, they showed no appreciable deflexion when placed 

 in position relative to the magnetometer. 



The results tabulated indicate that tungsten greatly increases 

 the magnetic moment of nickel, if the alloy be forged and rolled, 

 but, on the other hand, has but small influence if it be simply 

 cast. Furthermore, changes in the amount of tungsten do not 

 appear to cause corresponding changes in the magnetic properties. 



To see whether the remarkable effect in bars 2 and 3, as com- 

 pared with bar 1, of Group I., was owing to some molecular 

 condition of their surfaces induced by rolling, two bars from the 

 sane steel, one rolled and the other pressed, were magnetized and 

 then measured. The ratio of the specific magnetism of pressed to 

 rolled was as 9 to 5, the rolled haying the smaller amount. The 

 existing difference, in this case, is probably owing to a differe ice 

 in hardness rather than to any molecular condition of the surfaces, 



The specific magnetisms of all the bars are small when compared 

 with good steel magnets. Kohlrausch says that good magnets of 

 common form should have S=40. The bar of ordinary tool steel, 

 however, retained but 7*46. Still it was soft, and by tempering 

 would doubtless have doubled this value. 



If forged nickel and tungsten can be made to maintain a specific 

 magnetism of 10, it will form a useful addition to the resources of 

 physical laboratories. From the high polish of which it is suscep- 

 tible and its freedom from damaging atmospheric influences, it will 

 be most hapily suited for the manufacture of mirror magnets where 

 magnetic damping is to be employed. — Silliman's American Journal 

 of Science, December 1889. 



NOTE ON THE APPLICATION OF HYDEAULIC POWER TO MER- 

 CURIAL PUMPS. BY FREDERICK J. SMITH, M.A., MILLARD 

 LECTURER, TRINITY COLLEGE, OXFORD. 



In vol. xxv. p. 313, 5th series, Phil. Mag., a description is given 

 of the application of hydraulic power to the working of mercurial 

 pumps. 



Since the paper was written the author has ceased to use rubber 

 tubes, and has, in their place, introduced flexible tubes made of 

 steel. As the alteration has proved itself to be satisfactory, and 

 may be of use to those who work with mercurial pumps, or similar 

 apparatus, he ventures to add this note. 



The steel tube is made by the Flexible Metallic Tube Co. in 

 the form of a hollow screw, or tube on which a screw-shaped 

 indentation has been impressed. The outcome of the construction is 

 that while the tube is under a great pressure it is quite flexible, 

 behaving itself in much the same way as a strong rubber tube, with 

 the advantage over the latter of being durable when subject to, 

 constant motion. Several pieces of tube, made of steel and bronze, 

 have been tested up to 200 lb. per square inch, without showing 

 any signs of being injured. These have been used in the labora- 

 tory for connecting together vessels which are subject either to a 



