Mr. W. Brown on Steel Magnets. 



271 



numbers of this Journal for 1887. The experiments now to 

 be described were carried out in the Physical Laboratory 

 of Glasgow University. The magnets were cylindrical bar- 

 magnets, 10 centim. in length, made from Ithree different 

 specimens of steel of very approximately known composition, 

 and the principal object of this communication is to show the 

 effective lengths of magnets made from the same specimens of 

 steel. 



For convenience of reference I here reproduce, in a 

 modified and curtailed form, Tables I., II., III., giving the 

 main results of the papers above mentioned. Table I. gives 

 the relative percentage proportions of all the substances found in 

 the steel, the quantities in specimen I. being taken as unity. 

 Table II. gives the dimensions of the magnets, and Table III. 

 the main features of the collected results. 



Table I. — Comparative Composition of the Specimens. 



Substance. 



Number of specimen. 



I. 



II. 



III. 



Silicon 



100 

 1-00 

 1-00 

 1-00 

 1-00 

 1-00 



0-08 

 1-23 

 1-71 

 000 

 0-25 

 0-994 



017 

 3-25 

 1-55 

 0-00 

 0-25 

 0-987 



Manganese 



Phosphorus 



Sulphur 



Carbon 



Iron 





Table II. — Dimensions of Magnets. 



Number of 

 specimen. 



Length of 



magnet, in 



centimetres, 



l. 



Diameter of 



magnet, in 



centimetres, 



d. 



Dimension, 

 ratio Ijd. 



Weight of 

 magnet, 

 in grms. 



I 



11 



Ill 



10 

 10 

 10 



0-300 

 0-265 

 0-270 



33 



38 

 37 



5-5 

 4-3 

 4-5 



