276 Mr. W. Brown on Steel Magnets. 



These curves, when examined along with Table I., are very 

 interesting. 



Fiff. 2. 



Dimension ratio l/d . 



From a magnetic point of view, specimen II. seems to be 

 the best of the three; since with a magnet, whose dimension 

 ratio is 19, we get a magnetic moment as great as one with 

 dimension ratio of 23"5 of either specimens I. or III. Spe- 

 cimens II. and III. are about equal with magnets 10 centim. 

 long, or a dimension ratio of 35. We see also that there 

 would be very little gain by making a magnet from speci- 

 men I. longer than 8 centim., and 10 centim. appears to be 

 the length for No. III., whilst No. II. rises abruptly up to 

 even 20 centim. 



This behaviour of No. II. is somewhat curious ; it contains 

 the least silicon and the most phosphorus of the three, and an 

 intermediate quantity of manganese, and in the condition in 

 which it came from the manufacturer it is the hardest and the 

 most elastic of the three specimens ; it is also very fibrous, 

 tough, and difficult to straighten. 



No. III. is something like II. in its physical qualities, only 

 not so pronounced in the qualities mentioned ; whereas No. I. 

 is milder, softer, and more easily worked than the other two. 

 It ought to be mentioned that II. and III. are by one maker, 

 and I. by another. 



