.1883.] On the Circumpolar Expedition to Fort Rae. 



173 



Table IV gives the complete results of the mechanical, chemical, 

 and physical tests upon a series of wires furnished by Messrs. Fre- 

 derick Smith and Co., of Halifax. 



The tensile strength and electric conductivity are those furnished 

 me by Messrs. Smith and Co. The chemical analyses by Mr. Henry 

 S. Bell, of Sheffield, the magnetic capacity of the bright hard drawn, 

 annealed, and tempered wires, were determined by myself by the aid 

 of the magnetic balance. 



In the above Table IV there is a complete relation between electric 

 conductivity and magnetic capacity, both progressing in a similar 

 ratio and agreeing in a most remarkable manner. 



We see here that the electric conductivity and magnetic capacity 

 have a complete relation to each other, but while in every wire 

 measured I have found this true, it is only so when the wire has been 

 completely annealed and free from mechanical strain, and a feeble 

 magnetic force employed, thus the relation exists only in the limited 

 sphere of elastic rotation already mentioned. 



I believe the relation here shown between electric conductivity and 

 magnetic capacity to be of theoretical importance and of practical 

 utility, as we at once find not only the electric conductivity of iron 

 and steel from a simple reading of their magnetic capacity, but also 

 the iron most suitable for the cores of electro-magnets. 



II. " Report on the Circumpolar Expedition to Fort Rae." By 

 Captain H. P. jJAWSoN, R.A. Communicated by Professor 

 G. (1. Stokes, Sec. R.S. Received December 12, 1883. 



On the 14th April, 1882, I was informed that I was appointed to 

 the command of the Circumpolar Expedition. I at once proceeded to 

 London, and was occupied until the day of sailing in practice with the 

 magnetic instruments at the Kew Observatory, and the purchase of 

 stores, &c, for the expedition. 



On the 1st May, Sergeant F. W. Cooksley, Royal Horse Artillery, 

 and Gunner C. S. Wedenby, Royal Artillery, and on the 6th May 

 Sergeant Instructor of Gunnery J. English, R.H.A., reported them- 

 selves to me, and commenced attendance at Kew for instruction. 



Journey to Fort Rae. 



We sailed from Liverpool on the 11th May, and arrived at Quebec 

 on the 23rd. Here I spent some days finding that the steamer for the 

 north did not leave Winnipeg till the 10th June, and my party was 



