﻿128 Mr. T. Graham on the Relation of 



the degree of tenacity that still remains is reconcilable with any 

 other view than that the second element present possesses of 

 itself a degree of tenacity such as is only found in metals. 



3. Electrical Conductivity. — Mr. Becker, who is familiar with 

 the practice of testing the capacity of wires for conducting elec- 

 tricity, submitted a palladium wire, before and after charging 

 with hydrogen, to trial, in comparison with a wire of German 

 silver of equal diameter and length, at 10 o, 5. The conducting- 

 power of the several wires was found as follows, being referred to 

 pure copper as 100 : — 



Pure copper ....... 100 



Palladium 8' 10 



Alloy of 80 copper +20 nickel . 6'63 



Palladium + hydrogen . . . 5*99 



A reduced conducting-power is generally observed in alloys ; and 

 the charged palladium wire falls 25 per cent. But the conduct- 

 ing-power remains still considerable, and the result may be 

 construed to favour the metallic character of the second consti- 

 tuent of the wire. Dr. Matthiessen confirms these results. 



4. Magnetism. — It is given by Faraday as the result of all his 

 experiments, that palladium is "feebly but truly magnetic;" 

 and this element he placed at the head of what are now called 

 the paramagnetic metals. But the feeble magnetism of palla- 

 dium did not extend to its salts. In repeating such experiments, 

 a horseshoe electromagnet of soft iron, about 15 centims. (6 inches) 

 in height, was made use of. It was capable of supporting 60 

 kilogs. when excited by four large Bunsen cells. This is an 

 induced magnet of very moderate power. The instrument was 

 placed with its poles directed upwards ; and each of these was 

 provided with a small square block of soft iron terminating la- 

 terally in a point, like a small anvil. The palladium under 

 examination was suspended between these points in a stirrup of 

 paper attached to three fibres of cocoon silk, 3 decimetres in 

 length, and the whole was covered by a bellglass. A filament 

 of glass was attached to the paper, and moved as an index on a 

 circle of paper on the glass shade divided into degrees. The 

 metal, which was an oblong fragment of electro-deposited palla- 

 dium, about 8 millims. in length and 3 millims. in width, being 

 at rest in an equatorial position (that is, with its ends averted 

 from the poles of the electromagnet), the magnet was then charged 

 by connecting it with the electrical battery. The palladium was 

 deflected slightly from the equatorial line by 10° only, the mag- 

 netism acting against the torsion of the silk suspending thread. 

 The same palladium charged with 604*6 volumes of hydrogen 

 was deflected by the electromagnet through 48°, when it set 



