1C 
DE. A. MATTHIESSEN AND M. VON BOSE ON THE INELTJENCE OF 
The formulee deduced from the observations, from which the conducting powers were 
calculated, were — 
For fii-st wire . X=8-3882-0-032346#+0-00007540?5^ 
For second wire X = 8-3147— 0’032055^+0'00007307^^ 
For third wu’e . X=8'2925 — 0'032468if+0‘00008011^^ 
The value found for the conducting power of lead was 
o Eeduced to 0'’. 
7-77 at 17*3 8-304. 
Treating the mean of the values as above, the formula is 
X=8-318-0-032237^+0-00007608f. 
Arsenic. 
Purified by sublimation. Small bars were cut from a comparatively solid piece and 
soldered to two copper mres ; on account of the extreme brittleness of arsenic, the 
bars were placed in glass tubes closed at the ends with gypsum, through which the 
copper tvires passed. As these were dried in a water-bath for several days, no permanent 
alteration of the conducting power of the bars was found after being heated in the 
oil-bath for two days. The values found for the conducting power of arsenic agree as 
well as could be expected, considering the bars were made by hand, and the metal 
somewhat porous. The difiiculty of obtaining bars of metal of sufficient length is so 
great that we have been contented with two series. These are given in Table JX. 
Table IX. 
First bar. 
Second bar. 
Length 
Diameter 
5J0'4 millims. 
0*93 millim. 
55-5 millims. 
1*01 millim. 
The means of the conducting powers found for each of the following temperatures 
were — 
T. 
Conducting power. 
Difference. 
T. 
Conducting power. 
Difference. 
Observed. 
Calculated. 
Observed. 
Calculated. 
14*20 
5 0203 
5*0180 
+ 0*0023 
13*50 
4*0051 
4*0037 
+ 0*0014 
25*30 
4*8007 
4*8008 
— 0*0001 
24*50 
3*8371 
3*8450 
-0*0079 
37*80 
4*5710 
4*5736 
—0*0026 
40*15 
3*6367 
3*6311 
+ 0*0056 
55*00 
4*2854 
4*2906 
— 0*0052 
55*55 
3*4447 
3*4341 
+ 0*0106 
70*00 
4*0767 
4*0722 
+ 0*0045 
69*90 
3-2559 
3*2628 
-0*0069 
85*30 
3*8810 
3*8764 
+ 0*0046 
82*50 
3*1144 
3*1221 
— 0*0077 
101*00 
3*7005 
3*7041 
—0*0036 
99-80 
2*9485 
2*9435 
+ 0*0050 
The formulee deduced from the observations, and from which the conducting powers 
were calculated, were — 
For first bar X=5-3168— 0-0218742^+0-00005848^. 
For second bar X=4•2078-0•015506^+0■00002843^!^ 
