604 8 
TABLE II. Tungsten. 
d w je 
0,420 Hea ia 
0,458 ~ 1,255.107 266,0. 10-2 
0,730 | 0,755. 108 | 255,0. 10-3 
1,215 | 1,655.104 935,0. 10-8 
1,645 4,500. 103 342,0. 10-5 
1,885  2,705.103 236,0. 10-5 
2,490 1,340.108 154,0. 10--5 
3335 8,45 .102 | 130,5.10-3 
3,870 6,95 .102 124,0. 10-5 
8,30 1,92 .102 73,8. 10-5 
9,75 1,215.10? 55,0. 10-5 
11,15 6,98 .10! 36,0. 10-5 
19,30 1,79 „101 | 15,5. 10-5 
[20 — 0,5. 10-53] 
With tungsten a perceptible conduction begins to appear at a 
thickness of about 0.5 uu; the strong increase of the resistance begins 
at about 2.5 uu. In this case two further measurements were made 
with wires which glowed at a different temperature; the results 
found were in good agreement with Table II. 
In the measurements with the silver films a more sensitive gal- 
vanometer was used than in those with the platinum and tungsten 
films; had the same sensitiveness been used as with platinum, the 
conduction would have first appeared at a thickness of about 6.5 uu. 
At this thickness of 6.5 uu the platinum film has a resistance of 
about 150 Ohm, that of tungsten one of about 300 Ohm and the 
silver film of 2 x 10° Ohm. The films formed by evaporation thus 
display the same deviation in the case of silver as was found by 
previous observers (comp. page 597). The strong increase of the 
specifie resistance here occurs at a thickness of about 25 uu. 
A few series of measurements with other silver wires undertaken 
with a view to checking the results gave results agreeing in general 
features with those given in Table Il], but there was no approach 
to the constancy of the results obtained with platinum and tungsten. 
We do not consider it altogether impossible, that the behaviour of 
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