965 
to obtain a similar effect with tungsten. Therefore the difference 
between the temperature of evaporation and the temperature of 
condensation is for silver only 600°, for tungsten nearly 3000°. 
The “refrigeration“ of the tungsten-vapour is thus exceedingly 
strong and therefore we may expect the state of agglutination 
of the tungsten-condensate on the bulb to differ but immaterially 
from that in the state of vapour. From the behaviour of tungsten 
towards nitrogen we deduce that the tungsten-vapour is mono- 
atomic'). From KNUupseN’s *) measurements of the accommodation- 
coefficient I. Lanemurr*) too draws the conclusion that a reflection 
of the tungsten-atoms against a cold surface is highly improbable 
(c. f. besides p. 963). So we may expect that the tungstenatoms are 
immediately fixed by the bulb they collide against and will not find 
any opportunity for the formation of large conglomerations. 
If the mere conglomeration of molecules is difficult, an arrangement 
as required by the crystallised state. will surely not take place. 
Hence the state of the tungsten-deposit will agree with that of 
the rocksalt-deposit, with the amorphous-vitreous. 
The thickness of this layer is extrememely slight. A bulb of 
120 c.m?. covered with 0.12 m.gr. tungsten was already decidedly 
grey-coloured. If we fix the specific weight of tungsten at 20, then 
the thickness of that layer is calculated 0.5 wu. But layers of a 
fourfold thickness were quite insoluble (optically) as well. *) 
N 
Deposits of metal obtained by means of Cathodic Atomizing. 
By cathodic atomizing as well, very thin deposits of metal may 
1) I. Langmuir. Journ. Amer. Chem. Soc. 35, 931 (1913). 
2) Ann. d. Physik, 34, 593 (1911). 
3) Phys. Review 19132, 332. C. f. also, Ibid 1916? 149. 
4) This difference in dimension of the particles of silver and tungsten is also 
manifested in the conductivity of thin films of metal, on which S. WEBER and 
E. OosTeRHUIS have just now published very careful measurements. (Proc. of the 
the Koninkl. Akad. v. Wetensch. Amsterdam 25 (1916), 606). 
For the appearance of a perceptible conductivity it will be necessary that the 
separate particles coalesce or that their distance has fallen at any rate below a 
certain minimum value. With a forming layer of metal this condition will be 
satisfied so much the sooner (ie. with a lesser average thickness) the smaller the 
dispersed particles are. W. and O. discovered that the conductivity of tungsten 
becomes perceptible with a thickness of 0,5 gg and that it shows a marked 
increase at 2,5 gp; for silver these figures were respectively 65 and 25 uz. 
