IJ 45 



to 8 hours) at room temperature was partially covered with Canada- 

 balsam when still in the vacuum. 



Notwithstanding' the use of a tungsten auxiliary-lamp the vacuum 

 was found to be but fairly good at the expiration of the sublimation. 

 With access of air the tint of the greyish-black precipitate shows no 

 modification. 



In the part protected with Canadabalsam hardly anything is to 

 be seen, no connected network and but few separate particles. The 

 latter are often in a circular position, inside we find larger particles, 

 which seem to have grown at the expense of the others. By the 

 side of these we also notice bifurcated larger particles, typical initial 

 forms of the crystalline state. 



Some other lamps, in which a precipitate had been similarly 

 formed, revealed a similar image: various separate particles, but no 

 mosaic and even no Tindalleffect. 



Finally we heated in a last lamp, and after the formation of the 

 sublimate and when still in the vacuum, a single spot by means of 

 a thin Hame to such an extent, that the glass began to bend inwards 

 (450°). The result was that the tint of the precipitate became much 

 lighter. When the lamp was opened after refrigeration the heated 

 places of the precipitate showed under the microscope a very fine 

 and weak, but quite perfect network of ultramicrons, whereas the 

 non-heated spots only showed many separate particles. The colour 

 of the deflected light of the ultramicrons was, when using Huygkns' 

 ocular, pale-grey metallic. 



Hence with iron as well it appears that the principal part of the 

 metal-precipitate is present in an optically insoluble form, which by 

 means of heating is brought to segregation in ultramicrons. 



^11. Carbon. 



Carbon, as well, gave a black, uncoloured precipitate, optically 

 insoluble. 



\ 12. Copper. 



Here arise again beautifully-coloured precipitates, as we observed 

 with Au and Ag; they show great similarity especially with those 

 of Au. The thinnest layers are yellowish red, then follows red and 

 blue, at last blueish-green and finally the reflection-colour of metal- 

 lic copper sets in. 



The ultramicroscopic image too, bears a close resemblance to that 

 of gold. 



There are many separate particles and in between a weak but 



