1077 



the wall. After the fiiiisliiiig of the first burning we see namely on 

 the bnlb wall already a slight bnl detectable black colonr. 



§ 5. SuDiinari/. 



1. By investigations in I he spectrographic way and by determina- 

 tions of the changes in the gas pressnre it was shown that with 

 the aid of electric discharges phosphorus vapour can be brought to 

 a rapid reaction with all gases except with the inert gases. 



2. Tlie action, obtained in the glow-lamp with phosphorus, can 

 also l)e ol)served with silicates. 



3. At high temperatures silicates undergo a fractional distillation. 



4. When tungsten and silicates are in contact at a high tempera- 

 ture a reaction takes place between these substances, by which 

 alcaline-metal is liberated. By means of this we can in the same 

 way as with phosphorus obtain the perfect removal of rest-gases (in 

 glow-lamps) with the aid of electric discharges. 



5. The reaction between tungsten and glass makes the use of 

 tungsten for leading- in wires possible. 



6. Ata rapid cooling of the vaporized silicate a product is formed 

 in an undercooled state, which has other properlies than the normal 

 glass. The thus obtained coJidensate can decrease the blackening of 

 the wall in the glow-lamp, due to the vaporized tungsten. 



7. A similar reaction as with silicates is obtained by the applica- 

 tion of aluminales, calcium-phosphate, magnesium-oxide, silicium- 

 dioxide. In the case of this last oxide we come to the conclusion 

 that a trace of free Si is formed; only quantities of the order of 

 magnitude of 0,001 mg. Si show a detectable activity. 



Finally the author gladly seizes the opportunity to mention the 

 kind help of Dr. G. L. F. Philips, w.i., who enabled him to 

 execute these investigations. 



Eindhoven, Laboratory of the N . V. Phiiip.s's 

 Glowlamp-ivorks . 



