841 



apparatus consisted of two non-silvered vacuum glasses — the out- 

 side being used for air and the inside for iiydrogen in the usual 

 manner. Fig. 1 shows the shielded box B into which ' circuit Nr. J 

 was put. C is the top of the inductance coil shield, L is the lid of 

 the box, P is the packing. Under the hood circuits Nr. 2 and Nr. 3 



Fig. 1. 



are arranged as shown. The amplifier A is on the table to the 

 right. The small condenser K (used at a place where it has 

 313 [m f capacity) is connected in series with a larger fixed con- 

 denser (capacity 2847 nnf) between the filament and grid of 

 circuit Nr. 2. The rod R 270 cms. long controls the motion of A', 

 being attached to a screw adjustment S. Adjusting S changes the 

 frequency of circuit Nr. 2 by small amounts. On fig. 2 a view 

 is given of the inside of the box B, the shield of the coil 6' 

 and its windings W being plainly visible. The shield segments 

 are connected by the wire D and when the lid is lowered tiie 

 wire D is connected to the box shield by a short wire and a clip. 

 The windings of the coil IF are supported by a piece of glass 

 tubing to which they are well fastened with paraffine. The upper 

 part of the shield is made of pasteboard tubing thoroughly boiled 

 in paraffine and hardened by several coats of shellac. The filament 

 and plate batteries are also shown on this picture. The filament 

 rheostat which is shown on the right wall has been short circuited 

 in the final measurements so as to eliminate fluctuations in the 



56 



Proceedings Royal Acad. Amsterdam. Vol. XXVI. 



