^ 



The adjusting- device R is 

 represented on a somewhat 

 larger scale, in tig. 2h ■ it is 

 tixed in position over a 

 resistance-furnace, and con- 

 nected with the capillary 

 tube made of the platinum- 

 i-liodiuin-alloy and the thermo- 

 element F. In this drawing 

 the rectangular support with 

 I lie spirals ^r are also plainly 

 discernible, together with the 

 hollow water-screen J, in 

 which a current of cold water 

 is continually circulating. 

 Thi« adjusting device consists 

 of two semi-circnlar parts 

 about 40 cm. in diameter. 

 One part is permanently 

 attached to the apparatus R, 

 the other can be fitted to it 

 by means of pins and short 

 tubes. The latter part has a 

 circular glass- window^ where 

 upon the totally reflecting and 

 movable (around a horizontal 

 axis) prism E is placed. By 

 means of this prism the be- 

 haviour of the liquid in the 

 furnace can l)e observed and 

 controlled at every moment. At 

 temperatures over 1000° C, 

 coloured green glasses are 

 Fig- 2/^. inserted in front of the prism. 



With the protection of the waterscreen J it proved possible, to use 

 the manometer even at temperatures of 1650° C, without any 

 disturbance from the heat-radiation of the furiuice. The furnace B 

 is a platinum- (or nichrorae-) resistance furnace of the usual type '); 

 it has an inside wound heating-coil, and can be heated with a 

 central tube of alundum inside, up to 1400° C, and without such a 



1) F. M. Jaeger, Anleitung u.s.w. (1913). p. 36. 



