256 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



bars H and H^ penetrating it. The spring pressing on the top of C, 

 the compression of which can be regulated by the knurled brass nut 

 D, is to keep the screwed part of the centre spindle up into the nut, 



BBA-iSBAj. 



iVb&j 



X, 



PHOSPV 

 BR( 



l3R.vfc, t O ccv is Ptmm 



-<S4 BA 



- ^' V* 



5QO TEETM So P lEftD 5Q 



Fro. 53. 



Fig. 54. 



