876 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



at the corner of the stage in the same manner as the stage forceps. 

 The pointed end of a glass dipping-tube answered the purpose 

 admirably. When it was desired to pass sparks vertically through 



Fig. 207. 



an object in focus, a glass stage-plate was used. This consisted 

 simply of two pieces of glass, about an inch longer than the brass 

 stage, cemented together with a wire between them, the point of which 

 turned up at right angles in the centre of a hole drilled through the 

 upper plate. The other terminal, mounted as above, could then be 

 adjusted over it in any required position. A small induction coil was 

 used for the purpose, giving about a 1/2 in. spark with a single 

 bichromate cell. If a Leyden jar was placed in the circuit, discharge 

 sparks of much greater size and brilliancy were obtained, giving 

 beautiful effects when viewed through the micro-spectroscope. " Cau- 

 tion is desirable in conducting experiments of this kind, since 

 manipulation, duriag observations which engage the attention closely, 

 is apt occasionally to produce very startling results." 



Apparatus for watching the phenomena that animals subjected 

 to great pressure present.* — As previously recorded,! ^^- P- Kegnard 

 has experimented on the conditions of life at high pressure. With 

 apparatus designed by M. Cailletet, he has subjected aquatic animals 

 to enormous pressure, such as prevails in the depths of the ocean, 

 and has examined the results when those inhabiting the surface are 

 suddenly placed at great depths. 



* Comptes Rendus, c. (1885) pp. 1243-4 (1 fig.), 

 pp. 399-400 (2 figs.), from ' La Nature.' 

 t See this Journal, iv. (1884) p. 362. 



Nature, xxxii. (1885) 



