APPENDIX 



161 



which accordingly moves in a horizontal direction, corresponding 

 with the vertical descent of the sensitive plate. In this manner a 

 simultaneous record may be obtained, e.g., of a series of muscular 

 contractions along with the negative variations of the muscle - 

 current ; or, again, of contraction and heat (by means of a thermo- 

 galvanometer) ; or of the contractions of a muscle and the negative 

 variations of its nerve ; etc., etc. 



LARGE DARK ROOM 



W/////////S 



FIG. 64. 



In the Physiological Laboratory of the University of London 

 the apparatus described above is disposed according to the following 

 plan, so as to afford two complete working tables with two pairs of 

 galvanometers and accessory apparatus : 



The galvanometers G l to G 5 are placed on brackets along one 



