PLATE III. 



Fir,. 5. Carbonic acid apparatus. A. Bottle containing hydrochloric acid. M. Bottle containing fragments of 

 inarlile on a stratum of broken glass. v - Wash-bottle. H. Object support, fig. 16. . T-tul>e which communicates 

 with the gas app;ir;itns by the tube F, which is guarded by a clip, and in the opposite direction with H. By its stem 

 it is in direct communication with the mouth of the operator by a tube on which there is also a clip- Wlien the 

 first .dip is closed. carlMinic add collects in M and drives back the hydrochloric acid into A; a current of air can 

 then lie drawn through and H. If the clip on the mouth-tube is closed and that on F opened, carbonic acid 

 passes through H. p. 16. 



FIG. 6. Microscope stage on which the object-glass is held in position by Strieker's electrodes. Each electrode 

 is insulated by being screwed into an ivory knob which is let into the Kfcige plate of the microscope. The electrodes 

 are connected (with the inti-rix.sition of a key) with the secondary .'oil of a Im Hois Kcymond's induction appa- 

 ratus. The key is represented open. The upper surface of the object-glass is covered with tinfoil, leaving a space. 

 6, for the reception of the object, p. 17. 



