14 ART. 12. — H. HIROBE I ON THE FUSION SURFACES OF THE 



insertion of the thermo-junction, and tlie fourth for adding phenol 

 or chlorobenzene to the solution. D is a hand-bellows which is 

 used to force in air in order to cool the inner tube. ^ is a 

 piece of thick felt and serves to keep the inner tube in position. 

 L is thin insulated manganine-wire wound round the stirring 

 rods, through which an electric current is passed to prevent the 

 cooling of the rods from the outside. 



When this precaution is not observed, the naphthalene is 

 apt at higher temperatures to sublime round the rods ; and 

 moreover it is difficult to maintain the state of superfusion 

 before stirring the liquid, since naphthalene crystalises rapidly 

 round the cold copper rods. K is an ebonite piece. / is a 

 caoutchouc tubing connecting the stirrer and the rod hanging 

 from an excentric wheel which is kept in motion by an electric 

 motor. The caoutchouc tube ])roved to be very useful, since 

 by shortening or elongating it we could very easily adjust the 

 height to which the stirrer was to be lifted ; so that it might 

 correspond to the amount of liquid contained in the tube. / 

 is the stirrer of the bath kept rotating by a hot air engine. 

 E is a temperature regulator with a hollow cylindrical reservoir 

 containing toluene in the space between its double walls, so that 

 the surface exposed to the liquid of the thermostat is large in 

 comparison to the capacity of the reservoir. The temperature 

 of the bath must be varied from time to time as the fusion 

 point descends, and it was absolutely necessary to have a sensi- 

 tive and rapidly adjustable regulator to economise time. The 

 shape given to the regulator was found to ausw^er the purpose 

 very well. It required only two or three minutes before w^e 

 could be assured that the toluene within it had attained the 

 temperature of the bath, and there was no fear of breaking the 



