688 
supplies us with a method pre-eminently fit to discover transition 
points in metals, both on account of its accuracy and quickness, 
this was not yet known. 
This we found in the following research, which was undertaken 
with a purpose to discover the above-mentioned transition point also 
by a thermo-electrie way. For this purpose we first examined what 
metal combined with tin promised a good result. For reasons which 
will further be set forth in the theoretical discussion of this method, 
iron was chosen as second metal. 
The investigation of the electro-motive force of this element at 
different temperatures gave the following result: 
IRON-TIN. 
eae 
Temperature E. F. in milli-Volts 
139.89 1.30 
146.8° 1.31 
172.4° 1.39 
183.59 1.46 
196.69 1.63 
199,20 1.69 
204 :0° 1.72 
208.4° 1.74 
212769 1.79 
after sudden cooling 
180.09 1.65 
180.09 1.59 
180.09 1.53 
180.09 1.46 
180.0° 1.43 
170.4° 1.38 
When we represent this result graphically, we get fig. 1, from 
which we see that the transition point appears very clearly, and 
lies at 200°.2, which result is in perfect harmony with the extra- 
polated value which followed from the dilatometer-examination of 
