206 Profs. E. Rutherford and H. T. Barnes on the 
The differences were observed on a scale-and-vernier reading 
to the 45 of a millimetre. The greatest difference observed 

a ANAL 

Fig. 2,—Differential Inner-coil Platinum Thermometers in Water-bath. 
amounted to somewhat over 7 millimetres, and corresponded 
to a difference of temperature of about 3,° C., and readings 
could be made with certainty down to one-hundredth of this. 
We did not aim to obtain quantitative measurements of the 

