﻿184 



Mr. Horace H. Paolo on th 



iron and nickel wires, -12 mm. and *15 mm, diameter 

 respectively, soldered together at the junctions. The inner 

 junctions are equally spaced round the rim of the copper 



Fig, 1, 



vessel in the space formed by the enlargement shown in the 

 interior diameter of B. The junctions are kept apart and 

 insulated from the copper by paper soaked in molten 

 paraffin wax. In the space between the walls of B and C 

 the wires are supported by a paper cylinder stiffened with 

 paraffin wax. The idle parts of this annular space are 

 filled with cotton-wool to lessen conveetion currents. The 

 wires lead out through the vaseline under the rim of C, and 

 the 16 outer junctions are enclosed in four glass tubes, two 

 of which, F and G, are shown in the sketch. The four 

 junctions in each tube are equally spaced along the tube so 

 as to obtain the average temperature of the ice. Ordinary 

 flexible leads are used and for about six feet are embedded 

 in the ice, the arrangement of protecting tubes being the 

 same as that described in a previous paper (Phil. Mag. Feb. 

 1910). The ends of the flexible leads are brought under 

 the rim of and soldered to a pair of iron wires of the 

 couple, the connexions being close together under the bottom 

 of B and inside the ring E. 



For a description of the reversing- "key and galvanometer 

 arrangements and of the system of ice vessels emploved 

 reference mu*t be made to previous papers (Phil. Mag. Feb. 

 1010 and Jan. 1911). 



The use of such a large number of junctions, although 



