RADIATION IN ABSOLUTE MEASURE AT VERY LOW TEMPERATURES. 351 
necessary to alter the arrangements considerably, in order to make them suitable for 
low-temperature work. 
5. The bodies used in these experiments for radiation purposes are solid copper 
globes, 4 centims. in diameter. These globes, and the enclosure in which they are 
suspended, were used in many earlier experiments on radiation at high temperatures; 
and the main parts of the apparatus used then and of the present apparatus are 
essentially the same. As has been already mentioned, however, modifications had to 
be introduced, owing to the low temperature to which the enclosure was subjected. 
6. Referring to the general sketch of the apparatus, fig. 1, and to fig. 2 : at the centre of 
a spherical copper shell cia, 8 centims. in diameter, a copper globe g is suspended. The 
