ISO ROYAL SOCIETY OF CANADA 



lower in the scale. I show in Fig. 1 a diagram of the ether spectrum, 

 as we now Imow it, which illustrates very well the relation of the 

 known ether waves. 



Terrestrial Eadtation. 



It is probable that the radiation from the earth's surface consists 

 of a large proportion of the long heat waves. 



On a clear, cold night in an arctic winter the character of the 

 radiation into space at the absolute zero of temperature ( — 373° C.) 

 must be of much interest. 



The problem is of importance in considering the formation of ice 

 in our lakes and rivers, but on account of the difficulty of applying 

 any of the known laws of heat radiation to it, the matter is exceedingly 

 difficult to treat at all completely. 



Thus, it was shown by ]\Ielloni and Tyndall that water and ice 

 are both opaque to the radiation from a low temperature source, such 



THERMAL ^^^^H LLECTRICAL 



O-lii OtuUBu nULL 3mm lOOTum 



Fig. 1. Spectrum of Ether Waves, the dark Portion Showing the 

 Unexplored Region. 



as a copper ball heated to 400° C. or to 100° C. At the same time, 

 we know that ice formation goes on in a river through quite large 

 masses of water and ice, when clear and free from surface snow. 

 Anchor-ice forms at the bottom of a river, under circumstances 

 which leave no doubt that radiation has given rise to its production. 

 The absorption of the heat waves by water has been traced by Eubens 

 and Aschkinass in 1898, to waves as long as 60 jw. It is likely then 

 that the radiation which is responsible for the production of anchor- 

 ice must be beyond 60 ^, and well into the unexplored region. Drude^ 

 has shown that water is opaque to electrical waves of 9 centimetres, 

 but transmits waves of 60 cm. in length. A region of transparency 

 must be then betAveen waves -060 mm. and 90 mm., to be followed 

 by another at 600 mm. The radiation from the earth consists probably 

 of a large proportion of the waves in the unexplored region between the 

 longest thermal and shortest electrical waves yet measured. 



Experimental. 

 As a continuation of my studies of anchor-ice formation it was 

 decided to determine, if possible, the amount of penetration of the 



^Drude, Wied. Ann. 65, 499 (1898). 



