Section III., 19C6. [ 65 ] Trans. R. S- C. 



VI — Anchor-Ice formation from the standpoint of the Radiation 

 Theory, together with some early memoirs on Ground-ice. 



By Howard T. Barnes^ D.Sc, 



Associate Professor of Physics, McGill University. 

 (Read May 23, 1906.) 



The form of ice which has attracted the most attention of all 

 the forms to be met with in Nature is that known in this country 

 2i? Anchor Ice. As its name implies it is ice which is found attached 

 or anchored to the bottom o£ a river or stream. It seems to have 

 been observed in nearly all countries where river ice is formed and 

 goes by the name of ground-ice, bottom-ice, ground-gru, a name given 

 it by the inhabitants of Aberdeenshire, and lappered-ice by the common 

 people of the South of Scotland, who apply the epithet to the natural 

 coagulation of milk. In France it goes by the name of glace-du-fond, 

 and in Germany as Grund-eis. The French-Canadian name for it is 

 moutonne ice, from its resemblance to the white backs of sheep at rest. 



The phenomenon of ice forming on the bottom of rivers has been 

 known for a very long time, and although the majority of the early 

 philosophers of France denied its existence, it was perfectly well known 

 to every peasant. 



In 1788 M. Beaun wrote several papers to establish the existence 

 of ground-ice from his personal observations. He reports that the 

 fishermen on the Elbe used to find the baskets which they let down 

 into the river for the purpose of catching eels, were often, when brought 

 up to the surface, incrusted with ice. Anchors used for mooring their 

 boats when lost during the summer, frequently appeared in the follow- 

 ing winter, being raised by the mass of ice which had formed about 

 them. Their signal buoys sometimes became displaced from the raising 

 of the large stones by the ground-ice and caused great inconvenience. 



M. Desmarest, a member of the French Academy of Sciences, was 

 among the first of the scientists to make observations on the formation 

 of ground ice. He reports having observed flakes of ice, formed at the 

 base of running streams, increase in thickness five or six inches in 

 a single night. 



In " Picturesque Views of the River Thames," published in 1792, 

 Ireland speaks of the ground-ice of that river, remarking, " The water- 

 men frequently meet the ice meers, or cakes of ice, in their rise, and 



Sec. III., 1906. 5 



