434 Proceedings of the Royal Society of Edinburgh. 



2. On the Theory of Waves. Part II. By Professor Kelland- 



3. Analysis of Berg-Meal from Umea Lapmark. By Dr 

 Traill. 

 Professor Traill gave an account of the composition of a sub- 

 stance brought under the name of Bcrg-Mnal from Swedish Lap- 

 mark by Mr Laing in 1838. It was found just under a bed of de- 

 cayed mosses, forty miles above Degersfors, in Umea Lapmark. 

 When examined by the microscope, it was found to consist of several 

 species of minute organic remains, which Ehrenberg has consi- 

 dered as the siliceous skeletons of infusoria; the largest measured 

 from 0.006 to 0.0005 of an inch. On analysis, Dr T. obtained 

 22 per cent, of organic matter, entirely destructible by a red heat; 

 and he found the snow-white residue, which still retained the mi- 

 croscopic forms, to consist of 71.13 of silica, 5.31 alumina, and 

 0.15 oxide of iron. He considers the organic matter and the si- 

 lica, as the essential ingredients, and the others probably as ac- 

 cidental. As a mixture with food, the quantity of organic mat- 

 ter in the Berg-Meal gives it a preference over the steatites and 

 clays used for a similar purpose by some rude tribes. 



February 1. — Dr Abercrombie, V. P. in the Chan*. The 

 following communications were read : — 



1. Oh the force of Solar Radiation in the Arctic Regions, by 



Dr Richardson. Communicated by the Secretary. 



2. An attempt to reconcile the Theories of the Debacle and 



the Action of Glaciers, in accounting for the Distribution 

 of Erratic Blocks. By Sir G. S. Mackenzie, Bart. 



The author commenced by alluding to the disposition of oto- 

 logists to draw conclusions of a general nature too hastily from the 

 facts observed by them, illustrating this remark by referring to the 

 various opinions successively promulgated, not only by geologists 

 generally, but even by the same geological writer, on the subject 

 of the till or boulder clay, the gravel, and sand, by which Great 

 Britain is every where more or less covered. At one period, all 

 these superficial deposits were referred to the action of water alone ; 

 now it is the fashion to explain them by the agency of o-laciers. 



In treating of the appearances presented by these deposits, the 

 author observes, that those which at first sight might be thought 

 to indicate tranquil deposition from water, might in reality be due 



