That bodies of running, water, the surface of which solidifies when exposed to a diminished temperature, should have a tendency to congelate in their sheltered depths, seems an anomaly which demands inquiry and explanation; and accordingly each of the above-mentioned writers has raised an hypothesis more or less probable, to account for the phenomenon. Dr. Farquharson would attribute it to the radiation of heat from the bottom, as dew is formed by radiation from the surface of the earth; but a consideration of the supervening obstacles to radiation—a body of moving water thickly coated with ice and even snow—destroys the plausibility of his theory. That of Mr. Eisdale, that the frozen spiculæ of the atmosphere falling into the water become nuclei, around which the water at the bottom freezes, seems merely frivolous. The explanation of M. Arago is more satisfactory, viz. that the lower currents of water being less rapid in motion than those intermediate, or at the surface, congelation may be expected at a lower temperature (say 32° Fahr.), the process of crystallisation being favoured by the pebbles, fragments of wood, and the uneven surface of the river's bed. After all, however, the phenomenon has been but imperfectly investigated under its various manifestations, and its real cause probably remains yet to be discovered.
William Bates.
Birmingham.
For an explanation of this occurrence, I would refer J. C. E. to Whewell's Astronomy, Bridgewater Treatise.
Unicorn.
CHARACTER OF ALGERNON SYDNEY.
(Vol. v., pp. 426. 447.)
Your two correspondents C. E. D. (p. 426.) and C. (p. 447.) appear to have read Mr. Hepworth Dixon's Query about Algernon Sydney either very hastily or very carelessly. Yet it seems to me plain enough. There is not one word in it about Barillon or Dalrymple; no inquiry about the home life of Sydney. As every one knows a great part of his time was spent abroad, it is probable Mr. Dixon thinks that anecdotes and allusions to so conspicuous a person may occur in the cotemporary letters and memoirs of France, Germany, Italy, &c., and he asks for references to any such anecdotes or allusions as may have fallen in the way of readers of "N. & Q." Surely this is explicit. But what has Dalrymple or Mr. Croker to say in answer to a question about Sydney's way of life when abroad? That, as I take it, was the point, and a general discussion as to the character of the author of the Discourses on Government is à-propos of nothing. As the subject has been opened, and as I know of none more interesting in the whole range of English history, I cannot refrain from at least entering one protest against C.'s description of the "illustrious patriot" as a "corrupt traitor of the worst class."
That Mr. Dixon is not single in his admiration of the character of Sydney I could quote many "instances," from our late prime minister downwards. But the title "illustrious" can scarcely be denied to a man who, besides being of the best blood in England, played a leading part in the Revolution, and was one of the closest thinkers and most masculine writers our language has to show. What makes a man illustrious? Birth, commanding position, intellect, learning, literary genius? Sydney had them all. But C. thinks