14 l&Keevor's Voyage to Hudson's Bay. 



On the river Wharfe, wear Otley, in the West Riding of 

 Yorkshire, is a weir, or mill-dam, the structure of which is 

 of hewn stone, forming a plane, inclined to an angle of from 35" 

 to 50 fronting the north, and extending from W. to E. to 

 the length of 250 or 300 yards. When the wind suddenly 

 shifts from Sk W. to N. W., and blows with great impetuosity, 

 accompanied with severe frost and heavy falls of snow, the 

 stone which composes the weir soon becomes encrusted with 

 ice, which increases so rapidly in thickness, as in a short time 

 to impede the course of the stream that falls over it in a toler- 

 able uniform sheet, and with considerable velocity: at the 

 same time the wind, blowing strongly from the N. W. contri- 

 butes to repel the water, and freeze such as adheres to the 

 crust of ice when its surface comes nearly in contact with the 

 air. The consequence is, that in a short time the current is 

 entirely obstructed, and the superincumbent water forced to 

 a higher level. But, as the above-mentioned causes continue 

 to act, the ice is also elevated by a perpetual aggregation of 

 particles ; till, by a series of similar operations, an icy-mound, 

 or barrier, is formed so high as to force the water over the op- 

 posite shore, and thus produce an apparent inundation. But 

 in a short time the accumulated weight of a great many thou- 

 sand cubic feet of water presses so strongly against the bar- 

 rier, as to burst a passage through some weak part, through 

 which the water escapes, .and subsides to its former level, 

 leaving the singular appearance of a wall or rampart of ice, 

 three or four feet in thickness, along the greatest part of the 

 upper edge of the weir. The ice composing this barrier, 

 wnere it adheres to the stone, is of a solid consistency, but the 

 upper part consists of a multitude of thin lamina 1 , or layers, 

 resting upon each other in a confused manner, and at different 

 angles of inclination, their interstices being occupied by innu- 

 merable spiculae diverging and crossing each other in all di- 

 rections. The whole mass resembles in its texture the white 

 and porous ice, which may be seen at the edge of a pond, or 

 small rill, where the water has subsided dijring a frost." $w 

 Journal of Science and Arts. No. X. 



The explanation of this curious phenomena is* certainly very 

 difficult, and would appear to argue somewhat against tlio 

 long-received opinion of the diminished specific gravity of 

 water after being cooled down beyond the temperature of 30. 

 As there has been as yet no satisfactory theory offered on the 

 subject, I shall beg leave to state, in very few words, in 

 what manner I conceive this deposition to take place. While 

 reading Dr. Garnet's paper, I was very forcibly struck with 

 the peculiar circumstances in which he states this icy incrus- 



