On the Formation of Bottom Ice. 407 



little known, that the ice formation in this sea scarcely ever 

 takes place in the same manner as in inland lakes, but generally 

 through round lumps of ice which rise up from the deeps, and 

 freeze together on the surface. To Professor Nilsson are we 

 indebted for the following remarks : — 



ON THE POBMATION OP ICE OEE KEELLEN POINT, ON THE 

 SOUTH COAST OP SWEDEN. 



In the salt sea, ice is very seldom formed on the surface of 

 the water (the sea is generally too rough and agitated by wind 

 and currents), but usually in the following manner: — Small 

 thin and flat plates of ice, of different form and size, float up 

 often in large quantities to the surface, where, . crushed 

 and broken into small pieces, either through the dashing of 

 the waves or the strength of the currents, they are ground 

 against each other till the particles become small, and at length 

 freeze together to round or flattish lumps of ice, of different 

 sizes, which, as soon as the water becomes tolerably still, cohere, 

 and form a compact rough covering of ice. Only close to the 

 shore, in shallow water of four or six feet deep, and in calm 

 weather, is salt water ice formed, as in still inland lakes, on 

 the surface, by what is called ". glanskis." 



These plates of ice are very variable in form and size, but 

 always as thick in the circumference as in the medium point. 

 They have a diameter of from one to five inches, but a thick- 

 ness of never more than two lines. Their form is generally 

 round, but sometimes, especially in the smaller pieces, which 

 have probably been crushed and broken, irregular and angular. 



It is not known at what depth these plates of ice are formed. 

 They are seen first when they come up to the surface, glisten- 

 ing and dancing in the smooth water in the wake of the boat. 

 In clear and still weather they can be seen at the depth of 

 two feet at least, rising up to the surface in pieces of different 

 sizes, in incredible quantities. But we do not fancy that 

 the above-named ice formation takes place at a very great 

 depth. We often see, in a sharp frost, stones and branches of 

 sea-weed covered with ice like the hoar-frost on trees, and the 

 nearer it is to the surface of the water the broader and larger 

 is the covering of ice, which, however, does not extend lower 

 down than about four feet from the water's edge. But 

 fishermen say that it can freeze at even a greater depth, 

 oven to eight feet ; for twenty years since, on a very cold 

 night, a vessel filled with live cod-fish was sunk in at 

 least seven feet of water, and in the morning the fish were 

 found frozen to death, and, moreover, that they have seen 

 stones and sea- weed covered with a coating of ice even at a 



