292 ANNUAL OF SCli:.\TJFIC DISCOVERY. 



three inches thick ; it, is of a spongy or fibrous appearance under the 

 water, but composed of Hat irregular crystalline planes or tables, with 

 regular angles and terminations, cohering or strung along upon each 

 other, and exceedingly white and beautiful . When the surface of 

 the water is free from ice, and its temperature at the freezing point, 

 that of the air being several degrees below the freezing point ; if 

 under these circumstances, there is none on the stones at sunset, they 

 are covered in the morning, after a clear cool night. This ice begins 

 to leave the stones in the morning, and before noon has all risen and 

 disappeared, often covering the whole surface for some time. The 

 depth of the ice below the surface of the water, as observed, was from 

 a few inches to three feet. 



The principle of this phenomenon is probably as follows. Satu- 

 rated solutions of some salts, as sulphate of soda, at a high tempera- 

 ture, may be cooled gradually at rest without depositing the salt. 

 The agitation of the cooled solution, on putting in a rod of glass, 

 wood, or metal, commonly, but not always, causes the deposition of 

 the substance. It is well known that \vater may be cooled in a still 

 vessel below 32 without freezing, but a little agitation produces con- 

 gelation of a part of the water in long fibrous or laminated crystals. 

 The stream of water is cooled to the freezing point, and by the cold 

 of the night its temperature is still further reduced. In this state the 

 caloric is more than saturated, and the stones and wood under the 

 water perform the part of the substances introduced into the solution 

 of salt, and the ice forms upon them. The quantity of anchor-ice 

 formed would be small, for an obvious reason. Every pound of water 

 frozen would evolve 142 of caloric, which would raise 142 pounds of 

 water one degree, or 71 pounds two degrees. Allowing the tempera- 

 ture of the stream to be reduced to 31 or 30, the congelation of a 

 relatively small quantity would thus prevent further congelation, 

 while the crystals of ice would be formed under water, where the 

 solid bodies, as stones and wood, arc. Considering how poor a con- 

 ductor wood is, it can hardly be supposed that anchor-ice is formed 

 on solid bodies merely because they are better conductors of caloric 

 than water is, and the more so, because they must have the same tem- 

 perature as the water. Rocks sometimes pass from a frozen bank, by 

 connection with which their temperature may be as low as 2CP, into 

 and under water, which congeals on them because they are so cold, 

 and thus forms solid ice. This is not a case of anchor-ice, nor has it 

 the form of that ice. Neither is that anchor-ice caused by a rock pro- 

 jecting above the surface and congealing the water into solid ice 

 around it. Prof. Dewey, in Silliman's Journal for Sept. 



DISCOVERIES OF GOLD IN 1850. 



In Indiana. AT the meeting of the Franklin Institute on May 17, 

 a letter was read from Prof. Wylie of the University of Indiana, an- 

 nouncing the discovery of gold in the beds of the rivulets in Morgan, 

 Jackson, Brown, and Green Counties of that State, composing a dis- 

 trict about 40 miles by 24. It is always in connection with a black 



