266 ANNUAL OF SCIENTIFIC DISCOVERY. 



CURIOUS PHENOMENA OF ICE. 



At the Montreal meeting of the American Association, Professor Henry 

 presented a paper entitled, " Some Phenomena of Ice." 



In the commencement he stated, that if anything strange or curious occurs 

 in any part of the country, the Smithsonian Institution was quite sure to hear 

 of it, and in this way more questions were propounded to its officers than 

 wise men could always answer. A year ag'o last winter, on a very cold day, 

 a countryman called upon him and stated that he had come twenty miles to 

 show him something which he thought very extraordinary. The article was 

 a common tin milk-pan filled with frozen water. On the top of the ice, ris- 

 ing in its centre, was a strange formation, created without apparent cause, 

 consisting of a crystal of ice protruding in a direction ohlique to the general 

 surface, in shape something like an isosceles triangle, with its sides slightly 

 curved and corrugated, and its centre hollow. The countryman stated that 



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the pan of water had stood in a cold entry way over night, where it had not 

 been disturbed or agitated in freezing, and he desired to know what had 

 caused it to assume this remarkable form, shooting out a pyramid from its 

 centre. 



Professor Henry was unable at the time to answer satisfactorily, but had 

 a drawing made of the object, and laid it aside for future investigation. 

 Last winter he received another communication, making inquiries in relation 

 to extraordinary workings of ice and the ground which took place at that 

 time. Reflecting upon the latter phenomenon, an explanation of the milk- 

 pan curiosity also occurred to him. It was well known that, in the process 

 of the solidification of melted metals, and the freezing of water, the crystals 

 are produced in the direction of the surface from wh*ich the heat escapes. In 

 the freezing of the water in a vessel of the milk-pan shape, the crystals ran 

 across in nearly horizontal lines, crossing each other at an angle of sixty de- 

 grees. The water freezing first from the sides and bottom of the vessel, left 

 in the centre and top a triangular space, which the yet unfrozen but still ex- 

 panding water found too small for it. This unfrozen water was forced up 

 by hydrostatic pressure, above the frozen surface surrounding it, and held by 

 capillary attraction in this position, until its edges became a ring, or rather 

 a corrugated base section of the future triangular pyramid. When this be- 

 came frozen, the process of solidifying, still progressing below, continued to 

 force up the water, until another and another section was raised, and the 

 column entirely completed. 



Water in the act of congealing expands ; but after it has once been frozen 

 into ice, it follows the law of all solids, contracting with cold and expanding 

 with heat. Indeed it has been proven to shrink even more than any other 

 solid. This explains the cracking of ice on the lakes, with loud explosions, 

 in very cold weather the ice shrinking and parting. The cracks always 

 occur in the place of least resistance, as, for instance, in the narrowest part 

 of the body of water frozen over. The professor stated further, that the 

 crystals formed on the surface of large bodies of water in the process of 

 freezing were nearly perpendicular, the coating surface being that exposed to 



