44-3 



any desired position by the use of slender rods of wood, without 

 any change of temperature in the water. If brought near to each 

 other and then left unrestrained, they separated, returning to their 

 first position with considerable force. If brought into the slightest 

 contact, regelation ensued, the blocks adhered, and remained ad- 

 herent notwithstanding the force tending to pull them apart. They 

 would continue thus, even for twenty-four hours or more, until they 

 were purposely separated, and would appear (by many trials) to 

 have the adhesion increased at the points where they first touched, 

 though at other parts of the contiguous surfaces a feeble thawing 

 and dissecting action went on. In this case, except for the first 

 moment and in a very minute degree, there was no pressure either 

 from capillary action or any other cause. On the contrary, a 

 tensile force of considerable amount was tending all the time to 

 separate the pieces of ice at their points of adhesion ; where still, I 

 believe, the adhesion went on increasing a belief that will be fully 

 confirmed hereafter. 



Being desirous of knowing whether anything like soft adhesion 

 occurred, such as would allow slow change of position without sepa- 

 ration during the action of the tensile force, I made the following 

 arrangements. The blocks of ice being moored by the threads 

 fastened to the lowest corners, stood in the water with one of the 

 diagonals of the large surfaces vertical ; before the faces were 

 brought into contact, each block was rotated 45 about a horizontal 

 axis, in opposite directions, so that when put together, they made a 

 compound block, with horizontal upper edges, each half of which 

 tended to be twisted upon, and torn from the other. Yet by placing 

 indicators in holes previously made in the edges of the ice, I could 

 not find that there was the slightest motion of the blocks in rela- 

 tion to each other in the thirty- six hours during which the experi- 

 ment was continued. This result, as far as it goes, is against the 

 necessity of pressure to regelation, or the existence of any condition 

 like that of softness or a shifting contact ; and yet I shall be able to 

 show that there is either soft adhesion or an equivalent for it, and 

 from that state draw still further cause against the necessity of pres- 

 sure to regelation. 



Torsion force was then employed as an antagonist to regelation. 

 The ice-blocks, being separate, were adjusted in the water so as to be 



