a gelatin gol of wliich tlic water content is 'M.') '/( or less 

 never freezes at aii\' Icnipcrature. 



The followini^- table «;ives, in a com})r('lH'iisive form, the 

 conclusions of ^loran and Hardy : 



3. Coagulated Material. Prillieux (1869b) described an 

 exudation of ice from the white and from the yolk of a 

 boiled egi>,- when the latter was put to freeze under a cover, 

 after the shell was removed. There was a layer of ice 1 

 mm. thick outside the white, and another of about the same 

 thickness between the white and the yolk. The white was 

 itself divided into several concentric layers of unfrozen, 

 soft albumin, separated by shells of ice, some of whicli were 

 about 1 mm. thick. The ice shells consisted of small ice 

 columns with their axis perpendicular to the surface of 

 the shells. There were tiny air bubbles along the axis of 

 the columns. 



4. Porous uiafcrlal. If the water which freezes out of a 

 liciuid is hindered in its withdrawal not only by the forces 

 which hold it in solution or in suspension l)ut also ])y capil- 

 lary or osmotic forces, we should expect some dilference 

 in the form of the resulting crystals, their state of aggre- 

 gation and their velocity of formation. 



Rigaud {Londou-Ed'tuh. Phil. Mag., 2, UK), 1853) de- 

 scribed a particular type of exudation of ice from the 

 mortar of a stone wall. A plate of ice covered the wall. 

 It consisted of juxtaposed ice columns which grew parallel 

 to eacli othci- and pcrjjeiidicular lo the surface from which 

 they arose. The columns were oi' all sizes u]) to several 

 centimeters in length. 



