458 



cussion on regelation, to which these notes are intended to be sup- 

 plementary. A most remarkable deficiency, however, still remains, 

 apparently, in our knowledge of this substance : Water in the 

 vitreous condition Ice-glass has never been observed. While 

 we know the antithetical vitreous state of so many different cry- 

 stallized substances minerals produced by heat, salts deposited from 

 aqueous solution, neutral bodies of organic origin and have great 

 reason to believe that that antithetical condition to crystallization 

 is universal, we have no knowledge of it in relation to water or ice. 

 My own attention has been awake to the subject, without success, 

 for many years. It would seem to be scarcely within the bounds of 

 possibility that the glassy state of water, if possessing what we term 

 solidity, should not, ere now, either have been observed in nature, or 

 have occurred and been recognized in experimental research*. 



I now venture to submit the inquiry, Does this apparent deficiency 

 in our knowledge exist because to use language recently introduced 

 into physical science the homologue of the glassy state of water is 

 not what we ordinarily term solid because the state of water cooled 

 below 32 but still liquid is in fact the state which corresponds to 

 the vitreous condition of other bodies, and to the physical nature of 

 perfect ordinary glass ? Is the one simply a case of potential soli- 

 dity, and the other of the confluent or equivalent state of arrested 

 liquidity ? 



It may be said that the homology which is here endeavoured to be 

 established between liquid water below 32 and glass, is a forced one. 

 That, in relation to each other, these are extreme cases is perfectly 

 true ; but intermediate terms of the series are not wanting, and some 

 of them are supplied by sulphur and phosphorus, and in a remark- 

 able manner by selenium. All these bodies, when melted, may be 



* The crushed fragments of the ball of ice cooled in carbonic acid and ether, 

 in Prof. Tyndall's experiment already mentioned, which " remained white and 

 opake as those of crushed glass," were still, he informs me, perfectly crystalline, 

 resembling fragments of quartz. 



The " points of analogy between the molecular structure of ice and glass " 

 noticed by Mr. Drummond (Phil. Mag., August 1859, S. 4. vol.xviii. pp. 102-103) 

 do not involve the physical condition of those bodies, but relate merely to the 

 resemblance of one crystallized substance (ice) to another (Reaumur's porcelain), 

 and of both to a third body (bottle- and window-glass), which, from its optical 

 characters, is inferred I think inconsequentially to have assumed a state pre- 

 paratory to crystallization. 



