ON INORGANIC AND ORGANIC SUBSTANCES. 313 



Notice of Experiments in Progress, at the desire of the British 

 Association, on the Action of a Heat of 212° Fahr. when 

 long continued, on Inorganic and Organic Substances. By 

 Robert Mallet, M.R.I.A. 



The original object of these experiments has been to try how 

 far it is possible to form many mineral substances which we 

 either have not formed in the laboratory, or which have only 

 hitherto been produced by the dry method. 



Many circumstances concur with the few scattered experi- 

 ments which have been made on this subject in causing us to 

 suppose that this may frequently be effected by the long-con- 

 tinued action of boiling water or steam, or both, on the consti- 

 tuents of the mineral to be formed. 



These may be presented to the action of these agents either 

 in a nascent state, as in silex and earths, or oxides recently pre- 

 cipitated, without being dried and mixed in the atomic propor- 

 tions required to constitute a given mineral if combined ; or 

 the mineral may be formed by the mutual decomposition and 

 recombination of other bodies, more or less difficultly soluble 

 in boiling water. Attention has been directed to both methods, 

 and indications are not wanting to give hopes of success in 

 both. It has been, for instance, some time known, that chal- 

 cedony may be formed by the prolonged action of a boiling 

 temperature upon gelatinized silica ; while, on the other hand, 

 it can be equally well formed by the decomposition of certain 

 kinds of glass by the same means as remarked by the late Dr. 

 Turner. Indeed, the extreme facility with which almost every 

 kind of glass decomposes, under the continued action of boil- 

 ing water, has greatly retarded these experiments. None has 

 been found to answer the purpose but the hard Bohemian 

 glass, (which is objectionable in point of expense,) and green 

 bottle glass ; the latter imperfectly. 



The minerals as yet chosen for experiment have been chiefly 

 hydrates, of which the following may serve as a type ; the 

 production of these has been attempted by direct combination 

 of their constituents with excess of water. 



Formula adopted. 

 Chalcedony or Opal . . . . Sg + H O 



Lenzinite . A + S + HO , 



Triklasite A + S^ + HO 



CymoUte A + Sg + HO 



Terre de Reigate A + S4 + 3HO 



