PROGRESS IN SPECIAL RESEARCHES. 315 



basalt, serpentine, greenstone, mica, and many other minerals 

 discovered by Mr. Knox [Phil. Jour.), and of fire damp in the 

 vesicles of sal gem by Dumas ; all these indicate the compa- 

 rative low temperature at which the formation of many mine- 

 rals has probably proceeded. 



Coal too has been found in Scotland converted into plumbago 

 by the proximity of a dyke, yet at such a distance that its com- 

 municated heat must have been extremely low. On the other 

 hand, facts are not wanting to indicate the powerful effects of 

 water and a moderate heat in decomposing and changing or- 

 ganic or organized bodies, as, for instance, the changes re- 

 marked by Perkins in the oil of his high-pi'essure steam engine, 

 and very many similar known to the organic chemist. 



Again the analytical chemist is familiar with abundant cases 

 of the direct combination under favourable circumstances — of 

 oxides with oxides, earths with earths, salts with salts, &c., to 

 prove the likelihood of minerals being formed by synthesis 

 ■without further decomposition resulting, than loss of consti- 

 tutional water; as the combination of alumina and magnesia 

 when precipitated together, giving a compound when ignited 

 of A^g + M^, or colourless spinell, as remarked by Chenevix. 



These scattered facts are sufficient to show that the experi- 

 ments here indicated, while they belong to chemistry and mi- 

 neralogy, abound in interest to the geologist. The experiments 

 have not been sufficiently long in operation to yield definite re- 

 sults. 



Provisional Reports and Notices of Progress in Special Re- 

 searches, entrusted to Committees and Individuals. 



Physical Section. 



Professor Forbes contributed a notice of the experiments he 

 has been some time prosecuting into the Temperature of the 

 Earth at different depths, and in different sorts of rock. The 

 results will be laid before a future meeting of the Association. 



Sir J. Robison and Mr. J. S. Russell reported the progress 

 of their investigations on Waves. As this subject has been 

 again entrusted to the further examination of the Committee, 

 it is thought proper to defer the publication of the results already 

 obtained till the Committee shall present their complete report. 



Mr. Baily reported that the Committee appointed to repre- 

 sent to government the importance of reducing the Greenwich 

 observations of the moon, had vraited on the Chancellor of the 

 Exchequer, and that the sum of 2000/. had been appropriated 



