

1818.] Scientific Intelligence. 315 



Palatinate, were kept at a red heat in a platinum crucible with 

 three times their weight of potash ; the porous mass, which was 

 of a greenish brown colour, was well washed with boiling water, 

 so as to separate the soluble matter from the oxide of iron and 

 the earths which are insoluble in potash. The alkaline fluid when 

 filtered was slightly supersaturated by sulphuric acid, in order 

 to convert the earths into sulphates, and to decompose the 

 borate of potash which might have been formed at a red heat. 



The fluid was evaporated to dryness, and the pulverulent resi- 

 duum treated with boiling alcohol, which has no action upon the 

 sulphate or the silex. 



The alcoholic solution when filtered was observed to burn with 

 a green flame. Having been evaporated to dryness, and the 

 residuum heated in a platinum crucible to drive off the free sul- 

 phuric acid, a white substance remained which, when dissolved 

 in boiling water, deposited by cooling scales of a white pearly 

 appearance, which were verifiable by a red heat, and exhibited 

 all the properties of boracic acid . 



M. Vogel also found boracic acid in a specimen of tour- 

 maline brought from Madagascar, which had been formerly 

 given him by M. De la Metherie. 



If we wish to know, by a single operation, whether a mineral 

 contains boracic acid, it is only necessary to boil it for some 

 time in a crucible of platinum with twice its weight of concen- 

 trated sulphuric acid ; the residuum, when nearly dried, is to be 

 washed with warm alcohol, which will burn with a green flame 

 if the substance contains boracic acid. 



Experiments similar to those made with tourmaline have 

 enabled M. Vogel to detect the boracic acid in axinite from 

 Dauphine. 



M. Vogel informs us, that in a late number of Gilbert's Ann. 

 der Phys. there is a letter from Lampadius, in which it is said 

 that tourmaline contains boracic acid; but we have no particulars 

 given on the subject. 



We are informed that M. Arfvedson has procured boracic acid 

 from tourmaline in combination with lithina. 



The readers of the Annals are informed, that for reasons which 

 it is unnecessary to obtrude upon the public, Mr. Aikin and 

 Dr. Bostockfrom this time cease to have any connexion with the 

 work. The last twelve numbers have been entirely edited by them ; 

 and, therefore, whatever responsibility has been incurred during 

 this period falls upon them alone. The Editorship will now be 

 resumed exclusively by Dr. Thomson. 



