126 
Dr Turner on the Detection of 
by such means. To try if its presence could be discovered by 
other methods, I had recourse to the fluxes that have been re- 
commended for lithia. The bifluate of potash, and the mixture 
of sulphate of ammonia and fluate of lime, gave no indication of 
boracic acid; but I succeeded completely with the flux which is 
composed of one part of fluate of lime and four and a half of the 
bisulphate of potash. About equal parts of this flux and pow- 
dered tourmaline are mixed together on the palm of the hand, 
being at the same time formed into a paste by a little moisture. 
A small particle of the mixture is then taken up on platinum- 
wire, and exposed to the blowpipe-flame, not at its apex, but 
somewhat nearer the wick than the point of the blue flame. 
Fusion takes place, and at the moment it does so, the portion of 
the flame beyond the assay is tinged of a pure green colour. 
This effect is most distinct and unequivocal, but the opera- 
tion requires some care. The green colour appears only for an 
instant, at the very commencement of fusion ; and having once 
ceased, it cannot be made to appear again, however long the 
blast may be continued. 
Through the kindness of my friends, Mr Allan and Mr Gre- 
gory, I have been supplied with a considerable variety of speci- 
mens of tourmaline and schorl, and all of them, without excep- 
tion, give indications of boracic acid. The following is a list of 
those that have been examined : 
Dark-blue Tourmaline, 
Green T. 
Black T. 
Black T. 
Black T. 
Black T. 
Brownish-black T. 
Black T, 
Black T. 
Liver-brown T. 
Liver-brown, fibrous and 
Black T. 
Black T. 
Black T. 
Black T. » « 
Black T. 
diverging, 
from Massachusetts. 
Do. 
Brazils. 
Abo, in Finland. 
Finbo ? 
Arendal, in Norway. 
Karingsbrycka, Sweden. 
St Gotthard. 
Cornwall. 
Do. 
Do. 
Ross-shire. 
Banffshire. 
Aberdeenshire. 
Germany. 
Penig, in Saxony. 
From the occurrence of boracic acid in all these varieties, 
