1238 SCIENTIFIC NEWS.' 



which con- The sulphuric acid contained a quantity $f sulphate of 



STilvT P * * J * me > wll ich was deposited on diluting the acid, and which 

 presented crystals precisely similar to those in, the paper 

 alluded to. 



Though being deceived by the impurity of the sulphuric 

 acid does not affect the general conclusions r.s to the acid 

 products obtained by treating ginger root with nitric acid, 

 yet it shows the crystallized matter in the experiments did 

 Kecessarv to not ar ' se ^ rom us * u g white lead, although it was adulterated 

 examine the with chalk, but from using impure sulphuric acid; and 

 pu "* y rea * shows too the necessity of young experimentalists paying- 

 particular attention to the purity of the reagents employed, 

 t I am, Sir, yours very respectfully, 

 Bawtry, June 13, 1810. T. L. G. BREWERTON. 



SCIENTIFIC NEWS, 

 Wemerian Natural History Society, 



Mineralogy of Jr^JT the meeting of this Society on the 7th of April, D»v 

 ■ »g>lands, Mcknight rea d a mineralogical notice, on the tract of the 

 Highlands from Killin to Braemar, by the way of Glen Zilt. 

 Ben Lawers is composed of undulated mica-slate, which at 

 the summit is yellowish-gray, and in some varieties so full 

 of quartz as to resemble a sandstone. Towards Lagierait, 

 beautiful garnets begin to appear. Beyond Mullevearn, 

 gneiss occurs; also limestone, hornblende-slate, and sienite. 

 Besides the substances first mentioned, Glen Zilt is remark-* 

 able by a peculiar aggregate of feldspar, hornblende, and- 

 occasionally quartz; in which the various proportions of 

 these ingredients exhibit the rock under various aspects of 

 the sienitic and greenstone species. It is distinguished from* 

 granite (for which it has been mistaken) not only by the 

 uncrystallized state of the feldspar, but by the presence of 

 hornblende, and the absence of mica. Professor Jameson 

 has called it sienitic greenstone. It occurs in conformable^ 

 beds; particularly one of great size, which intersects the 

 channel of the river at different places, near the lodge. 

 Crossing the mountains from Glen Zilt to the course of the 

 Dee, we find hornstone, feldspar-porphyry, and limestone, 

 subordinate to mica-slate and gneiss; till we reach the Cas- 

 tletown of Braernar, where the granite of the Grampians at 

 length appears. | . r » At 



