TRANSACTIONS OF THE SECTIONS. 
Examination of the Sulphuretted Sulphate of Lead from Drf- 
ton. By James F. W. Johnston, A.M. 
This mineral,—mentioned in Phillips’s System of Mineralogy 
under the name of Supersulphuretted Lead,—is of various 
colours from an almost pure white to a deep lead grey. It 
varies also in hardness, being sometimes so soft as to be easily 
scratched by the nail; at others, offering considerable resist¬ 
ance to the knife. It occurs only massive, often composed of 
distinct layers of different shades of colour, and imbedding occa¬ 
sional crystals of common galena. Mr. Johnston has met with 
one specimen which in the cavities contained minute crystals of 
sulphate of lead. The specific gravity of a dark lead grey va¬ 
riety was 5*275. 
In the flame of a candle it takes fire and burns with a blue 
flame and smell of sulphur. Heated in a close tube, it gives off 
sulphur in large quantity. Oil of turpentine and boiling alcohol 
dissolve sulphur from the mineral when in the state of fine 
powder. The sulphur present, therefore, is not in a state of 
combination with the lead. 
By heating to redness in the open air, a lead grey variety 
lost 10 per cent., a white variety only 7 per cent, of its weight. 
Treated with muriatic acid in a gentle heat, it was decom¬ 
posed and dissolved, with the exception of the sulphur. A lead 
grey specimen left of sulphur 8*71 per cent.; and when the lead 
was separated by sulphuretted hydrogen, the filtered solution 
gave with chloride of barium 69*8 of sulphate of barytes, equi¬ 
valent to 90*38 of sulphate of lead. The mineral therefore 
consists of 
Sulphur ..... 8*71 
Sulphate of lead... 90*38 
99*09 
and is merely a mixture of sulphur with sulphate of lead. 
It occurs at Dufton in the midst of the regular veins : it is 
difficult, without a knowledge of the localities, to understand 
the source of the uncombined sulphur. 
Lecture on a new Safety Tube adapted to the Oxhydrogen 
Blowpipe . By John Hemmings. 
Mr. Hemmings commenced with a few general remarks on 
the advantage to the chemist of the intense and continuous 
heat of the oxhydrogen blowpipe, if it could be employed with- 
