1822.] the Sources of the Rivers Ganges and Jumna.” lit 
had so severe a winter asthe last. At Jumnotri, the inclination 
of the granite rock is from 43° to 45° from the horizon; the 
apex being to the SW. or towards the plains. 
As the season was not sufficiently advanced to allow of my 
passing to the Ganges by the Chia or Cilsaum mountains, both 
of which are at present impassable from the depth of snow on 
them, I returned to Catnaur, and going up the Shialba glen, 
crossed the ridge, which divides the two rivers at the Jackent 
Ghat, and descended by Bauna to Barahat, from whence I pro- 
ceeded up the Ganges to Reital, and continued my route beyond 
Gangotri, as before mentioned. 
I shortly hope to be able to present to the Society the resul€ 
of my trigonometrical operations to determine the heights and 
positions of all the peaks of the Himalaya visible from Seharan-. 
pur, and also an account of the sources of the Tonse and 
Jahnavi rivers, and of the upper part of the course of the Setlej. 
ARTICLE III. 
Ona New Lead Ore. By H.1. Brooke, Esq. FRS. & FLS. 
(To the Editor of the Annals of Philosophy.) 
SIR, July 6, 1822. 
Tue third volume of the Edinburgh Philosophical Journal 
contains a notice from me of three varieties of lead ore which 
had not been before accurately described. I have now to add 
a fourth, of which only a very slight account has been given by 
Mr. Sowerby in the third volume of his Brit. Min. p. 5, under 
the name of blue carbonate of copper. 
It is only within a few days that I have had an opportunity of 
examining this substance. 
The specimens I have seen, as well as that figured by Mr. 
Sowerby, were found at Wanloch Head or Lead Hills. 
The facility with which this species may be cleaved, the bril- 
liancy of the cleavage planes, and the angle at which those 
planes incline to each other were indications that the substance 
was not carbonate of copper; and it appears on examination to 
be a compound of sulphate of lead and hydrate of copper, and 
may be denominated cupreous sulphate of lead. 
The colour resembles the brightest specimens of blue carbon- 
ate of copper. 
Specific gravity about 5:3, but as the specimens I possess are 
‘not perfectly free from included particles of carbonate of lead 
and of cupreous sulphato-carbonate of lead, it is probable that 
the specitic gravity of more perfect specimens may differ ina 
