164 
This Table gives the amounts of arsenic on a practical scale 
so that the total impurity may be seen at once. 
We see by this Table how the arsenic persistently adheres 
to the products in the manufacture of which acid made from 
Pyrites has been used, and how it becomes distributed 
through the acid and soda in various stages. 
The arsenic also has an effect on the Nitric Acid supplied 
to the lead chamber, being converted from arsenious to 
arsenic acid, and thereby causing a slight loss of the Nitric 
Acid Gas. In the deposit in the chamber (mentioned in 
table II.) were found crystals of Arsenic Acid, as a proof 
of this result. 
Mr. Boyd Dawkins, F.R.S., exhibited a collection of 
human bones obtained from a cave at Terlhi Chwareu, a 
place about six miles from Llangollen, and from a cham- 
bered tomb at Cefn, near St. Asaph. The corpses to which 
they belonged had been buried in the sitting posture, as in 
most of the Neolillni interments. The examination of the 
skulls proved that the cranial capacity of the ancient 
dwellers in Denbighshire at that time was not below the 
average at the present day. The angle at which the nasals 
articulated with the frontals showed that their noses were of 
the turned-up order, and in no sense aquiline. Their sta- 
ture, however, ranged from 5 feet to 5 feet 4 or G inches. 
Some of the leg bones from both interments exhibited the 
peculiar antero-posterior flatness of shin which Prof. Busk 
terms platycnemic, and which M. Broca believes to be a 
race-character, while others were of the more usual form. 
The flatness however differed from that observed in the 
interments of France and Gibraltar, in that it was due to 
the anterior extension of the bone, and not to its posterior 
extension. The skulls differ most materially from both 
those of Gibraltar and of France. It follows therefore that 
M. Broca’s estimate of the value of platycnemism as a race- 
character is far too high, since it is found to obtain in skelc- 
