PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 115 
And this inference is borne out in a marked manner by a consideration of 
the peculiar substance which fills the rents in serpentine rocks; and this con- 
sideration leaves little or no doubt that the so-called steatite or seifenstein from 
Cornwall and from all serpentine rocks must be withdrawn from the species, 
and that the name must, as I have shown above, be in future confined to 
one of the materials which plug the amygdules or rarely the rents of igneous 
vocks. 
The suggestion of DAna’s that as, if we suppose the alumina to be present 
as kaolinite, the rest is a silicate allied to aphrodite,—as if the mineral were a 
minture of the two,—I cannot regard as sound, for the two reasons that, accord- 
ing to Dana himself, neither kaolinite nor aphrodite occur in volcanic rocks 
(nothing of the kind is to be seen in the Scotch ones), and because, as he him- 
self states, kaolinite is not decomposed by acid, while saponite is. 
Any admixture “as kaolinite,” with a mineral soluble in acid, would after 
treatment therewith disclose itself by remaining as an insoluble residue. 
The features, so far as I have yet attained to the recognition of them, 
whereby this super-hydrated vein-serpentine can be discriminated from saponite, 
are the very much smaller amount of its loss of water when heated,—its smailer 
content of water,—and a peculiar opalescence and girasol appearance, which 
it presents, when transparent varieties are looked through. 
In five analyses of these “ vein-serpentines” from Scotland which I have 
executed, I have found the quantity of total water to lie between 15°16 and 
16 ‘58 per cent.; and of this the loss at 212° ranged from 1 * 63, which was that 
of the lowest total, to 3-53, which was that of the highest. 
The deduction of these losses, it will be observed, brings the residual water 
to about the amount normal to serpentine. 
Such were the conclusions I had arrived at when the receipt of a box of 
Trish serpentines from Professor Kine, containing specimens of the “ saponite 
veins ” of Cornwall collected by himself, enabled me by analyses to speak with 
more precision on the matter. 
The specimens of the Cornish “saponite” were at once seen to be physically 
very similar to the paler-coloured vein-serpentines of Portsoy. Being apparently 
somewhat weathered they were opaque, and the girasol appearance could not 
be seen. 
A weathered vein from the serpentine of Polmally, in Glen Urquhart, which 
was very similar, was analysed along with this Cornish saponite. 
It is not necessary here to quote more than the content of water, and loss 
thereof at 212°: this was— 
Total water. Loss at 212°. 
Mineral from Cornwall, .. 5 14°133 1°166 
re »  Polmally, : : 15:162 1° 626 
VOL. XXIx, PART I. Ee 
