Blair Collection > Place names in Strathbogie, with notes historical, antiquarian and descriptive

40 Place Names in StratJibogie.
of his analyses. Mr. Proctor explains that he
has not estimated the amount of iron and some
of the other constituents, under the different
forms in which they occur in the various speci-
mens ; and that he has not estimated separately
the percentage of those constituents occurring in
very small quantities. For the purpose in view
the analyses are amply sufficient, and prove
conclusively that the fused and unfused stones
of the forts, and the rocks of the hills are
identical. How it could ever have been supposed
that they were different, or that the rocks of the
district were incapable of vitrifaction, I cannot
imagine. There is no difficulty, either on these
forts, or on any other vitrified fort I have visited,
in picking up specimens of the material, partly
fused and partly unfused, the stones being vitri-
fied on one side, and unaffected by fire on the
other.
In order to test the stones in a practical way,
I had specimens of the material of the fort of
Tap o' Noth, and of the rocks in place, put into
the furnace of a brick-kiln, and at a red heat
they were completely fused in fifteen minutes.
I also succeeded in vitrifying fragments of the
rock in a small greenhouse stove, using wood
and peat as fuel ; but my experiment failed with
coke, and 1 found that a white heat merely burnt
the stones, but did not fuse them. The extent
of fusion, of which the rock is capable, appears