A
layer of cast-iron turnings resting on a layer of carborundum grit, the
exhaustion being effected through a hole in the side of the mould
covered by a perforated steel plate within the layer of grit, heat was
applied as usual by a central carbon rod.
Analysis
yielded some thin crystal plates from the grit which had lain in the
line between the cast iron and the suction outlet at the grid, and also
from the layer of grit which had lain against the cast-iron turnings
which had become heated but not melted by the central carbon rod.
To
ascertain the cause of the occurrence of these plates, experiments were
made, without bulk pressure, on the concentrated action of the gases
given off from cast-iron turnings heated up to a good red, and drawn by
a high-vacuum pump through carborundum grit placed in a silica tube
