they improre in hardnees, and the limit or measore of this
oontiuuone induration is the final crystallization of the com-
pacted mass. Accuracy of amalgamation of the materials,
and their jndicioos selection, will, as a matter of ooorse,
iiifliience the ralae of the products, for the machine can only
ensure their true mechanical concretion.
An application of cement cylinders instead of iron fcff
docks, wharf walls, and other similar purposes, has been
executed with the most satisfactory results. Mr. Mflroy,
under the direction of Messrs. Batem^ut and Deas, liaa
constructed brick cylinders, set in Portland cement, at
Glasgow in a new wharf or quay wall of the harbour. The
adoption of ihe brick cylinder in this instance was doe to
the circumstance of bricks being at that time nnnsaally
cheap, but an extension of the wall has been made in
concrete cylinders, as bricks have doubled in price since the
time of the first erection.' Mr. Milroy, in conjunction with
Mr. J. W. Butler, has for a long time advocated this system
of cylindrical or columnar foundations, and the means and
appliances they hare designed for the succesaful execution
of such works are most ingenious and satisfactory in char
racter. Brick cylinders have been used for veils in India
from a very remote period, and indeed in this country
similar applications in a rough and careless manner have
been made for well sinking, more especially in the mnil
districts of England. These works must, however, be re-
garded as very insignificant in comparison with the opera-
tions conducted by Mr. Milroy, whose words we will use
to describe their nature and extent.
