of the present company to be superfluous. But is this really so? The
author thinks not, and he hopes by the following communication, to
place before this meeting and the community at large some facts which
have up to the present time, or until within a very recent date, been
practically disregarded or overlooked in the production of this very
important and valuable material, so essential in carrying out the
great and important works of the present day, whether of docks and
harbors, our coast defenses, or our more numerous operations on land,
including the construction of our railways, tunnels, and bridges,
aqueducts, viaducts, foundations, etc. The author does not propose to
occupy the time of this meeting by referring to the origin or the
circumstances attendant upon the early history of this material, the
manufacture of which has now assumed such gigantic proportions--these
matters have already been fully dealt with by other more competent
authorities; but rather to direct the attention of those interested
therein to certain modifications, which he considers improvements, by
means of which a large proportion of capital unnecessarily involved in
its manufacture may be set free in the future, the method of
manufacture simplified, the cost of manipulation reduced, and stronger
and more uniformly reliable cement be placed within the reach of those
upon whom devolves the duty and responsibility of constructing works
of a substantial and permanent character; but in order to do this it
will be necessary to allude to certain palpable errors and defects
which, in the author's opinion, are perpetuated, and are in general
practice at the present day.

Portland cement is, as is well known, composed of a mixture of chalk,
or other carbonate of lime, and clay--such as is obtained on the banks
of the Thames or the Medway--intimately mixed and then subjected to
heat in a kiln, producing incipient fusion, and thereby forming a