USES OF CEMENT.

Probably few materials have been found more generally useful to

the civil engineer, in works which are not of metal, than has been

Portland cement. It should be noticed that during the last twenty-two

years great improvements have been made in the grinding and in the

quality of the cement. These have been largely due to the labors

in England of our member, Mr. John Grant, to the labors of foreign

engineers following in his footsteps, and to the zeal and intelligence

with which the manufacturers have followed up the question, from a

scientific as well as from a practical point of view, not resting

until they were able with certainty to produce a cement such as the

engineer needed. I do not know that there is very much to be said in

the way of progress (so far as the finished results are concerned) in

the materials which Portland cement and other mortars are intended to

unite. Clean gravel and ballast and clean sand are, I presume, very

much the same in the year 1884 as they were not only in the year 1862,

but as they were in the year 1. The same remark applies to stone

and to all other natural building materials; and, indeed, even the

artificial material brick cannot in these days be said to surpass in

quality the bricks used by the Romans in this island nineteen hundred

years ago, but as regards the mode of manufacture and the materials

employed there is progress to be noted. The brick-making machine and

the Hoffmann kiln have economized labor and fuel, while attempts have

been made, which I trust may prove successful, for utilizing the clay

which is to be found in the form of slate in those enormous mounds

of waste which disfigure the landscape in the neighborhood of slate

quarries. Certain artificial stones, moreover, appear at last to be

made with a uniformity and a power of endurance, and in respect of

these qualities compare favorably with the best natural stone, and

still more favorably having regard to the fact that they can be made

of the desired dimensions and shape, thus being ready for use without

labor of preparation.

Scientific American Supplement, No. 488, May 9, 1885 · 第 27 / 59 题