etimes
the composition is cast in large, heavy slabs, moulded on the top to
resemble the surface of roads of granite blocks. A feature of the
invention is the rapidity with which the composition sets. For instance,
the manager states that a roadway was finished at the Inventions
Exhibition at seven o'clock one night, and at six o'clock next morning
four or five tons of paper in vans passed over it into the building,
without doing any harm to the new road. In laying down roads, much of the
preparation of the material is done on the spot, and the composition
after being put down unsilicated in a large layer has the required design
stamped upon its wet surface by means of wooden or gutta-percha moulds.
As regards the durability of the composition, Mr. T. Grover, one of the
directors, says that the company guarantees its paving work for ten
years, and that the paving, the whole of the ornamental tracings, and
some of the other work at Upton Church, Forest Gate, Essex, were executed
by means of Wilkes' metallic cement three years ago, and will now bear
examination as to its resistance to the action of weather. Some of this
paving has been down in Oxford Street, London, for more than six years.
Mr. A.R. Robinson, C.E., London agent of the company, states that the
North Metropolitan Tramway Company has about 25,000 yards of it in use at
the present time, and that the paving is largely used by the War Office
for cavalry stables. The latter is a good test, for paving for stables
must be non-slippery and have good power of resisting chemical action.

In the Wm. Millar and Christian Fair Nichols patent for "Improvements in
the means of accelerating the setting and hardening of cements," they
take advantage of the hydraulicity of certain of the salts of magnesia,
by which the cements set hard and quickly while wet. For accelerating the
setting of cements they use carbonate of soda, alum, and carbonate of
ammonia; for indurating or increasing the hardening properties of cements
they use chloride of calcium, oxide of magnesia, and chloride of magnesia
or bittern water; for obtaining an intense hardness they use oxychloride
of magnesia. The inventors do not bind themselves to any fixed
proportions, but give the following as the best within their knowledge.
For colored concretes for casts or other purposes they use Carbonate of
soda, 8.41; carbonate of ammonia, 1.12; chloride of magnesia, 0.28;
borax, 0.56; water, 89.63; total, 100.00.