res and a half in height, by four metres and
eleven centimetres in width, which gave it a surface area of 26 metres
12 centimetres. Naturally M. Henrivaux determined to surpass this
prodigy in 1889, and to match the Eiffel Tower with a mirror. The
Belgian rivals of St.-Gobain suspected this, it seems, and sent forth
subtle persons to spy out the plans of the great French manufactory.
These colossal plates of glass are cast upon immense 'tables' of metal,
and by ascertaining the dimensions of the tables ordered for St.-Gobain
the ingenious Belgians hoped to get the measure of the effort it would
be necessary for them to outdo. In anticipation of this subtlety the
director of St.-Gobain ordered two immense tables, and when these were
sent to the manufactory, had them skilfully thrown into one. Upon the
gigantic table thus prepared the grand mirror of the Exposition of 1889
was cast at the eleventh hour. This mirror was the special delight of
the Shah of Persia during his visit of this year to Paris; and as I
suppose the seven plate-glass manufactories which have grown up in my
own beloved country under the benediction of the Protective Tariff,
since a prohibitive duty was originally clapped on plate glass to
encourage the one solitary establishment of the sort then existing in
America, will give themselves up to producing something more stupendous
still for the New York Exposition of 1892, I here set down its
dimensions. It measures in height 7 metres 63 centimetres, and in width
4 metres 10 centimetres, giving it a superficial area of 34 metres 24
centimetres. It is 12 millimetres thick, and weighs 940 kilogrammes.
This enormous glass was cast from a single crucible, containing 1,600
kilogrammes of vitreous matter. To have seen this operation would have
been worth a very much longer journey than that from New York to
St.-Gobain, for the colour and glow of such a mass of vitreous matter in
fusion can only be matched by the evanescent hues of a crimson aurora on
a fine night in the North, or by the intense lights which play over the
surface of a stream of molten lava.

At every stage in the operation the utmost skill and delicacy of
handling are required to convert what might easily pass for a heap of
rubbish swept together from a macadamised roadway into the smooth,
glittering, lustrous plate which the French so picturesquely call a
_glace_, and which indeed most nearly resembles the evenly frozen
surface of a crystal lak