Certain limitations to the use of all kinds of plate-glass, whether rough-rolled, figured or polished, were formerly set by the fact that under the influence of fire, partitions of glass were liable to crack, splinter and fall to pieces, thus causing damage beyond their own destruction and leaving a free passage for the propagation of the fire. To overcome these disadvantages, glass manufacturers have been led to introduce a network or meshing of wire into the body of such glass. Provided that the glass and wire can be made so as to unite properly, then the properties of such reinforced or “wired” glass should be extremely valuable. In the event of breakage from any cause, such as fire or a violent blow, while the glass would still crack, the fragments would be held together by the wire network, and the plates of glass as a whole would remain in place, neither causing destruction through flying fragments nor allowing fire or, for the matter of that, burglar a free passage. The utility of such a material has been readily recognised, but the difficulty lies in its production. These difficulties arise from two causes. The most serious of these is the considerable difference between the thermal expansion of the glass and of the wire to be embedded in it. The wire is necessarily introduced into red-hot glass while the latter is being rolled or cast, and therefore glass and wire have to cool down from a red heat together. During this cooling process the wire contracts much more than the glass, and breakage either results immediately, or the glass is left in a condition of severe strain and is liable to crack spontaneously afterwards. An attempt has been made to overcome this difficulty by using wire made of a nickel steel alloy, whose thermal expansion is very similar to that of glass; but, as a matter of fact, this similarity of thermal expansion is only known to hold for a short range of moderate temperatures, and probably does not hold when the steel alloy is heated to redness. In another direction, greater success is to be attained by the use of wire of a very ductile metal which should yield to the stress that comes upon it during cooling; probably copper wire would answer the purpose, but the great cost of copper is a deterrent from its use. A second difficulty is met with in introducing wire netting into glass during the rolling operation, and this lies in effecting a clean join between glass and wire. Most metals when heated give off a considerable quantity of gas, and when this gas is evolved after the wire has been embedded in glass, numerous bubbles are formed, and these not only render the glass very unsightly but also lessen the adhesion between the wire and the glass. This difficulty, however, can be overcome more readily than the first, since the surface of the metal can be kept clean and the gas expelled from the interior of the wire by preliminary heating. On the whole, however, wired glass is perhaps