Page:Encyclopædia Britannica, Ninth Edition, v. 4.djvu/571

Rh GLAZING.] BUILDING JOS edges will remain unattaclied ; these are readily struck off with a large sable or camel-hair brush, fitted for the pur pose; and the joints, if the work be dexterously executed, will be invisible. This is called oil gilding, and it is by far the best fitted for the enrichment of surfaces in archi tecture, because it is durable, and is easily cleaned, and does not destroy or derange the forms under it so much as burnished gilding does. The latter requires the work to be covered with various laminae of gluten, plaster, and bole, which last is mixed with gold size, to secure the ad hesion of the leaf. GLAZING. The business of the glazier, the manufacture of whose material has of late years improved and progressed in a very remarkable degree, may be confined to the mere fit ting and setting of glass ; even the cutting of the plates up into squares being generally an independent art, requir ing a degree of tact and judgment not necessarily possessed by the building artificer. The glazier is supplied with a diamond or other cutting tool, laths or straight-edges of various lengths, a square, a glazing-knivc, a hacking knife, a hammer, a duster, a sash- tool, a two-foot rule, and a machine called a glazier s horse, which he fixes outside a window sill, and stands on to reach the upper panes for glazing or cleaning purposes, without removing the sash, and so injuring the beads and paint. His materials are simply glass, putty, and priming or paint. The glass is supplied by the glass-cutter, of the quali ties and sizes required for the particular work to be executed. The putty is made by the glazier himself, or by a labourer, of fine clean powdered chalk or whitening, well mixed and combined with linseed oil, and kneaded to the con sistence of dough. No more putty should be made at once than is likely to be worked up in the course of a few days, as, the oil drying out, it becomes hard and partially set, and is therefore less available for its purposes. Priming is a thin solution of white (with a little red) lead, mixed in linseed oil. For ordinary glass, the sashes are sent to the glazier from the joiner, after having been fitted into their places, and only require to be glazed before they are per manently set or hung. Supposing that no preliminary process is required, such as stopping (the result of bad joiners work) and knotting (and knotty stuff should not be admitted in sashes), the sashes require to be primed. The priming is laid on every part of the sash except the outer edges of the styles and of the bottom and top rails, with the sash tool or painting brush, that is, if the sashes are intended to be painted; for if not, the rebates only must be primed. The object of this is to prepare the material of which the sash is composed for the reception of the putty, which would not otherwise attach itself so firmly as it does after this preparation. The priming being sufficiently dry, the workman cuts the panes of glass down into their places, making every one fall readily into the rebates without binding in any part ; indeed the glass should fit so nicely as not to touch the wood with its edges anywhere, and yet hardly allow a fine point to pass be tween it and the sash-bar or rebate, the object being to encase it completely in putty, and yet that the putty should not be in greater quantity than is absolutely necessary. The glass being fitted or cut down, the workman takes the glazing-knife in his right hand, and a lump of putty in the palm of his left, the sash being laid on its face, that is, with the rebates upward, before him ; with the knife he lays a complete bedding of putty on the returning narrow titops of the rebates, all round to every pane. This being done, the panes of glass are put on it as they have been fitted, and every one is carefully rubbed down with the fingers, forcing the putty out below and round the edges of the glass, until they are nearly brought into contact with the wood or other material of the sash. The rebates are then filled in with putty behind, the mass forming exactly a right-angled triangle, its base being the extent of the stop of the rebate, and its perpendicular the depth from the glass to the outer edge of the rebate ; and the third side or hypothenuse is neatly smoothed off. The sash, being then turned on its edge and held upright by the left hand, the protruded putty of the bedding, or back putty as it is called, is struck off with the knife, and the section of it neatly drawn. The sashes are now deposited on their faces to allow the putty to set, and then they may be hung and painted. To very large squares, and to plate glass, needle points, or small nails called sprigs, are used to retain the material securely in its place while the putty is soft and yielding. These have to be carefully inserted, for if they fix the glass it is apt to fly at any sudden vibration. Large squares and plate glass are usually inserted after the sashes are hung, to prevent risks of breakage. Where the bar and frame can be made to allow of it, large squares are secured in their place by wood beads screwed to the rebate in lieu of putty. In this case the edge of the glass is first covered with a piece of flannel, or thin india-rubber, to fill up crevices, and so prevent admission of dust, and stop any current of air. Lead-work, as it is termed, is the glazing of frames Lead-work, rather than of sashes with small squares or quarries of glass, which are held together by reticulations of lead ; and these are secured to stout metal bars, which are fixed to the window frames. Leaden reticulating bars are grooved on their edges to receive the quarries, and are tied by means of leaden ribands or wires to the saddle bars, which, in their turn, are affixed to the stouter bars before men tioned, if the bay or frame be so large as to require both. This is now extensively carried on in the painted glass window shops, where the glass is cut to patterns, and shows outlines of figures, costumes, ifec. &quot; Stained glass &quot; is obtained by mixing colours in the pot while in the furnace, hence the term &quot; pot metal&quot; for it. A kind of coloured glass has only a skin of colour on one side of the white material, and hence is termed &quot; flashed glass.&quot; Besides all the varieties of clear glass, the glazier has Varieties of now at his command the many qualities of obscured glass, glass, beyond the ground and painted glass of former days ; the lace -pattern glass, executed by laying a pattern on the material which &quot;has been covered with a varnish, placing it in a box filled with a fine powder, which when shaken adheres to the varnished portions, and then put ting it in a kiln where it becomes fixed ; the patent rough plate for conservatories, workshops, &c., and its fluted varieties ; the rough cast plate for workshops and store houses ; the stained ornamented quarry for church windows, &c. Lastly, there is the engraving on glass by aid of the sand blast, a new and easily managed method, con sisting in a jet of air blown violently through a tube, carrying with it particles of fine sand. The action is very rapid, and it reduces the surface in a few minutes to the condition of ground glass. A piece of lace, however, is sufficient to arrest the action of the sand. Ileece s patent embossed and coloured glass is useful for screens and for windows which are not meant to be looked through. Coming within the scope of the glazier s business is the novel pavement light, consisting of a frame of iron cast with small many-sided apertures, into which are placed a series of dome-shaped or prism-shaped blocks of glass, reflecting the light falling upon them. They dis tribute the light to a greater extent than a piece of rough plate-glass, and like Chappuis s and other reflectors require to be kept clean. Moore s window ventilator allows of the