But as a rule engraving is a surface operation, done with a diamond or on the wheel, or by sandblast, or by use of acids. Where the engraving is flat, not cut in, the original greyish-white effect may long remain; a collector need not suppose that the engraving is recent because the tint of it is not brownish, a colour due to years and accumulations of dust. Indeed, the rougher and coarser the recent engraving the more likely dust to settle in it, as well as upon it, and to give it a dusty tint. Really fine old engraving can remain almost as fresh in appearance and tint as it ever was, even till to-day. And the natural tint of glass engraving resembles the tint of ground glass. Of course, when the polishing-wheel was applied, either to parts or to the whole of the engraving, this greyish-white tint was polished away.
The polishing-wheel was also used to remove the pontil-mark (when it was a lump or knob) from the feet of wine and other glasses.
Dutch or German engraved old glass shows more smeary in the engraved part than English or Irish glassware does.
V. OLD COLOURED GLASS
At Bristol, Nailsea, Wrockwardine, and perhaps at Norwich, glassware of various colours was made. There are collectors who care for nothing else but coloured glass; there are collectors who only care for coloured glass paper-weights; there are collectors who will not buy coloured glass at all.
“BRISTOL”
Bristol coloured glass is the most sought for. There are several varieties. The rarest is the opaque, whitish glass which rather resembles porcelain or Battersea enamel in general tint, and is painted upon as if it were porcelain or enamel: held to a good light this ware is seen to be rather opalescent, and might be dubbed opal glass. Edkins, a painter of Bristol delft, used delft-like colours and designs on this opal glass; wreaths of flowers (the rose and the fuchsia in particular) and flourishes in the Louis XV style are characteristic. Cups and saucers, teapots, tumblers, bowls and jugs, cruet vessels, and candlesticks of this ware exist, though few; the last-named imitated Battersea enamel candlesticks in shape and decoration. A characteristic of this glass is ridges or waves on the surface, detected by the finger. The earliest examples have domed and folded feet.