weight of the blowing-iron is supported upon a rest, and a rotary motion is given to the fingers and disc, by means of a fly-wheel attached to its base. The disc forms the bottom, and the fingers shape the outside of the tumbler by friction.
In Fig. 778, a bc illustrate the process of affixing a handle to a jug. A small quantity of glass is gathered at the end of a working-rod, and is rolled to an even thickness upon the marver. It is now lengthened by holding the rod with the glass downwards, and by pulling the free end with a pair of pincers. When the mass is sufficiently long, the free end is made to adhere to the side of the jug, and the other end is severed from the iron by the shears. The end which now remains free is seized by the pincers, bent round, and made to adhere to another point on the side of the jug, below, but in the same line with, the first junetlon. If it be wished to form a compartment for ice, in the inside of the body of a jug or decanter, the body must he blown in the usual way, and, whilst it is still attached to the blow pipe, a mass of molten glass must be dropped upon one side of it, and suction be applied to the mouth of the blow-pipe ; by this means, the hot glass is drawn inwards, through the wall of the body of the decanter or jug, and the pressure of the external air forms the hot mass into an open bulb.
Fig. 779, abode f, illustrates the formation of long flower-vases. A suf ficient weight of glass is gathered and rolled. An indentation is made in order to form a knob, and the mass is expanded as shown at c. By swinging the bulb with the knob downwards, the bulb becomes greatly elongated.
A working-rod is attached to the knob, and the other end is severed from the blow-pipe. The rough edge is sheared, and the open mouth is formed by rota tion.
The manufacture of tubes and solid canes of glass depends upon the almost unlimited ductility of glass in the intermediate condition between liquidity and solidity. In making cane, a mass of glass is gathered, and rolled upon the marver. A flat disc of glass, adhering to a working-rod, is fixed to the end of the mass opposite to the attachment of the blow-pipe. The workman retains his blow-pipe in his hands, and an assistant holds the working-rod. The workman and assistant now separate, and recede from each other ; the greater the distauee is by which they are separated, the smaller will be the diameter, and the greater the length, of the glass which unites them. Tube is made in the same way as solid cane, with the difference that the mass of glass is
blown into and expanded before it is extended. The stages of tube-drawing are illustrated in Figs. 780, 781 : a is the solid mass of marvered glass ; b c, the same expanded ; d, the working-rod with disc of glass attached; f g, the process of drawing. The shape given to the mass of the glass, or to the hollow within the mass before extension, will be retained by the tube after extension. If the mass be flattened, a flat or oval tube will be formed; if moulded into a triangular form, the tube will be triangular ; if the hollow mass be flattened, and then dipped into the crucible, and fresh glass gathered upon it, a round tube with a flattened bore will be produced. These facts are taken advantage of in making tubes for thermometers. A flattened bore makes the mercury more visible, and an angle in front of the bore magnifies it. Thermometer-tube backed with enamel is thus formed :—A mass of glass is gathered, blown hollow, and flattened by pressure ; upon one side of the flattened mass, a thin cake of hot enamel is carefully spread and fixed ; the mass with the enamel attached is dipped into the crucible, and coated with glass ; it is then marvered, moulded into any form, and finally drawn out in the same manner as ordinary tube.
Fig. 782 represents the process of making variegated cane or tube. A mass of molten glass attached to the blow-pipe is pressed into a circular open mould, around the inside of which, short lengths of coloured cane have been arranged. The mass is withdrawn with the canes adher ing to its surface, and, after being rolled upon the marver to effect amalgamation, is drawn out in the usual manner. If short lengths of variegated cane be used in the above pro cess, in the place of plain coloured cane, the seotion of the cane produced will hear some resemblance to a flower. Pretty effects may be obtained by incorporating minute sections of the " flower " cane in the bodies of decanters, or in the bowls of wine-glasses, and by sur rounding them with engraved foliage.