Rubber Blowing Tube.—In complicated work it is often convenient to use a thin rubber blowing-tube which is connected with the work either by a cork and piece of glass tubing or by fitting over a drawn-out end. The use of such a blowing-tube avoids the inconvenience of raising the work to the mouth when internal air-pressure is required. One end of the rubber tube is retained in the mouth during work.
General Notes.—A large amount of glass-blowing is spoiled through carelessness in arranging the work beforehand. The student should have every detail of his manipulation clearly in mind before he commences the work; he should not trust to evolving the method during the actual manipulation.
Undue haste is another fruitful source of failure. Practically every operation in glass-blowing can be carried out in a perfectly leisurely manner, and it is better to err rather on the side of deliberation than on the side of haste.
If, as will doubtless happen at times, a piece of work gives trouble and it is necessary to pause and consider the whole question, or if for any other reason it is necessary to stop during the construction of a partially finished join or other operation, great care should be taken not to allow the work to cool. A large, brush-like flame may be produced by increasing the amount of gas admitted to the blowpipe, and the work should be held just in front of the current of hot air produced by such a flame.
It will then be possible to continue work on this without causing it to crack when further heat is applied.
As time goes on, the student will find an increasing confidence in his ability to manipulate the soft glass, and with increasing confidence will come rapidly increasing power of manipulation. Perhaps the greatest obstacle to success in glass-blowing is undue haste in manipulation.
INDEX
Absorption bulbs, [21], [23].
Airtube, flexible, [8], [102].
Alarm thermometer, [45].
Annealing, [7], [60].
Bellows, adjusting pressure of, [5], [6].
Bellows, foot, [5], [6].
Bending tubes, [23].
Blackening, [58], [101].
Branching, [18], [19].
Brushes of spun glass, [53].
Blowpipe flame, quality of, [3].
Blowpipe for mouth blast, [80], [82], [84].
Blowpipe, for paraffin wax, [82], [88].
Blowpipe, Herepath's, [2].
Blowpipe jet, centring, [3], [98].
Blowpipe jet, dirt in, [3].
Blowpipe jet, multiple, [4], [40].
Blowpipe, Letcher's, change, [4].
Blowpipe, simple form of, [80].
Bulb, medially on tube, [22].
Bulbs, [19], [20], [22], [38], [98].
Bulbs, absorption, (Liebig's), [21], [23].
Bulbs, dividing, [39], [95].
Bulbs from rod, [25].
Bulbs, internal, [38].
Bulbs, thick, [21].
Cages, from glass rod, [24], [25], [27].
Calibration, [72].
Carius tubes, [16].
Condenser, Liebig's, [37].
Condensers, various, [37], [38].
Cone, carbon, [8].
Crack, leading, [30], [99].
Cracking, subversive, [103].
Cutting glass with diamond, [30].
Cutting tubes, [11], [99].
Diamond (glazier's), use of, [30].
Dissimilar glass, joining of, [22], [94].
Drilling, [61].
Electrodes, sealing in, [42], [97].
Etching glass, [70].
Extemporised appliances, [80].
Examination of apparatus, [93].
Failure, Haste chief Source of, [103].
Failures, Notes as to, [97].
File, with oblique ground edge, [7].
Filing glass, [63].
Filter pumps, [35]
Foot, [25]
Fuels various, [82], [86], [87], [89].
Funnel, thistle, [23].
General principles and precautions, [1], [97]
Glass, varieties of, [9], [55], [91]-97.
Graduation, [72]-76
Haste, Source of Failure, [103]
Heat reflector, asbestos, [7].
Heating, intensive, [7], [57].
Heating precautions, [12], [98]
Joining dissimilar glass, [22].
Joining glass to metal, [76].
Joining tubes, [16], [94], [100].
Knife, Glass blower's, [7], [99].
Lenses, grinding, [63].
Marking glass, [69].
Methods, analytic study of, [91], [93].
Oxygen for intensive heating, [57], [101].
Precautions and General Principles, [1], [97].
Pumps, Filter, [35].
Pumps, Sprengel, [49], [50].
Re-entering branch, [40].
Reflector of heat, asbestos, [7].
Rod, uses and articles from, [17], [25], [27], [28].
Rod, blowing to hollow, [17], [25], [26], [91].
Scrap glass, working, [90].
Sealing tubes, [12], [13], [14].
Sealed tubes for pressure, [15], [16].
Sealing in of Electrodes, [42], [97].
Seals, internal (airtraps), [32], [102].
Silvering glass, [77].
Soldering glass, [76].
Soxhlet-tube, [40].
Spirals, [23], [95].
Spray arrester, [34].
Spray producers, [36].
Sprengel pumps, [49], [50].
Spinning glass, [51].
Stopcocks, [60], [66].
Stoppering, [63].
Stirrers, [28], [29].
Summary as to precautions and failures, [97].
Taps, [60], [66].
Thermometers, Various, [44]-49.
Thermo-regulator, [24].
Thistle Funnel, [23].
Tools, Various small, [7].
Turn-pins, [7], [8], [99].
Turning out open ends, [14], [99].