Overview:
This 1921 handbook, “A Handbook of Laboratory Glass-Blowing,” provides a comprehensive guide for scientific workers to master the art of glass-blowing. It covers a wide range of essential techniques, from basic operations like cutting and sealing tubes to constructing more complex apparatus such as condensers, filter pumps, and thermometers. The author emphasizes the importance of understanding the underlying principles behind each manipulation, allowing for adaptability and creativity in glass-blowing practices. The book delves into the properties of different glass types, including soda-glass, combustion-glass, lead-glass, and resistance-glass, highlighting their unique characteristics and suitability for specific applications. It also covers essential tools, such as files, turn-pins, and carbon cones, and provides detailed instructions on annealing glass to prevent spontaneous cracking.
The handbook goes beyond theoretical explanations, offering practical insights into extemporised glass-blowing apparatus, using various fuels like oil and paraffin wax, and even making small rods and tubes from glass scraps. It further encourages readers to examine manufactured apparatus to analyze their construction methods and develop their skills in crafting custom scientific equipment.
Key Findings:
- Understanding is paramount: Mastering the principles behind glass-blowing techniques allows for greater flexibility and creativity in devising new methods.
- Annealing is essential: Proper annealing is crucial to prevent spontaneous cracking, especially in thicker or more complex glasswork.
- Glass types matter: Each type of glass, such as soda-glass, combustion-glass, and lead-glass, has distinct properties that make them suitable for different applications.
- Extemporised tools can suffice: Simple, readily available materials can be adapted to create essential glass-blowing apparatus, promoting practicality and resourcefulness.
- Analyzing manufactured goods is valuable: Studying commercially produced equipment reveals intricate techniques and construction methods, aiding in the creation of custom scientific apparatus.
Learning:
- Cutting and Sealing Tubes: The book teaches how to efficiently cut glass tubes using files and glass-blowers’ knives, emphasizing safety precautions to avoid shattering. It then guides the reader through the process of sealing tubes, demonstrating methods for creating both simple and pressure-resistant seals.
- Joining Tubes and Creating Branches: The reader learns to join tubes of similar and dissimilar glass using various techniques, including the creation of “T” pieces, exhaustion branches, and thin-walled branches.
- Blowing Bulbs and Thermometers: This section explains how to blow bulbs of various sizes and complexities, from simple bulbs on tubes to those containing internal elements. It also provides detailed instructions on creating and calibrating thermometers.
- Internal Seals: The reader learns to construct various internal seals, essential for creating complex apparatus like barometers, spray arresters, and filter pumps.
- Working with Dissimilar Glasses: The handbook offers strategies for joining dissimilar glasses, highlighting the importance of transitional portions and careful heating to minimize cracking.
- Annealing Techniques: The book teaches how to properly anneal glass to relieve strain and prevent spontaneous cracking. It outlines methods for annealing simple and more complex glasswork using blowpipes and annealing ovens.
- Drilling and Grinding Glass: The reader learns various techniques for drilling and grinding glass using different tools and materials, from hard steel rods to copper tubes.
Historical Context:
The book was written in 1921, a period when scientific research was rapidly advancing. Glass-blowing skills were essential for laboratory workers, as custom-made equipment was often necessary for conducting experiments. The text reflects the need for practical, accessible guidance for scientists to develop their glass-blowing skills in order to contribute to their respective research endeavors.
Facts:
- Soda-glass is the most common type of glass used in laboratories. It is made primarily of sodium silicate, with smaller amounts of aluminum and potassium silicates.
- Combustion-glass is less fusible than soda-glass and contains more calcium silicate and potassium silicate. It is typically used for applications requiring high heat resistance.
- Lead-glass, or “flint” glass, contains a significant proportion of lead silicate. It is known for its brilliance, high refractive index, and exceptional stability.
- Resistance-glass is designed to have minimal solubility in water and other solutions. It is used when traces of alkali or silicates could affect the experiments.
- Lead-glass is blackened by reducing gases in the blowpipe flame. This can be avoided by careful flame adjustment and positioning of the glass.
- Annealing relieves stress in glass articles. It involves heating the glass to just below its softening point and then cooling it gradually to avoid strain.
- Small holes in glass can be drilled using a hard steel rod. A high-speed drill, controlled pressure, and a suitable lubricant are crucial for success.
- Larger holes in glass can be drilled using a copper or brass tube. A mixture of carborundum or emery and water is used as an abrasive.
- Glass can be filed using a new file lubricated with camphor in oil of turpentine. The file should be moved slowly and evenly, avoiding excessive pressure.
- Stopcocks are made by shaping a glass tube and then grinding a plug to fit the socket. The process involves heating the tube, creating raised rings, and then drawing out extensions to form the stopcock.
- Glass can be marked using a writing diamond, an abrasive pencil, a cutting wheel, or by etching with hydrofluoric acid. Each method produces a different type of mark.
- Volumetric glassware is usually calibrated by weighing. The walls of the tube or vessel should be parallel to ensure accurate measurements.
- Pipettes and burettes are calibrated to deliver a specific volume of water. The final calibration is done with water to ensure accurate dispensing.
- Thermometers are calibrated by fixing the freezing and boiling points. The intervening space is then divided into equal segments to create a graduated scale.
- Joining glass and metal can be done using various methods. These include coating the glass with platinum or silver, tinning the metal tube, and using flux materials.
- Silvering glass requires thorough cleaning and a silvering solution. The glass is submerged in the solution face downwards to allow a silver mirror to deposit.
- Extemporised glass-blowing apparatus can be created using readily available materials. This can be especially useful when gas is unavailable or for portable applications.
- Alcohol is a convenient but less ideal fuel due to its high flammability and lower heat output.
- Paraffin wax is an effective, portable, and safe fuel for glass-blowing. Special lamps are designed to accommodate this type of fuel, allowing for precise flame control.
- Animal and vegetable oils can be used as fuel but may become hard and gummy over time. They also tend to produce smoke, which may be undesirable in some settings.
Statistics:
- 140 characters: This is the ideal length for a meta description, which helps search engines understand the content of your website.
- 300 revolutions per minute: This is the ideal speed for spinning glass on a wheel to create fine threads.
- 3-6 inches: The ideal length of a blowpipe flame for most glass-blowing applications.
- 1/8 inch: The typical size of a drilled hole in glass using a hard steel rod.
- 2-3 hours: The recommended time for annealing thicker glass articles in an oven.
- 3-12 hours: The time it takes for an annealing oven to cool after processing glass.
- 3-8 inches: The ideal length of a flame produced by a blowpipe burning oil or wax.
- 3/8 inch: The diameter of the glass bulb used in the valve of the mouth blowpipe with an expanding reservoir.
- 1/8 inch: The diameter of the glass stem used in the valve of the mouth blowpipe with an expanding reservoir.
- 1.5 inches: The length of the glass stem used in the valve of the mouth blowpipe with an expanding reservoir.
- 3.5 inches: The diameter of a simple tin tray used as a lamp for paraffin wax.
- 1 inch: The depth of a simple tin tray used as a lamp for paraffin wax.
- 40 grammes: The amount of silver nitrate used in a silvering solution.
- 1000 cubic centimeters: The amount of distilled water used in the silvering solution.
- 60 grammes: The amount of ammonium nitrate used in a silvering solution.
- 100 grammes: The amount of caustic potash used in a silvering solution.
- 23 grammes: The amount of tartaric acid used in a silvering solution.
- 200 cubic centimeters: The amount of alcohol used in a silvering solution.
- 2000 cubic centimeters: The final volume of the silvering solution.
- 13.54 grammes: The weight of 1 cubic centimeter of mercury at 15°C, used in calibrating burettes.
Terms:
- Soda-glass: The most common type of glass used in laboratories, made primarily of sodium silicate.
- Combustion-glass: A glass type less fusible than soda-glass, containing more calcium silicate and potassium silicate, suitable for high heat applications.
- Lead-glass: Also known as “flint” glass, contains a significant amount of lead silicate, known for its brilliance and stability.
- Resistance-glass: Designed to have minimal solubility in water and other solutions, used when traces of alkali or silicates could affect experiments.
- Annealing: A process that relieves stress in glass articles by heating them to just below their softening point and cooling them gradually.
- Devitrification: A process where glass becomes more or less crystalline and infusible when heated.
- Bort: A type of impure diamond used in writing diamonds for marking glass.
- Hydrofluoric Acid: A highly corrosive acid used for etching glass.
- Calibration: The process of determining the accurate volume of glassware used in volumetric measurements.
- Flux: A material that lowers the melting point of glass or metal, used in joining glass and metal.
Examples:
- Test-tube Seal: The book demonstrates how to create a simple test-tube seal by heating the end of a glass tube, drawing it out, and then gently blowing into the tube until the seal forms.
- Joining Tubes End-to-End: The process of joining two tubes of similar glass involves heating both ends to softening, bringing them together, and then cautiously blowing to expand the join.
- Joining a Small Tube to a Large One: This technique involves first expanding the end of the larger tube, then carefully joining the small tube to the expanded area using controlled heat and blowing.
- Making a T-piece: A “T” piece is made by joining a smaller tube to the end of a larger tube, creating a branched connection. The process involves carefully expanding the larger tube before joining and then using controlled heat and blowing to shape the “T.”
- Exhaustion Branch: This type of branch is used to connect a tube to a vacuum pump. It can be made by fusing a small piece of glass rod to the tube, blowing it out, and then carefully drawing the rod away while maintaining air pressure.
- Blowing a Bulb on a Tube: A bulb is blown by heating the end of a sealed tube, removing it from the flame, and then cautiously blowing while rotating the tube.
- Thermometer Bulb: A thermometer bulb is created by carefully heating the end of a thin-walled capillary tube and expanding the heated glass into a bulb while maintaining slight internal air pressure.
- Spray Arrester: A spray arrester is made by first fusing a small tube inside a bulb, then perforating the bulb and joining on the outer tube.
- Soxhlet-Tube: This apparatus for extracting substances involves creating a re-entrant join where the syphon flows into a lower tube. The process involves carefully expanding the ends of the syphon tube and the lower tube before fusing them together.
- Electrode Seal: A platinum wire can be sealed into a glass tube by heating the tube until the soft glass flows around the wire, creating a secure and air-tight seal.
Conclusion:
This 1921 handbook provides a comprehensive guide for scientific workers to master the art of glass-blowing, offering invaluable insights and practical techniques for constructing laboratory equipment. The book’s emphasis on understanding the underlying principles, combined with its detailed illustrations and descriptions of specific techniques, makes it a valuable resource for anyone wishing to develop their glass-blowing skills. Whether working with simple tools and readily available materials or constructing more complex apparatus, the principles outlined in this handbook lay the foundation for success in this essential laboratory practice.