1. Alessandro Volta   Laboratory Gas Burner   Refrigerator   Electric Battery   Stethoscope   Hint Half-n-half Clue   2. Dr. Wallace H. Carothers   Hovercraft   Rabies Vaccine   Nylon   Air Pump   Half-n-half Clue   3. Lewis E. Waterman   Fountain Pen   Carburettor   Gunpowder   Arc Lamp   Half-n-half Clue   4. Bardeen, Shockley, Brattain   Jet Engine   Transistor   Gunpowder   Laboratory Gas Burner   Half-n-half Clue   5. Evangelista Torricelli   Bicycle   Microscope   Barometer   Power Loom   Half-n-half Clue   6. David Bushnell   Hovercraft   Submarine   Fountain Pen   Airship (rigid)   Half-n-half Clue   7. Otto   Fountain Pen   Shorthand   Gunpowder   Internal Combustion Engine   Half-n-half Clue