1. Otto   Airship (rigid)   Barometer   Internal Combustion Engine   Transistor   Hint Half-n-half Clue   2. John J. Loud   Ball-Point Pen   Logarithmic Tables   Barometer   Refrigerator   Half-n-half Clue   3. John Napier   Gunpowder   Stethoscope   Power Loom   Logarithmic Tables   Half-n-half Clue   4. Dr. William Stokes, Rene Laennec   Microscope   Stethoscope   Gunpowder   Jet Engine   Half-n-half Clue   5. Louis Pasteur   Power Loom   Ball-Point Pen   Stethoscope   Rabies Vaccine   Half-n-half Clue   6. Gottlieb Daimler   Microscope   Logarithmic Tables   Carburettor   Jet Engine   Half-n-half Clue   7. James Harrison, Alexander Catlin   Jet Engine   Refrigerator   Laboratory Gas Burner   Power Loom   Half-n-half Clue