1. David Bushnell   Fountain Pen   Submarine   Ball-Point Pen   Logarithmic Tables   Hint Half-n-half Clue   2. Evangelista Torricelli   Gunpowder   Internal Combustion Engine   Barometer   Electronic Computer   Half-n-half Clue   3. Leo H Baekeland   Automobiles using gasoline   Barometer   Refrigerator   Bakelite   Half-n-half Clue   4. Z. Janssen   Carburettor   Microscope   Electronic Computer   Airship (rigid)   Half-n-half Clue   5. Dr. William Stokes, Rene Laennec   Carburettor   Stethoscope   Laboratory Gas Burner   Bakelite   Half-n-half Clue   6. Kirkpatrick Macmillan   Internal Combustion Engine   Rabies Vaccine   Bicycle   Logarithmic Tables   Half-n-half Clue   7. Otto   Ball-Point Pen   Internal Combustion Engine   Refrigerator   Power Loom   Half-n-half Clue