1. Otto   Internal Combustion Engine   Microscope   Laboratory Gas Burner   Barometer   Hint Half-n-half Clue   2. Lewis E. Waterman   Internal Combustion Engine   Fountain Pen   Electronic Computer   Submarine   Half-n-half Clue   3. James Harrison, Alexander Catlin   Microscope   Airship (rigid)   Bakelite   Refrigerator   Half-n-half Clue   4. G. Ferdinand Von Zeppelin   Airship (rigid)   Stethoscope   Shorthand   Rabies Vaccine   Half-n-half Clue   5. Johann Gutenberg   Stethoscope   Bicycle   Transistor   Printing Press   Half-n-half Clue   6. Evangelista Torricelli   Barometer   Internal Combustion Engine   Ball-Point Pen   Stethoscope   Half-n-half Clue   7. Edmund Cartwright   Refrigerator   Power Loom   Barometer   Ball-Point Pen   Half-n-half Clue