1. Sir Frank Whittle   Logarithmic Tables   Jet Engine   Bakelite   Ball-Point Pen   Hint Half-n-half Clue   2. Dr. William Stokes, Rene Laennec   Hovercraft   Stethoscope   Barometer   Logarithmic Tables   Half-n-half Clue   3. Leo H Baekeland   Electric Battery   Air Pump   Fountain Pen   Bakelite   Half-n-half Clue   4. Z. Janssen   Barometer   Microscope   Gunpowder   Carburettor   Half-n-half Clue   5. Dr. Wallace H. Carothers   Internal Combustion Engine   Automobiles using gasoline   Nylon   Carburettor   Half-n-half Clue   6. Johann Gutenberg   Microscope   Printing Press   Refrigerator   Arc Lamp   Half-n-half Clue   7. H. W. Seeley   Rabies Vaccine   Electric Flat Iron   Vaccination   Nylon   Half-n-half Clue