1. Internal Combustion Engine   Otto   John J. Loud   C. F. Brush   Dr. Wallace H. Carothers   Hint Half-n-half Clue   2. Electric Flat Iron   John Napier   H. W. Seeley   Sir Isaac Pitman   Andre-Marie Ampere   Half-n-half Clue   3. Jet Engine   Roger Bacon   Sir Frank Whittle   Otto   Alessandro Volta   Half-n-half Clue   4. Microscope   Z. Janssen   Edmund Cartwright   Dr. William Stokes, Rene Laennec   William Siemens   Half-n-half Clue   5. Rabies Vaccine   Louis Pasteur   Nikola Tesla   David Bushnell   John Napier   Half-n-half Clue   6. Laboratory Gas Burner   Robert Wilhelm Von Bunsen   Leo H Baekeland   Alessandro Volta   Lewis E. Waterman   Half-n-half Clue   7. Logarithmic Tables   James Harrison, Alexander Catlin   Otto von Guericke   Dr. Wallace H. Carothers   John Napier   Half-n-half Clue