1. Logarithmic Tables   Karl Benz   Z. Janssen   John Napier   Otto von Guericke   Hint Half-n-half Clue   2. Submarine   David Bushnell   Nikola Tesla   Otto von Guericke   Z. Janssen   Half-n-half Clue   3. Airship (rigid)   Alessandro Volta   Z. Janssen   Nikola Tesla   G. Ferdinand Von Zeppelin   Half-n-half Clue   4. Internal Combustion Engine   John J. Loud   Otto   Z. Janssen   Kirkpatrick Macmillan   Half-n-half Clue   5. Shorthand   Roger Bacon   Kirkpatrick Macmillan   Sir Isaac Pitman   Karl Benz   Half-n-half Clue   6. Carburettor   C. F. Brush   H. W. Seeley   Z. Janssen   Gottlieb Daimler   Half-n-half Clue   7. Transistor   H. W. Seeley   John Napier   James Harrison, Alexander Catlin   Bardeen, Shockley, Brattain   Half-n-half Clue