1. Refrigerator   David Bushnell   James Harrison, Alexander Catlin   Kirkpatrick Macmillan   Sir Frank Whittle   Hint Half-n-half Clue   2. Stethoscope   Dr. William Stokes, Rene Laennec   Z. Janssen   Edmund Cartwright   Karl Benz   Half-n-half Clue   3. Shorthand   William Siemens   Sir Isaac Pitman   Dr. William Stokes, Rene Laennec   G. Ferdinand Von Zeppelin   Half-n-half Clue   4. Hovercraft   Roger Bacon   Sir Frank Whittle   Christopher Cockerell   Leo H Baekeland   Half-n-half Clue   5. Electric Battery   Alessandro Volta   John J. Loud   Karl Benz   H. W. Seeley   Half-n-half Clue   6. Fountain Pen   Evangelista Torricelli   Leo H Baekeland   Lewis E. Waterman   David Bushnell   Half-n-half Clue   7. Barometer   Evangelista Torricelli   John J. Loud   Dr. Alan M. Turing   David Bushnell   Half-n-half Clue