In the first edition (vol. ii. p. 370) I gave a logical problem involving six terms, and requested readers to discover the laws governing the combinations given. I received satisfactory replies from readers both in the United States and in England. I formed the combinations deductively from four laws of correction, but my correspondents found that three simpler laws, equivalent to the four more complex ones, were the best answer; these laws are as follows: a = ac, b = cd, d = Ef.
In case other readers should like to test their skill in the inductive or inverse problem, I give below several series of combinations forming problems of graduated difficulty.
Problem I.
- A B c
- A b C
- a B C
Problem II.
- A B C
- A b C
- a B C
- a B c
Problem III.
- A B C
- A b C
- a B C
- a B c
- a b c
Problem IV.
- A B C D
- A b c D
- a B c f
- a b C f