Page:Carroll - Tangled Tale.djvu/104

88 A, she says "therefore;" AB + AD must be less than BC + CD. (There is no logical force in either "therefore." For the first, try . 1, 21, 60, 70: this will make your premiss true, and your conclusion false. Similarly, for the second, try . 1, 30, 51, 71.)

Of the five partly-right solutions, and  (who send one answer between them) make. 25 6 units from the corner instead of 5. , E. R. D. L., and leave openings at the corners of the Square, which are not in the data: moreover  gives values for the distances without any hint that they are only approximations. make the bold and unfounded assumption that there were really 21 houses on each side, instead of 20 as stated by Balbus. "We may assume," they add, "that the doors of . 21, 42, 63, 84, are invisible from the centre of the Square"! What is there, I wonder, that would not assume?

Of the five who are wholly right, I think, and deserve special praise for their full analytical solutions. picks out. 9, and proves it to be the right house in two ways, very neatly and ingeniously, but why he picks it out does not appear. It is an excellent synthetical proof, but lacks the analysis which the other four supply.