I experimented with the two groups of 20 pupils each. Neither knew any method of dealing with dates and numbers. The first group had had no training in In., Ex., and Con.; the second group had been well practised in those laws. I then gave each member of each group several very difficult cases of dates and numbers to be memorised--one example containing 24 figures. To save time and space in exposition, I have heretofore only mentioned 12 figures, or the half of the amount. All of the first group failed except one. He, however, could not memorise the 24 figures. All of the second group handled all the new examples with success, and only two of them met with much difficulty in dealing with the 24 figures. Since this decisive experiment, I have heartily recommended the method of finding relations amongst the numbers themselves, to all who are proficient in the use of In., Ex., and Con. The example of 24 figures must conclude this exposition. They represent respectively the number of the day of the month in which the first Saturday in each month falls in 1895 and 1896. To one without practice in applying analysis to figures, there seems no hope of memorising this long group of figures except by endless repetition. The 24 figures are 522641637527417426415375. Yet reflect a moment and all will be clear. Divide the 24 figures into 2 groups of 12 figures each and number the first group, divided into four sections, thus:-- (1) (2) (3) (4) 522, 641, 637, 527. Now bring the first and fourth groups into relation, and you see at once that the fourth group is larger than the first group by only _five_. Bringing the _second_ group into relation with the _third_ group, we find they differ only by _four_. Again: the third group is larger than the fourth by 100 and by 10, that is 527 becomes 637, the seven alone remaining steadfast. Beginning with the fourth group and passing to the third group we have the fourth group with 110 added. The second group is the third group with only four added, and the first group is the fourth group with only five subtracted. Thinking out these relations you can recall the groups as groups or the separate figures of each group or the entire 12 figures either forwards or backwards--and you have achieved this result by _Attention_ and _Thought_. The other twelve figures are easily disposed of. They are 417426415375. Divided into groups of three figures each we have (1) (2) (3) (4) 417 426 415 375. Bringing the first group into relation with the third group, we notice that it is larger by two--and considering the second group with the fourth group, we find that the second group is as much and one more above 400 as the fourth is below 400. Other minor matters could be noticed, as that the first two figures of each group are respectively 41--42--41--37, and that the last figure in each group is 7--6--5--5. But these relations are hardly worth observing.