very few which had not. Examining more closely still I found that the dots were disposed in three different ways: (a) in the body of the letter itself: (b) above the letter: (c) below it. There was never more than one mark in the body of the letter; but those above or below were sometimes single and sometimes double. Some letters had only the dot in the body; and others, whether marked on the body or not, had no dots either above or below. Thus there was every form and circumstance of marking within these three categories. The only thing which my instinct seemed to impress upon me continually was that very few of the letters had marks both above and below. In such cases two were above and one below, or vice versa; but in no case were there marks in the body and above and below also. At last I came to the conclusion that I had better, for the time, abandon attempting to decipher; and try to construct a cipher on the lines of Bacon's Biliteral—one which would ultimately accord in some way with the external conditions of either, or both, of those before me.
But Bacon's Biliteral as set forth in the Novum Organum had five symbols in every case. As there were here no repetitions of five, I set myself to the task of reducing Bacon's system to a lower number of symbols—a task which in my original memorandum I had held capable of accomplishment.
For hours I tried various means of reduction, each time getting a little nearer to the ultimate simplicity; till at last I felt that I had mastered the principle.
Take the Baconian biliteral cipher as he himself gives it and knock out repetitions of four or five aaaaa: aaaab: abbbb: baaaa: bbbba: and bbbbb. This would leave a complete alphabet with two extra symbols for use as stops, repeats, capitals, etc. This method of deletion, however, would not allow of the reduction of the number of sym-
