To alter with a pen a 1 into a 4 is an easy task--to cut out the numeral from the _date_ in one note and insert it into another, needs only a tyro in paper-cutting; but to change the special _number_ by which each note is distinguished, is a feat only second in impossibility to trumping every court-card of every suit six times running in a rubber of whist. Yet we have seen a note so cleverly altered by this expedient, that it was actually paid by the Bank cashiers. If the reader will take a Bank note out of his purse, and examine its “number,” he will at once appreciate the combination of chances required to find, on any other note, any other figure that shall displace any one of the numerals so as to avoid detection. The “number” of every Bank note is printed twice on one line--first, on the words “I promise,” secondly, on the words, “or bearer.” Sometimes the figures cover the whole of those words; sometimes they only partly obscure them. No. 99066 now lies before us. Suppose we wished to substitute the “0” of another note for the first “9” of the one now under our eye; we see that the “9” covers a little bit of the “P,” and intersects in three places the “r,” in “Promise.” Now, to give this alteration the smallest chance, we must look through hundreds of other notes till we find an “0” which not only covers a part of the “P” and intersects the “r” in three places, but in precisely _the same_ places as the “9” on our note does; else the strokes of those letters would not meet when the “0” was let in, and instant detection would ensue. But even then the job would only be half done. The second initial “9” stands upon the “or” in “or bearer,” and we should have to investigate several hundred more notes, to find an “0” that intersected that little word exactly in the same manner, and then let it in with such mathematical nicety, that not the hundredth part of a hair’s breadth of the transferred paper should fail to range with the rest of the letters and figures on the altered note; to say nothing of hiding the joins in the paper. This is the triumph of ambidexterity; it is a species of patch-work far beyond the most sublime achievements of “Old Patch” himself.