Phillips, and also Mr. Bacon, of the firm of Perkins and Co., to undertake the task; which they did. The new oleaginous ink, produced on the above application, seemed at first to answer well; but past failure led me to doubt present results. Meantime, endless suggestions were coming from various quarters, all requiring to be more or less considered, and many plausible enough to deserve trial, but all ending, sooner or later, in failure. The worry of this continued succession of hope and disappointment made me at last almost afraid to enter my office; where I foreknew that some untoward report must be awaiting me. At length I drew up a Report, containing all the information then possessed, and recommending, for the present, obliteration with good black printing-ink, prepared in a peculiar manner, and the printing of the adhesive stamps in coloured inks—blue, as before, for the twopenny ones, but red for the penny ones; both colours, however, to be oleaginous, but at the same time destructible; my aim being to render the obliteration so much more tenacious than the postage stamp that any attempt at removing the former must involve the destruction of the latter. The new labels being thus far provided for, anxiety remained as to the stock of all kinds still on hand. It was still hoped, however, that thoroughly good printer’s-ink would answer the purpose sufficiently to prevent any serious abuse; but within three weeks from the date of my Report, a chemist named Watson had succeeded completely in the removal of this obliteration also. His process, however, though very simple, inexpensive, and effectual in relation, at least, to the black stamp, proved so slow as to demand nine minutes per label in its application; so that the danger to be apprehended was not very formidable. To prevent even this, however, Mr. Watson proposed an obliterating ink which he regarded as quite irremovable. So indeed it proved; but nevertheless its use was inadmissible, because it both injured the paper and obliterated the writing in its neighbourhood. Mr. Watson’s attempts to remove the black ink from the red stamp seemed, after an interval of some weeks, to succeed. Fortunately, the success was only apparent, nor, so far as I am aware, has practical success been subsequently achieved by any one; so that the mode then adopted still remains in satisfactory use. Still, however, temporary difficulties remained, and, yet worse, increased: the process of removing black from black, which Mr. Watson could carry on but slowly, my clerk, Mr. Ledingham, whose ingenuity had dealt effectually with many previous devices, succeeded in carrying on at the rate of one per minute; a rate quite quick enough to make knavery very profitable. After much thought I hit upon a device which is thus recorded in my Journal:—