Its present owner, however, happened to notice in a museum what appeared to be a duplicate of the manuscript in his possession, and when a chemical test was applied to the ink upon the latter the pigment was quite unaffected. Hence there could be no doubt as to its being a copy of the original reproduced by lithography. Cases in which it is necessary to distinguish between iron-gall writing inks and printing or other carbon inks occur from time to time in criminal investigations. As a recent example a case that was tried a few months ago may be mentioned. The chief clerk of a firm of merchants had for a considerable time been defrauding his employers, and when suspicion at length fell upon him, endeavoured to conceal his doings by falsifying the entries of previous years in the ledger. In order to do this it was necessary to abstract certain pages in a particular part of the ledger and to substitute the necessary alterations. Then, finding that the ink of the writing would appear too new, and thus invite inquiry, he added a small amount of Indian ink to an ordinary writing ink, and thus obtained a mixture, which gave an immediate effect of age to the writing. To the naked eye there was nothing to show that these pages had not been written on the dates mentioned on them, three or four years previously, but on applying a weak bleaching agent the fraud was at once made obvious. The iron-gall part of the pigment faded away, but the particles of carbon that had formed the basis of the Indian ink were left, and their nature could easily be recognised under the microscope. The entries on the other pages in the ledger, which had been written in ordinary writing were completely bleached in the test. A very curious illustration of the difficulties that beset the forger of ancient documents was afforded by the trial of Humphreys in 1839 in Edinburgh. The prisoner was the claimant to the earldom of Stirling, and in support of his claim had produced a number of documents supposed to date back to the seventeenth and early eighteenth centuries. One of these purported to be a portion of a charter granted by King Charles I to the first Earl of Stirling in 1639, permitting the succession to the earldom to descend through the daughters of the house. As witness to this there was appended the signature of Archbishop Spottiswood described as "our Chancellor," whereas as a matter of history the seal had been handed to the Marquis of Hamilton a year prior to the date of the pretended charter. There were also various other anachronisms in the document, such as margins in red ink, which were not used before 1780. Scientific evidence was also given that the ink upon the pretended charter was not old ink, but ink that had been treated in such a manner as to appear old.