From the nearest telephone call office he spoke to the chief of police at Birmingham, asking him to try to trace a William Douglas who lived in Fulham Street in that city, and he was not greatly surprised when that officer, after asking him to hold on for a moment, informed him that there was no street of that name in the town.

On reaching his office at the Yard the Inspector sat down at his desk, and taking the burnt fragment of the envelope from his pocket, set himself to try and puzzle out the address. The four lines ended in ‘—glas’, ‘—ttage’, ‘—rton’, and ‘—von’ respectively. Of these, the ‘—glas’ at the end of the first line seemed unquestionably to be part of the name ‘Douglas’, and the Inspector was therefore not without hope that this was the man’s real name.

Procuring another envelope of the same size, Tanner laid the charred fragment on the top, and endeavoured to estimate from the spacing of the ‘—glas’, what had preceded it. It was probable that, as there was no ‘Esq.’, the line had commenced with ‘Mr’. But ‘Mr’ alone, or even ‘Mr W.’ or ‘Mr Wm.’ would not fill the line. Tanner tried to write ‘Mr William Dou—’ in Sir William’s hand, and, as this seemed exactly the size of the required space, he assumed this had been the first line.

The ‘—ttage’ at the end of the second line immediately suggested the word ‘Cottage’. Writing in the ‘Co—’ in the same manner as the ‘Mr William Dou—’ he found there would be left before it space for a word of six or seven letters. Though his conclusions on this second line were admittedly only guesswork, he still felt fairly sure of his ground so far.

So many towns and villages ended with the letters ‘—rton’, Tanner felt it useless to work at the third line. He therefore transferred his attention to the fourth, merely noting that as the third did not end in ‘Street’ or ‘Road’, the balance of probability was against the fourth line containing the name of a town. But this, of course, was by no means certain.

The fourth line ended in ‘—von’, and, considering the suggestion made by the third line, Tanner determined to begin, by assuming this was the name of a county. He got down an atlas and went over all the counties in the three kingdoms. Two only ended in ‘—von’—Carnarvon and Devon. He tried spacing these in and found neither would suit. ‘Devon’ was out of the question, as the ‘D’ came after the ‘n’ of the third line, and ‘Carnarvon’, which fitted better, was still obviously too short.

He set to work then upon the towns. It was clear that as the name was the last in the address, the town must either be of considerable importance, or else lie close to Halford. Tanner chose the latter alternative first, and went over all the towns near Sir William’s residence. He could find none to fit.

Sending for a Post Office Directory, in which towns with head offices—and therefore important—are printed in capitals, the Inspector laboriously ran his eye down the closely printed pages, searching for names in capital letters ending in ‘—von’. There were scores in ‘—ton’, some in ‘—don’, some in ‘—ven’, and ‘—van’, but he was amazed to find only two in ‘—von’—‘Carnarvon’ and ‘Stratford-on-Avon’. Of these, while ‘Carnarvon’, as he had already found, seemed too short, ‘Stratford-on-Avon’ was clearly a good deal too long.

As he slowly pondered the matter, another idea occurred to him. ‘Devon’, he recollected, was rarely written alone, ‘North’ or ‘South’ was usually prefixed. To space out ‘North De—’ was the work of a moment. And then he felt more satisfied, for these letters seemed exactly to fill the required space.

While he fully realised that the evidence was by no means conclusive—in fact, was but slightly removed from a guess—he thought the probabilities of the last word being ‘Devon’ were such, that it would be worth while investigating on the basis of this assumption before trying any of the other names. The next question therefore became, What, if any, places in Devon ended in ‘—rton’?