One solution alone suggested itself, returned continually to the point of his pencil and, in the end, appeared to him the right one, because it agreed with the logic of the facts and also corresponded with the general circumstances.
Admitting that the page in the album contained each of the letters of the alphabet once and once only, it was probable, it was certain that he had to do with incomplete words and that these words had been completed with letters taken from other pages. Given these conditions, and allowing for the possibility of a mistake, the puzzle stood thus:
R E P O N D . Z—CH—237
The first word was clear: "Rêpondez, reply." An E was missing, because the letter E, having been once used, was no longer available.
As for the last, unfinished word, it undoubtedly formed, with the number 237, the address which the sender gave to the receiver of the letter. He was advised to fix the day for Saturday and asked to send a reply to C H 237.
Either C H 237 was the official number of a poste restante or else the two letters C H formed part of an incomplete word. Shears turned over the leaves of the album: nothing had been cut from any of the following pages. He must, therefore, until further orders, be content with the explanation hit upon.
"Isn't it fun?"
Henriette had returned.
He replied: