his guest, though armed with the best of credentials, was quite
unknown to him otherwise, and that, perhaps, he had acted unwisely in
inviting a stranger to his house without making some preliminary
inquiry. This reversal of their roles was a conceit so ludicrous that
Theydon smiled too.

At any rate, he meant now to pursue an unpleasing task, and have done
with it.

"No," he said slowly. "It seems that I am the worst sort of witness in
a murder case. I may have heard, I may even have seen, the person
suspected of committing the crime, or, if that is going too far, the
person whom the police have good reason to regard as the last who saw
the poor victim alive and in ordinary conditions. But my testimony,
such as it is, is so slight and inconclusive that, of itself, no one
could hang a cat on it."

"Good gracious! That sounds interesting, though you have my sympathy.
It must be rather distressing to be mixed up in such an affair, even
indirectly."

Forbes struck precisely the right note of friendly inquiry. He wished
to hear more, and was at the same time relieved to find that Professor
Scarth had not introduced a notorious malefactor in the guise of a
young writer seeking material for an article on air-ships!

Theydon could have laughed aloud at this comedy of errors, but the
fact that at any moment it might develop into a tragedy exercises a
wholesome restraint.