left alone again, to review her plan of attack by the
new light that had now been thrown on Miss Gwilt.

The information that had been gained by opening the governess's letter
pointed plainly to the conclusion that an adventuress had stolen her way
into the house by means of a false reference. But having been obtained
by an act of treachery which it was impossible to acknowledge, it was
not information that could be used either for warning the major or for
exposing Miss Gwilt. The one available weapon in Mrs. Milroy's hands was
the weapon furnished by her own returned letter, and the one question to
decide was how to make the best and speediest use of it.

The longer she turned the matter over in her mind, the more hasty and
premature seemed the exultation which she had felt at the first sight of
the Post-office circular. That a lady acting as reference to a governess
should have quitted her residence without leaving any trace behind her,
and without even mentioning an address to which her letters could be
forwarded, was a circumstance in itself sufficiently suspicious to be
mentioned to the major. But Mrs. Milroy, however perverted her estimate
of her husband might be in some respects, knew enough of his character
to be assured that, if she told him what had happened, he would frankly
appeal to the governess herself for an explanation. Miss Gwilt's
quickness and cunning would, in that case, produce some plausible answer
on the spot, which the major's partiality would be only too ready to
accept; and she would at the same time, no doubt, place matters
in train, by means of the post, for the due arrival of all needful
confirmation on the part of her accomplice in London. To keep strict
silence for the present, and to institute (without the governess's
knowledge) such inquiries as might be necessary to the discovery of
undeniable evidence, was plainly the only safe course to take with
such a man as the major, and with such a woman as Miss Gwilt. Helpless
herself, to whom could Mrs. Milroy commit the difficult and dangerous
task of investigation? The nurse, even if she was to be trusted, could
not be spared at a day's notice, and could not be sent away without
the risk of exciting remark. Was there any other competent and reliable
person to employ, either at Thorpe Ambrose or in London? Mrs. Milroy
turned from side to side of the bed, searching every corner of her mind
for the needful discovery, and searching in vain. "Oh,