"But how--why--"

"You see, I had a fact to go upon. You had noticed that your so-called
bride's gloves did not fit her; the boy below, that her shoes were so
tight she hobbled. That set me thinking. A woman of Mrs. Ransom's
experience and judgment would not be apt to make a mistake in two such
important particulars; which, taken with the veil and the promise she
exacted from you not to address or touch her during your short ride to
the hotel, led me to point my inquiries so that I soon found out that
your wife had had the assistance of another woman in getting ready for
her journey and that this woman was her own maid who had been with her
for a long time, and had always given evidence of an especial attachment
for her. Asking about this girl's height and general appearance (for the
possibility of a substitution was already in my mind), I found that she
was of slight figure and good carriage, and that her age was not far
removed from that of her young mistress. This made the substitution I
have mentioned feasible, and when I was told that she was seen taking her
hat and bonnet into the bride's room, and, though not expected to leave
till the next morning, had slid away from the house by the basement door
at the same moment her mistress appeared on the front steps, my
suspicions became so confirmed that I asked how this girl looked, in the
hope that you would be able to recognize her, through the description,
as the woman you had seen sitting in Reception-room No. 3. But to my
surprise, Mrs. Fulton had what was better than any description, the
girl's picture. This has simplified matters very much. By it you have
been able to identify the woman who attempted to mislead you in the
reception-room, and I the person who rode here with you from Mr. Fulton's
house. Wasn't she dressed in brown? Didn't you notice a similarity in her
appearance to that of the very lady you were then seeking?"