c current would be cut
off at the meter. So far as I can judge, some two or three units must
have been consumed during my visit. There could not be many less than ten
lights burning for an hour. Now, those units must show on the meter. Can
you read an electric meter?"

"My dear fellow, there is nothing easier."

"Then let us go down into the basement and settle the matter. There is
pretty sure to be a card on the meter made up to the day when the last
tenant went out. See, the supply is cut off now."

As Steel spoke he snapped down the hall switch and no result came. Down
in the basement by the area door stood the meter. Both switches were
turned off, but on Bell pressing them down Steel was enabled to light
the passage.

"There's the card," Bell exclaimed. "Made up to 25th June, 1895, since
when the house has been void. Just a minute whilst I read the meter. Yes,
that's right. According to this the card in your hand, provided that the
light has not been used since the index was taken, should read at 1521.
What do you make of the card?"

"1532," David cried. "Which means eleven units since the meter was last
taken. Or, if you like to put it from your point of view, eleven units
used the night that I came here. You are quite right, Bell. You have
practically convinced me that I have been inside the real 219 for the
first time to-day. And yet the more one probes the mystery the more
astounding does it become.... What do you propose to do next?"

"Find out the name of the last tenant or owner." Bell suggested.
"Discover what the two houses were used for when they were occupied by
one person. Also ascertain why on earth the owners are willing to let a
house this size and in this situation for a sum like L80 per annum. Let
us go and take the keys back to the agents."

Steel was nothing loth to find himself in the fresh air again. Some
progress had been made like the opening of a chess-match between masters,
and yet the more Steel thought of it the more muddled and bewildered did
he become. No complicated tangle in the way of a plot had ever been
anything like the skein this was.

"I'm like a child in your hands," he said. "I'm a blind man on the end of
a string; a man dazed with wine in a labyrinth. And if ever I help a
woman again--"

He paused as he caught sight of Ruth Gates's lovely face through the
window of No. 219. Her features were tinged with melancholy; there was a
look of deepest sympathy and feeling an