had finished with it.

As to the actual manner of his betrayer's death, the outraged husband
found it difficult to make up his mind. It was not to be prompt, nor
was unnecessary suffering to be avoided. At first he favoured a pair of
"infernal" opera-glasses that concealed a couple of steel points which,
by means of a spring, would dart out into the eyes of anyone using them
and destroy their sight. This rather elaborate and uncertain machine was
abandoned later in favour of a trap for catching wolves. This was to be
placed under the table, and seize in its huge iron teeth the legs of the
victim. In the end simplicity, in the shape of a hammer and sword-stick,
won the day. An assistant was taken in the person of Lucien Fenayrou, a
brother of Marin.

This humble and obliging individual, a maker of children's toys,
regarded his brother the chemist with something like veneration as the
gentleman and man of education of the family. Fifty francs must
have seemed to him an almost superfluous inducement to assist in the
execution of what appeared to be an act of legitimate vengeance, an
affair of family honour in which the wife and brother of the injured
husband were in duty bound to participate. Mme. Fenayrou, with
characteristic superstition, chose the day of her boy's first communion
to broach the subject of the murder to Lucien. By what was perhaps more
than coincidence, Ascension Day, May 18, was selected as the day for the
crime itself. There were practical reasons also. It was a Thursday and
a public holiday. On Thursdays the Fenayrou children spent the day with
their grandmother, and at holiday time there was a special midnight
train from Chatou to Paris that would enable the murderers to return to
town after the commission of their crime. A goat chaise and twenty-six
feet of gas piping had been purchased by Fenayrou and taken down to the
villa.

Nothing remained but to secure the presence of the victim. At the
direction of her husband Mme. Fenayrou wrote to Aubert on May 14, a
letter in which she protested her undying love for him, and expressed
a desire to resume their previous relations. Aubert demurred at first,
but, as she became more pressing, yielded at length to her suggestion.
If it cost him nothing, Aubert was the last man to decline an invitation
of the kind. A trip to Chatou was arranged for Ascension Day, May 18, by
the train leaving Paris from the St. Lazare Station, at half-past eight
in the evening.