He spoke in a familiar and sober fashion, but frequently employed some very happy expressions.

At first he gave an account of his own extensive labours and investigations with regard to explosive substances, and related with a laugh that he sometimes manipulated powders which would have blown up the entire district.

But, said he, in order to reassure his listeners, he was always extremely prudent.

At last he turned to the subject of that explosion in the Rue Godot-de-Mauroy, which, for some days, had filled Paris with dismay.

The remnants of the bomb had been carefully examined by experts, and one fragment had been brought to him, in order that he might give his opinion on it.