metallic

It is magnificent!” said Cavalcanti, who was quite confounded at the metallic sound of these golden words.

“One moment,” said Holmes, “are you sure about this whistle and metallic sound?

“When you combine the ideas of whistles at night, the presence of a band of gipsies who are on intimate terms with this old doctor, the fact that we have every reason to believe that the doctor has an interest in preventing his stepdaughter’s marriage, the dying allusion to a band, and, finally, the fact that Miss Helen Stoner heard a metallic clang, which might have been caused by one of those metal bars that secured the shutters falling back into its place, I think that there is good ground to think that the mystery may be cleared along those lines.”

The metallic clang heard by Miss Stoner was obviously caused by her stepfather hastily closing the door of his safe upon its terrible occupant.