Caulfield Gardens was one of those lines of flat-faced pillared, and porticoed houses which are so prominent a product of the middle Victorian epoch in the West End of London. Next door there appeared to be a children’s party, for the merry buzz of young voices and the clatter of a piano resounded through the night. The fog still hung about and screened us with its friendly shade. Holmes had lit his lantern and flashed it upon the massive door.

“This is a serious proposition,” said he. “It is certainly bolted as well as locked. We would do better in the area. There is an excellent archway down yonder in case a too zealous policeman should intrude. Give me a hand, Watson, and I’ll do the same for you.”