“Ah! that’s unfortunate,” I said, greatly disappointed; and having copied the address to which the negative and prints had been sent, I thanked her and left.

Who, I wondered, was this Baron Oberg, and what relation was he to Elma Heath?

The picture of the girl in the white blouse somehow exercised a strange attraction for me.

Have you never experienced the fascination of a photograph, inexplicable and yet forcible—­a kind of magnetism from which you cannot release yourself?  Perhaps it was the curious fact that some person had taken it from its frame on board the Lola and destroyed it that first aroused my interest; or it might have been the discovery of it in Muriel’s room at Rannoch.  Anyhow, it had for me an absorbing interest, for I often wondered whether the unknown girl who had secretly gone ashore from the yacht when I had left it was not Elma Heath herself.

Who was this Baron Oberg?  The name was German undoubtedly, yet he lived in the Russian capital.  From London to Petersburg is a far cry, yet I resolved that if it were necessary I would travel there and investigate.

At the German Embassy, in Carlton House Terrace, I found my friend Captain Nieberding, the second secretary, of whom I inquired whether the name of Baron Oberg was known, but having referred to a number of German books in his Excellency’s library, he returned and told me that the name did not appear in the lists of the German nobility.

“He may be Russian—­Polish most probably,” added the captain, a tall, fair fellow in gold spectacles, whom I had known when he was third secretary of Embassy at Rome.  His opinion was that it was not a German name, for there was a little place called Oberg, he said, on the railway between Lodz and Lowicz.

Then, after luncheon, I went to Albany Road, one of those dreary, old-fashioned streets that were pleasant back in the early Victorian days when Camberwell was a suburb and Walworth Common was still an open waste.  I found the house where Olinto lived—­a small, smoke-blackened, semi-detached place standing back in a tiny strip of weedy garden, with a wooden veranda before the first floor windows.  The house, according to the woman who kept a general shop at the corner, was occupied by two families.  The “Eye-talians,” as she termed them, lived above, while the Gibbonses rented the ground floor.

“Oh, yes, sir.  The foreigners are respectable enough.  Always pays me ready money for everythink, except the milk.  That they pays for weekly.”

“I understand that the wife has disappeared.  What have you heard about that?”

“They do say, sir, that they ’ad some words together the other day, and that the woman’s took herself off in a tantrum.  Only you can’t believe all you ’ear, you know.”

“Did they often quarrel?”

“Not to my knowledge, sir.  They were really very quiet, respectable persons for foreigners.”