"Strange Disappearance of a Baronet" by Algernon Blackwood

Published in 1914

Baronet: a hereditary title awarded by the British Crown, below the rank of baron, but above knight bachelor. Thus part of the lesser nobility. These titles were created by James I in 1611, and sold off (the first lot in 1611 for £1,095 each, but by 1625 the price was already upped to £2,000) as a means of raising money. Today there are still over a thousand holders of the title of baronet, although the numbers have been in decline, while they are virtually never given out any more - Margaret Thatcher's son Mark was given the title, but that's the only one since 1965.

Pol Roger: a brand of champagne

pier glass: a mirror which is placed on a pier, i.e. a wall between two windows supporting an upper structure

egg-cupful: You know the joke how Americans will measure things using ANYTHING other than the metric system? Well, Blackwood was British, so it must have first started with the Brits :-P

salver: a flat heavy tray of silver, other metal or glass used for carrying or serving glasses, cups, and dishes at a table, or for the presenting of a letter or card by a servant

The picture used is "Men of the Day No.243: Caricature of Sir Philip Rose Bt.; Caption reads: Lord Beaconsfield's friend", from the May 14, 1881 issue of Vanity Fair, by Leslie Ward

To follow along: https://www.gutenberg.org/cache/epub/72928/pg72928-images.html#IV