"In Search of the Unknown", Book 6, by Robert W. Chambers

The Mystery of the Crimson Diamond

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0:00:00 Chapter 22
0:13:19 Chapter 23
0:41:40 Chapter 24
1:03:51 Chapter 25
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Interesting how instead of another cryptid, he went for a story of the paranormal instead.

Of course, there is no famous "Crimson Diamond", it's a fictional macguffin for this story. The Koh-i-noor and the Regent are, however, real diamonds of note.

$25,000 in 1904 (the year this story was published), using the CPI to adjust for inflation, would be worth $860K today!! Using other measures, like relative wages or per capita GPD, it would be worth $4 to $6 million dollars. Either way, that's an insane reward, even allowing that the gem is priceless. Imagine how insanely wealthy the narrator of this story must be to offer a reward like that!!

I know my pronunciation of Scheldt is not the proper Dutch one, but it is the American pronunciation of it. Deal with it :-P

Mr. Bones and Mr. Tambo were characters in a minstrel show.

I'm not familiar with the "Pythagorean craze" in Boston to which he refers, it is likely fictional as a quick google search doesn't turn up anybody obvious. The "Scientific and Religious Trust Company" certainly appears to be fiction, at the very least.

Harold says it's the 19th century, but then says that President Roosevelt is alive. We already established way back in chapter 15 that the date should be 1904. Theodore Roosevelt was president in 1904 (indeed, from 1901 to 1909), so that checks. Which means Harold should have said it's the 20th century.

sough - (of the wind in trees, the sea, etc.) make a moaning, whistling, or rushing sound.

mackintosh - a form of waterproof raincoat, first sold in 1824, made of rubberised fabric.

postprandial = during or relating to the period after dinner or lunch

The pictures used are:

Chapter 22: The Argyle Everglow, a 2.11-carat Fancy Red diamond, the largest red diamond in the 33-year history of the Argyle Pink. Then, a big white cat

Chapter 23: a postcard showing the Scheldt ferry on the left bank of Antwerp, circa 1910. Nels postcard company in Brussels, serie Anvers No. 130

Chapter 24: "This train is now ready to depart" from the National Archives UK. "Photograph of railway guard giving the signal to the engine driver." Photograph by RL Sirus, 1884.

Chapter 25: of Le Grand Hotel de Normandie in Paris.

To follow along: https://www.gutenberg.org/files/18668/18668-h/18668-h.htm#XXII