“But the flames, Cleek, the flames!” There was a tension in Merriton’s voice that spoke of nerves near to the breaking point.  Instantly Cleek was serious.  He reached out a hand and laid it upon the young man’s shoulder.  Merriton was trembling, but he steadied under the grip, just as it was meant that he should.

“See here,” Cleek said, bluntly, “you oughtn’t to work yourself up into such a state.  It’s not good for you; you’ll go all to pieces one of these days.  Those flames, eh?  Why I thought any one knew enough about natural phenomena to answer that question.  But it seems I’m wrong.  Those flames are nothing more nor less than marsh gas, Sir Nigel, evolved from the decomposition of vegetation, and therefore only found in swampy regions such as this.  Whew! and to think that here is a community that has been bowing down to these things as symbols from another world!”

“Marsh gas, Mr.—­”

“Headland, please.  It is wiser, and will help better to remember when the necessity arises,” returned Cleek, with a smile.  “Yes, that is all they are—­the outcome of marsh gas.”

“But what is marsh gas, Mr.—­Headland?” Merriton’s voice was still strained.

Cleek motioned to a chair.

“Better sit down to it, my young friend,” he said, gently.  “Because, to one who isn’t interested, it is an extremely dull subject.  However, it is better that you should know—­as you don’t seem to have learnt it at school.  Here goes:  marsh gas, or methane as it is sometimes called, is the first of the group of hydrocarbons known as paraffins.  Whether that conveys anything to you I don’t know.  But you’ve asked for knowledge and I mean you to have it.”  He smiled again, and Merriton gravely shook his head, while Mr. Narkom, dropping for the time being his air of pompous boredom, became the interested listener in every line of his ample proportions.

“Go on, old chap,” he said eagerly.

“Methane,” said Cleek, serenely, “is a colourless, absolutely odourless gas, slightly soluble in water.  It burns with a yellowish flame—­which golden tinge you have no doubt noticed in these famous flames of yours—­with the production of carbonic acid and water.  In the neighbourhood of oil wells in America, and also in the Caucasus, if my memory doesn’t fail me, the gas escapes from the earth, and in some districts—­particularly in Baku—­it has actually been burning for years as sacred fires.  A question of atmosphere and education, you see, Sir Nigel.”

“Good Heavens!  Then you mean to say that those beastly things out there are not lit by any human or superhuman agency at all!” exploded Merriton at this juncture.  “And that they have nothing whatever to do with the vanishing of Wynne and Collins?”

Cleek shook his head emphatically.