to make a pile, people should not know it was an artificial process and capable of turning out diamonds by the ton.  So I had to work all alone.  At first I had a little laboratory, but as my resources began to run out I had to conduct my experiments in a wretched unfurnished room in Kentish Town, where I slept at last on a straw mattress on the floor among all my apparatus.  The money simply flowed away.  I grudged myself everything except scientific appliances.  I tried to keep things going by a little teaching, but I am not a very good teacher, and I have no university degree, nor very much education except in chemistry, and I found I had to give a lot of time and labour for precious little money.  But I got nearer and nearer the thing.  Three years ago I settled the problem of the composition of the flux, and got near the pressure by putting this flux of mine and a certain carbon composition into a closed-up gun-barrel, filling up with water, sealing tightly, and heating.”

He paused.

“Rather risky,” said I.

“Yes.  It burst, and smashed all my windows and a lot of my apparatus; but I got a kind of diamond powder nevertheless.  Following out the problem of getting a big pressure upon the molten mixture from which the things were to crystallise, I hit upon some researches of Daubree’s at the Paris Laboratorie des Poudres et Salpetres.  He exploded dynamite in a tightly screwed steel cylinder, too strong to burst, and I found he could crush rocks into a muck not unlike the South African bed in which diamonds are found.  It was a tremendous strain on my resources, but I got a steel cylinder made for my purpose after his pattern.  I put in all my stuff and my explosives, built up a fire in my furnace, put the whole concern in, and—­went out for a walk.”

I could not help laughing at his matter-of-fact manner.  “Did you not think it would blow up the house?  Were there other people in the place?”

“It was in the interest of science,” he said, ultimately.  “There was a costermonger family on the floor below, a begging-letter writer in the room behind mine, and two flower-women were upstairs.  Perhaps it was a bit thoughtless.  But possibly some of them were out.

“When I came back the thing was just where I left it, among the white-hot coals.  The explosive hadn’t burst the case.  And then I had a problem to face.  You know time is an important element in crystallisation.  If you hurry the process the crystals are small—­it is only by prolonged standing that they grow to any size.  I resolved to let this apparatus cool for two years, letting the temperature go down slowly during the time.  And I was now quite out of money; and with a big fire and the rent of my room, as well as my hunger to satisfy, I had scarcely a penny in the world.

“I can hardly tell you all the shifts I was put to while I was making the diamonds.  I have sold newspapers, held horses, opened cab-doors.  For many weeks I addressed envelopes.  I had a place as assistant to a man who owned a barrow, and used to call down one side of the road while he called down the other.