The youth tried to smile, though the effort tortured him.  “It was worth ’arf a thick ’un at least, guv’nor.”

Hume gave him two sovereigns, and the runner could not have been more taken aback had the donor “landed him” on the sound jaw.

“And now, you,” said Brett to the cabman.  “What did you see?”

“Me!” with a snort of indignation.  “Little over an hour ago I sawr a smawt keb an’ a tidy little nag wot I gev thirty quid fer at Ward’s in the Edgware Road a fortnight larst Toosday.  And wot do I see now?  Marylebone Work’us fer me an’ the missis an’ the kids.  My keb gone, my best hoss killed, an’ a pore old crock left, worth abart enough to pay the week’s stablin’.  I see a lot, I do.”

The man was telling the truth.  He was blear-eyed with misery.  Brett looked at Hume, and the latter rang a bell.  He asked the waiter for a pen and ink.

“How much did your cab cost?” he said to the driver, who was so downcast that he actually failed to correctly interpret David’s action.  The question had to be repeated before an answer came.

“It wasn’t a new ‘un, mister.  I was just makin’ a stawt.  I gev fifty-five pound fer it, an’ three pun ten to ’ave it done up.  But there!  What’s the use of talkin’?  I’m orf ’ome, I am, to fice the missis.”

“Wait just a little while,” said David kindly.  “You hardly understand this business.  The madman who attacked us meant to injure me, not you.  Here is a cheque for L100, which will not only replace your horse and cab, but leave you a little over for the loss of your time.”

Winter caught the dazed cabman by the shoulder.

“Billy,” he said, “you know me.  Are you going home, or going to get drunk?”

Billy hesitated.

“Goin’ ’ome,” he vociferated.  “S’elp me—­”

“One moment,” said Brett.  “Surely you have some idea of the appearance of the rascal who pulled your horse over?”

The man was alternately surveying the cheque and looking into the face of his benefactor.

“I dunno,” he cried, after a pause.  “I feel a bit mixed.  This gentleman ’ere ’as acted as square as ever man did.  ’E comes of a good stock, ’e does, an’ yet—­I ’umbly ax yer pawdon, sir—­but the feller who tried to kill you an’ me might ha’ bin yer own brother.”

CHAPTER XXIII

MARGARET’S SECRET

The waiter managed to remove the most obvious traces of Brett’s escapade in the gutter, and incidentally cleaned the stick.

It was a light, tough ashplant, with a silver band around the handle.  The barrister held it under a gas jet and examined it closely.  Nothing escaped him.  After scrutinising the band for some time, he looked at the ferrule, and roughly estimated that the owner had used it two or three years.  Finally, when quite satisfied, he handed it to Winter.

“Do you recognise those scratches?” he said, with a smile, pointing out a rough design bitten into the silver by the application of aqua regia and beeswax.