his shaft of death; and he killed by injecting it into the veins of his victims.  The result of air coming into contact with the circulating blood of a human being is the formation of a blood-clot, and death is instantaneous the instant the clot reaches either the brain or the heart!  That was his method.  But thank God it’s done with for ever now, and the next tenth day of the month will pass over this stricken family and leave it unscathed!”

* * * * *

“How did I know the man?” said Cleek, answering Narkom’s query, as they came down the Tor-side afoot and forged on in the direction of Lyntonhurst Old Church—­whither Captain Morford and the limousine had long ago preceded them—­with the low-dropped sun behind them and lengthening shadows streaming on before.  “Well, as a matter of fact, I never did know him until I actually touched him.  I was certain of the method, of course; but the man—­no.  I got my first suspicion of ’Uncle Phil’ when I heard him speak.  I knew I had heard that voice somewhere, and I realised that it was much too young a voice for a man who appeared—­and must be, if he were the real ’Uncle Phil’—­extremely old; but it was only when I saw his hand, and the peculiar knotted and twisted little finger that I really knew who he was.  What’s that?  The soap?  Well, of course I knew that if, as I suspected, someone in the house was the real culprit, an attempt would be made to make it look as though the criminal entered from without, so naturally the window would be opened, and something of some sort would be smeared on the sill—­something that wouldn’t blow away and wouldn’t wash off in the event of a sudden rainstorm coming up.  Soap would do—­and soap is always handy in a bedroom.  I knew whose hand had made the smear as soon as I looked at the cake of soap in ‘Uncle Phil’s’ room—­it was badly rubbed on one side where it had been scraped over the stone coping and along the outer edge of the sill where—­Pardon me:  this is the turning—­I leave you here.  Pick me up at the inn of the Three Desires in an hour’s time, please, and we’ll motor back to town together.  So long!”

And swung round into the branching lane and down the green slope, and round under the shadow of Lyntonhurst Old Church to the quiet country road and the lich-gate where Ailsa Lorne was waiting.

CHAPTER XXXV

She was sitting in the very same place she had occupied when first he saw her this morning, with the cypress tree and the roof making shadows above and about her; and now, as then, she rose when she heard the latch click and came toward him with hands outstretched and eyes aglow and little gusts of colour sweeping in rose waves over throat and cheeks.

“Oh, to think that you have solved it!  To think that it is the end!  And to think that it was he—­that dear, kind ‘uncle’ of whom they all were so fond!” she said.  “I could scarcely believe it when Captain Morford brought the news.  It made me quite faint for the moment—­it was so unexpected, so horrible!”