With that strong impression Poole had to be satisfied; confirming, as it did, the testimony of the Park-keeper, Blossom, it seemed to eliminate Inez Fratten’s open Vesper. While the question was before him Poole thought he should have a look at the car, so he went round to Queen Anne’s Gate and, with Inez’s permission, had it run out of the garage. One glance was enough; it was a low, distinctly “sporting” model, with a hood which, when lifted, fitted closely over the head of the driver. Poole felt sure that Mr. Smythe could not possibly have gained the impression of a small saloon or coupé from this little whippet. He heaved a sigh of relief, thanked the chauffeur and walked away.
His next visit was to a gunsmith, a man from whom he bought his own cartridges and whom he knew to be an expert in his own line. Poole showed him the rubber bullet and asked him to suggest a weapon that might have fired it.
“We had an idea it might be a powerful catapult,” he said.
The gunsmith examined it closely, using a magnifying eye-glass. After nearly three minutes of scrutiny he removed the glass from his eye and handed it and the bullet to the detective.
“It’s not been fired from a rifled barrel; there’s no characteristic corkscrew grooving. On the other hand, there is a very faint longitudinal groove—look at it yourself—all along each side of the bullet. That suggests some running pressure along each side. I don’t see how a catapult would do that, but what about a cross-bow? The half-open barrel of a cross-bow would allow very slight expansion of the rubber in the upper half of the bullet; as the bullet lies in the open barrel, half of it appears above the wood or metal, whilst the lower half fits into the half barrel and may be ever so slightly compressed by it. When the bullet is forced along the barrel this pressure or friction in the bottom half and lack of it in the top half would be liable to cause a slight groove to appear all the way down on each side—like what you see on that bullet. That’s the solution that occurs to me, Mr. Poole; I should be interested to know sometime if it fits in with the facts.”
On his way back to Scotland Yard, Poole called in at Dr. Vyle’s house and, showing him the bullet, asked whether, if fired from something like a cross-bow, it was capable of inflicting the injury which had caused Sir Garth’s death and of making just so much mark on the flesh as subsequent examination had revealed. The police-surgeon was intensely interested by Poole’s “exhibit”; he weighed it in his hand, pinched it, struck it against his own forehead and examined it minutely through his magnifying glass.
“It’s the very thing to do the trick,” he said. “It’s soft enough to spread a bit on impact—that would both extend the surface of the blow and act as a cushion to prevent abrasion; it’s heavy enough—thanks to the lead heart—to burst, or at any rate puncture, the aneurism if the propelling force was at all strong. A good catapult or cross-bow would give that, especially at such close range; it would be pretty nearly silent, except for a sort of slap, and I should think it throws pretty straight. There’s no doubt you’ve got the weapon, inspector.”
“I’ve got the missile, anyhow, doctor, and it won’t be my fault if I haven’t got the weapon before long. Thank you.”
As he entered Scotland Yard, Poole met Sergeant Gower.
“I couldn’t find that chap Tapping on Saturday, sir,” said the Sergeant. “He’d gone off to an annual conference in Manchester the night before—all the tuning-fork testers in the country meet there every year and talk about how it’s done—excuse for a dinner and a ‘jolly,’ his wife told me it was really. Anyhow she didn’t expect him back till late Saturday night—football match in the afternoon, Arsenal playing the United up there. I went again this morning and found him in—didn’t look to me as if he knew the meaning of the word ‘jolly,’ but you never know. Anyway, he confirmed what Blossom said all right: Hessel had his arm through Fratten’s, he was sure—anyway he never hit him—Tapping swears to that and to there being no one else near enough to. He thinks somebody threw something at him.”