While I was thus engaged, he continued talking with Dillon in a low voice, evidently explaining to him the use to which he wished the large reflector put.

I was working quickly to undo the large package, and as the wrappings finally came off, I could see that it was some bulky instrument that looked like a huge gun, or almost a mortar.  It had a sort of barrel that might have been, say, forty inches in length, and where the breechlock should have been on an ordinary gun was a great hemispherical cavity.  There was also a peculiar arrangement of springs and wheels in the butt.

“The coats?” he asked, as he took from the wrappings of the package several rather fragile looking tubes.

I had laid them down near us and handed them over to him.  They were quite heavy, and had a rough feel.

“So-called bullet-proof cloth,” explained Garrick.  “At close range, quite powerful lunges of a dagger or knife recoil from it, and at a distance ordinary bullets rebound from it, flattened.  We’ll try it, anyway.  It will do no harm, and it may do good.  Now we are ready, Dillon.”

“Wait just a minute,” cautioned Dillon.  “Let me see first whether that chauffeur has returned.  He can run that engine so quietly that I myself can’t hear it.”

He had disappeared into the darkness toward the road, where he had despatched the car a few minutes before.  Evidently the chauffeur had been successful in his mission, for Dillon was back directly with a hasty, “Yes, all right.  He’s backing the car around so that he can run it out on the road instantly in either direction.  He’ll be here in a moment.”

Garrick had in the meantime been roughly sketching on the back of an old envelope taken from his pocket.  Evidently he had been estimating the distance of the house from the tree back of which he stood, and worked with the light of a shaded pocket flashlight.

“Ready, then,” he cried, jumping up and advancing to the peculiar instrument which I had unwrapped.  He was in his element now.  After all the weary hours of watching and preparation, here was action at last, and Garrick went to it like a starved man at food.

First he elevated the clumsy looking instrument pointed in the general direction of the house.  He had fixed the angle at approximately that which he had hastily figured out on the envelope.  Then he took a cylinder about twelve inches long, and almost half as much in diameter, a huge thing, constructed, it seemed, of a substance that was almost as brittle as an eggshell.  Into the large hemispherical cavity in the breech of the gun he shoved it.  He took another quick look at the light gleaming from the house in the darkness ahead of us.

“What is it?” I asked, indicating the “gun.”

“This is what is known as the Mathiot gun,” he explained as he brought it into action, “invented by a French scientist for the purpose, expressly, of giving the police a weapon to use against the automobile bandits who entrench themselves, when cornered, in houses and garages, as they have done in the outskirts of Paris, and as some anarchists did once in a house in London.”