Part 35

“I think I will step in here and get a little burnt umber,” said he.

I followed him into the shop, and while the powder-colour was being weighed and made up into a little packet I reflected profoundly. Fishing tackle and burnt umber had no obvious associations. I began to be mystified and correspondingly inquisitive.

“What do you want the burnt umber for?” I asked as soon as we were outside.

“To mix with plaster,” he replied readily.

“But why do you want to colour the plaster? And what are you going to do with it?”

“Now, Jervis,” he admonished with mock severity, “you are not doing yourself justice. An investigator of your experience shouldn’t ask for explanations of the obvious.”

“And why,” I continued, “did you want to know if I was going straight back to the chambers?”

“Because I may want some assistance later. Probably Polton will be able to do all that I want, but I wished to know that you would both be within reach of a telegram.”

“But,” I exclaimed, “what nonsense it is to talk of sending a telegram to me when I’m here!”

“But I may not want any assistance, after all.”

“Well,” I said doggedly, “you are going to have it whether you want it or not. You’ve got something on and I’m going to be in it.”

“I like your enthusiasm, Jervis,” he chuckled; “but it is quite possible that I shall merely find a mare’s nest.”

“Very well,” said I. “Then I’ll help you to find it. I’ve had plenty of experience in that line, to say nothing of my natural gifts. So lead on.”

He led on, with a resigned smile, to the station, where we were fortunate enough to find a train just ready to start. But our journey was not a long one, for at Chiswick Thorndyke got out of the train, and on leaving the station struck out eastward with a very evident air of business. As we entered the outskirts of Hammersmith he turned into a by-street which presently brought us out into Bridge Road. Here he turned sharply to the right and, at the same brisk pace, crossed Hammersmith Bridge and made his way to the towing path. As he now slowed down perceptibly, I ventured to inquire whether this was the spot on which he proposed to exhibit his super-float.

“This, I think, will be our fishing-ground,” he replied; “but we will look over it carefully and select a suitable pitch.”

He continued to advance at an easy pace, and I noticed that, according to his constant habit, he was studying the peculiarities of the various feet that had trodden the path within the last day or two, keeping, for this purpose, on the right-hand side, where the shade of a few pollard willows overhanging an indistinct dry ditch had kept the ground soft. We had walked on for nearly half a mile when he halted and looked round.

“I think we had better turn back a little way,” said he. “We seem to have overshot our mark.”

I made no comment on this rather mysterious observation, and we retraced our steps for a couple of hundred yards, Thorndyke still walking on the side farthest from the river and still keeping his eyes fixed on the ground. Presently he again halted, and looking up and down the path, of which we were at the moment the only occupants, placed the canvas case on the ground and unfastened its clasps.

“This, I think, will be our pitch,” said he.

“What are you going to do?” I asked.

“I am going to make one or two casts. And meanwhile you had better get the fishing rod fixed together so as to divert the attention of any passers by.”

I proceeded to make ready the fishing tackle, but at the same time kept a close watch on my colleague’s proceedings. And very curious proceedings they were. First he dipped up a little water from the river in the rubber mixing bowl with which he mixed a bowlful of plaster, and into this he stirred a few pinches of burnt umber, whereby its dazzling white was changed to a muddy buff. Then, having looked up and down the path, he stooped and carefully poured the plaster into a couple of impressions of a walking-stick that were visible at the edge of the path and finished up by filling a deep impression of the same stick, at the margin of the ditch, where it had apparently been stuck in the soft, clayey ground.

As I watched this operation, a sudden suspicion flashed into my mind. Dropping the fishing rod, I walked quickly along the path until I was able to pick up another impression of the stick. A very brief examination of it confirmed my suspicion. At the centre of the little shallow pit was a semicircular impression--clearly that of a half-worn boot-stud.

“Why!” I exclaimed, “this is the stick that we saw at Scotland Yard!”

“I should expect it to be and I believe it is,” said Thorndyke. “But we shall be better able to judge from the casts. Pick up your rod. There are two men coming down the path.”

He closed his “research case” and drawing the fishing-line from his pocket, began meditatively to unwind it.

“I could wish,” said I, “that our appearance was more in character with the part of the rustic angler; and for the Lord’s sake keep that float out of sight, or we shall collect a crowd.”

Thorndyke laughed softly. “The float,” said he, “was intended for Polton. He would have loved it. And the crowd would have been rather an advantage--as you will appreciate when you come to use it.”