“It is just these very simple things which are extremely liable tobe overlooked. However， I determined to act on the idea. I startedat once in this harmless seaman’s rig and inquired at all the yardsdown the river. I drew blank at fifteen， but at the sixteenth—Jacobson’s—I learned that the Aurora had been handed over tothem two days ago by a wooden-legged man， with some trivialdirections as to her rudder. ‘There ain’t naught amiss with herrudder，’ said the foreman. ‘There she lies， with the red streaks.’
At that moment who should come down but Mordecai Smith， themissing owner. He was rather the worse for liquor. I should not，of course， have known him， but he bellowed out his name and thename of his launch. ‘I want her to-night at eight o’clock，’ said he—‘eight o’clock sharp， mind， for I have two gentlemen who won’t bekept waiting.’ They had evidently paid him well， for he was veryflush of money， chucking shillings about to the men. I followedhim some distance， but he subsided into an alehouse； so I wentback to the yard， and， happening to pick up one of my boys on theway， I stationed him as a sentry over the launch. He is to stand atthe water’s edge and wave his handkerchief to us when they start.
We shall be lying off in the stream， and it will be a strange thing ifwe do not take men， treasure， and all.”
“You have planned it all very neatly， whether they are the rightmen or not，” said Jones； “but if the affair were in my hands Ishould have had a body of police in Jacobson’s Yard and arrestedthem when they came down.”
“Which would have been never. This man Small is a prettyshrewd fellow. He would send a scout on ahead， and if anythingmade him suspicious he would lie snug for another week.”
“But you might have stuck to Mordecai Smith， and so been ledto their hiding-place，” said I.
“In that case I should have wasted my day. I think that it is ahundred to one against Smith knowing where they live. As longas he has liquor and good pay， why should he ask questions？ Theysend him messages what to do. No， I thought over every possiblecourse， and this is the best.”
While this conversation had been proceeding， we had beenshooting the long series of bridges which span the Thames. As wepassed the City the last rays of the sun were gilding the cross uponthe summit of St. Paul’s. It was twilight before we reached theTower.
“That is Jacobson’s Yard，” said Holmes， pointing to a bristleof masts and rigging on the Surrey side. “Cruise gently up anddown here under cover of this string of lighters.” He took a pairof night-glasses from his pocket and gazed some time at theshore. “I see my sentry at his post，” he remarked， “but no sign of ahandkerchief.”
“Suppose we go downstream a short way and lie in wait forthem，” said Jones eagerly.
We were all eager by this time， even the policemen and stokers，who had a very vague idea of what was going forward.
“We have no right to take anything for granted，” Holmesanswered. “It is certainly ten to one that they go downstream， butwe cannot be certain. From this point we can see the entranceof the yard， and they can hardly see us. It will be a clear nightand plenty of light. We must stay where we are. See how the folkswarm over yonder in the gaslight.”
“They are coming from work in the yard.”
“Dirty-looking rascals， but I suppose every one has some littleimmortal spark concealed about him. You would not think it， tolook at them. There is no a priori probability about it. A strangeenigma is man！”
“Someone calls him a soul concealed in an animal，” I suggested.
“Winwood Reade is good upon the subject，” said Holmes. “Heremarks that， while the individual man is an insoluble puzzle， inthe aggregate he becomes a mathematical certainty. You can， forexample， never foretell what any one man will do， but you can saywith precision what an average number will be up to. Individualsvary， but percentages remain constant. So says the statistician.
But do I see a handkerchief？ Surely there is a white flutter overyonder.”
“Yes， it is your boy，” I cried. “I can see him plainly.”
“And there is the Aurora，” exclaimed Holmes， “and going likethe devil！ Full speed ahead， engineer. Make after that launch withthe yellow light. By heaven， I shall never forgive myself if sheproves to have the heels of us！”
She had slipped unseen through the yard-entrance and passedbetween two or three small craft， so that she had fairly got herspeed up before we saw her. Now she was flying down the stream，near in to the shore， going at a tremendous rate. Jones lookedgravely at her and shook his head.
“She is very fast，” he said. “I doubt if we shall catch her.”
“We MUST catch her！” cried Holmes between his teeth. “Heapit on， stokers！ Make her do all she can！ If we burn the boat wemust have them！”
We were fairly after her now. The furnaces roared， and thepowerful engines whizzed and clanked like a great metallic heart.
Her sharp， steep prow cut through the still river-water and senttwo rolling waves to right and to left of us. With every throb ofthe engines we sprang and quivered like a living thing. One greatyellow lantern in our bows threw a long， flickering funnel of lightin front of us. Right ahead a dark blur upon the water showedwhere the Aurora lay， and the swirl of white foam behind herspoke of the pace at which she was going. We flashed past barges，steamers， merchant-vessels， in and out， behind this one and roundthe other. Voices hailed us out of the darkness， but still the Aurorathundered on， and still we followed close upon her track.
“Pile it on， men， pile it on！” cried Holmes， looking down intothe engine-room， while the fierce glow from below beat upon hiseager， aquiline face. “Get every pound of steam you can.”
“I think we gain a little，” said Jones with his eyes on the Aurora.
“I am sure of it，” said I. “We shall be up with her in a very fewminutes.”