“Full speed ahead!” cried out Mr. Hume.

Venning pulled his lever over, and as he shot it back Compton pulled his, the two moving to and fro easily as if they had been rowing a steady stroke.

“She moves, she moves!” cried Mr. Hume, with a shout.

“Take her over the mile,” said the designer to the steersman; and he pulled out his watch with exactly the same look of calm interest he showed when presiding over the trial of the fastest craft afloat.

The shining aluminium boat answered to her helm, slipped through the muddy waters in a graceful curve, and then steadied for the straight course.

“Let her go, boys.”

The levers worked to and fro with an easy swing; there rose the hum of the chains moving easily below, and the quickened churning of the propeller blades.

The designer glanced from his watch to the bank, which was fast slipping away, and nodded his head at Mr. Hume.

“Easy all.  I think she will do;” and he nodded at Venning.  “Ten minutes.”

“Ten minutes!”

“A mile in ten minutes—­six miles an hour!”

“And it was as easy as nothing,” said Venning—­“wasn’t it, Dick?”

“Like cutting bread,” said Compton.

“Very good, I think; but you must remember that she carries no cargo.  Now we’ll try her with the sail alone, and then with the sail and screw combined, and then with the screw and oars, for you will see that I have fitted row-locks.”

Under a fair breeze the boat skimmed along at a merry pace, with no wave worth speaking of; and with the sail and screw she put on an additional four miles, and with the oars an extra three, making from nine to ten miles an hour.

“I congratulate you, Mr. Venning,” said the designer, as they stepped out, thoroughly pleased.

“I am sure, sir, we thank you,” said the boy, warmly.

“Eight,” said Mr. Hume; “and we are thoroughly pleased with the craft, every one of us.”

“She is a beauty,” put in Compton—­“a real beauty; and I think she would be perfect if a light awning could be fixed up over the after-deck.”

“That could be done easily.

“It would be an improvement, certainly,” said Mr. Hume.

“I will rig up brackets to hold the rods for the awning.”

“And we could fix up mosquito curtains round the sides.  That is A 1.  Now, what is her name to be?” And Mr. Hume looked at Venning.

He had thought of a name, and was prompt with it—­the Okapi.

“And what does that mean?” asked the builder, with a smile.

Venning explained, and the name was adopted.

“Now,” said the builder, “if Mr. Venning will come down to-morrow afternoon, my workmen will take the Okapi to pieces in his presence before packing it for delivery in the docks, and explain thoroughly how it is to be put together.  I will give orders for several extra plates with fittings to be placed in one of the divisions, so that if you have an accident you will have the material for repairing the mischief.  You understand, aluminium cannot be soldered, but you could cover a hole by means of nuts and screws.”