He did not see it, but he smelled it.

His nose went up in the air and quested to windward along the wind that brought the message, and he read the air with his nose as a man might read a newspaper--the salt smells of the seashore and of the dank muck of mangrove swamps at low tide, the spicy fragrances of tropic vegetation, and the faint, most faint, acrid tingle of smoke from smudgy fires.
The trade, which had laid the _Arangi_ well up under the lee of this outjutting point of Malaita, was now failing, so that she began to roll in the easy swells with crashings of sheets and tackles and thunderous flappings of her sails.

Jerry no more than cocked a contemptuous quizzical eye at the mainsail anticking above him.

He knew already the empty windiness of its threats, but he was careful of the mainsheet blocks, and walked around the traveller instead of over it.
While Captain Van Horn, taking advantage of the calm to exercise the boat's crew with the fire-arms and to limber up the weapons, was passing out the Lee-Enfields from their place on top the cabin skylight, Jerry suddenly crouched and began to stalk stiff-legged.

But the wild-dog, three feet from his lair under the trade-boxes, was not unobservant.