From the stream he then got a number of stones, and put them into the fire until they became intensely hot.

Then with two sticks he raked them out, and dropped them into the water.
The natives yelled with astonishment as they saw the water fizz and bubble, as the stones were thrown in.

More were added until the water boiled.

Then the yams, cut into pieces, were dropped in, more hot stones added to keep the water boiling, and when cooked, the yams were taken out.

When sufficiently cooled, the boys distributed the pieces among the chiefs, and again the signs of satisfaction showed that cooked vegetables were appreciated.