The state had to look over and protect the natural sources of water.

After a little search they were successful in finding a place with a natural source of water.

Even then, he said, a natural source could cause a cluster of cases.

"It may take hours to find a natural source of water and a safe place to camp."

The energy of the painting seems to come from the artist's ability to make himself a natural source.

With no natural source this high, its water is pumped up about 1,600 feet.

This area provided a natural source of the needed clay.

The desert offered few natural sources of food and water in most areas.

The 10% came from natural sources other than the substance concerned.

However, there are no significant natural sources of this substance on Earth.