We would be able to sense it as a heat source.

Just one year earlier, however, someone had discovered a potential source of heat.

But he said scientists do not know how important this source of heat is.

It is sometimes used as a heat source during power failures.

Originally, natural gas was used as a heat source in the late 19th century.

Underneath is a heat source, often built into the table itself.

A fire can start from any small spark or heat source.

There was a heat source above them, to their left, on a pole.

There was definitely a heat source, but it could have been a house by its size.

Before we can do anything else, sir, in your plan or mine, some sources of light and heat have to be found.