Burning Glass

In his meterological observations a scientist has discovered how the ionosphere can be polarized to act as prism for the sun so that it will boil lakes, fry life, and evaporate everything remaining. The Prime Minister arrives to ask the scientist to turn the secret over to his government. But he will not release the secret because of it's inherent deadliness. He arranges for half the calculations to be transmitted to an unknown person in a sealed envelope, and for his wife to commit the remainder to mind. A good thing, too. For the scientist is abducted by spies. His wife and the unknown person separately enter their calculations, and destroy a lake in the home country of the spies. The enemy, now realizing that the scientist has given others the information, release him. At the end the scientist holds tight to the secret, and his assistant bravely commits suicide to keep the secret intact.