Espy had an ardent desire for knowledge and commenced teaching school as a means to obtaining a classical education at Transylvania University, Lexington, Kentucky.

He soon, however, had his attention drawn to natural science and about 1828 he began his studies and investigations into the cause of storms which made him, at that time, the foremost American meteorologist.

In 1833 he wrote a summary of his theory of the upward movement of the air in storms (convection) and of their self-sustaining power from the evolution of latent heat.

He convinced the Pennsylvania legislature to appropriate $4,000 to equip an observer in each county with barometer, thermometers, and rain gage.

In this book Espy proposed to burn Appalachian forests to make it rain, is perhaps the earliest idea for climate engineering.