George Hadley

George Hadley (1685 to 1768) was an English lawyer and amateur meteorologist, born in London, who proposed the atmospheric mechanism that sustains the trade winds, now named Hadley circulation in his honour. He entered Pembroke College, Oxford, in 1700 and was called to the bar in 1709, but remained more interested in mechanical and physical studies than in law and, with his brothers John and Henry, built effective Newtonian telescopes. For seven years, succeeding William Derham, he interpreted the meteorological diaries sent to the Royal Society by observers around the world, and tried to correlate the different temperature and pressure scales then in use. Elected a Fellow of the Royal Society in 1735, he published a short paper in the Philosophical Transactions that year explaining the trade winds, in a version that, unlike Edmond Halley's of 1686, recognised the role of the Earth's rotation. His theory stayed little known and was independently rediscovered several times, and in the second half of the nineteenth century it became known as Hadley's principle.