IF George Bernard Shaw ever did make that pithy remark about concise letter-writing, then the thought was not original. As long ago as 1656, Blaise Pascal wrote in his famous anti-Jesuit polemic Lettres Provinciales: "Je n'ai fait celle-ci plus longue que parce que je n'ai pas eu le loisir de Ia faire plus courte - I have made this letter longer than usual, because I lack the time to make it short."
Pascal was born in Clermont-Ferrand in central France 374 years ago today, on June 19th, 1623. Much of his fame lies in his espousal of the Jansenist cause in 1654, when he retired to the monastery of Port Royal in Paris, adopted the ascetic mode of life, and began to rail against the Jesuits.
A few years previously, Cornelius Jansen had shocked the Catholic world by questioning orthodox views about the freedom of the will, promoting the somewhat Calvinistic notion that people are destined by God to be either saved or damned, and that ultimately only a chosen few will be eligible for salvation. It so happened that the Abbot of Port Royal had been a special friend of Jansen's, so the monastery became the focal point of one of the most celebrated heresies in European history. Pascal took to these new beliefs with gusto, and presented them in a series of brilliant writings, celebrated even still for their admirable style, the liveliness and vigour of their arguments, and the skillful ridicule he showered on his opponents.
But Pascal had been equally inventive in science and meteorology before he took to religion. At the age of 16 he formulated one of the basic theorems of projective geometry, now known as Pascal's theorem; he invented the first mechanical adding machine, and with the mathematician Pierre de Fermat he formulated the mathematical theory of probability. He also enunciated Pascal's Law, which states that fluids transmit pressure equally in all directions, and contributed to the development of the differential calculus.
His main contribution to meteorology, however, was to build on the work of Evangelista Torricelli, who in 1643 had invented the barometer. In 1648 Pascal induced his agile brother-in-law, Florin Perrier, to carry a mercury barometer up the 5,000 ft Puy-de-Dome, the highest peak of the Massif Central. The discovery that the mercury column was shorter at the top of the mountain than at its base led Pascal to infer the principle that pressure decreases gradually with height. Indeed it is in recognition of this contribution to meteorology that the unit nowadays used for atmospheric pressure is called the hectopascal - one hundred "Pascals".