Henri Pitot, as you may well guess, was French. He was born in a place called Aramon in 1695, and died there 76 years later in 1771.
In between, in 1718, he was elected a member of the French Academy of Sciences. Oblivion was his likely destiny until in 1732 he designed a neat little device which, two centuries later, was adapted to measure the speed of aircraft.
Pitot was mainly interested in the rate of flow of water, and it was in this context that he invented what has come to be called the "Pitot tube". It works on the principle that if an open tube, of the kind into which they put the sweets called "Smarties" nowadays, is faced into the wind, the pressure on the "open" end increases with the windspeed. Indeed the total pressure at the orifice is a combination of the pressure due to the flow of air, which meteorologists call "dynamic" pressure, and the normal barometric pressure of the atmosphere - the so-called "static" pressure.
The Pitot tube on an aircraft is often mounted on the side of one of the engines, underneath the wings. Elsewhere on the fuselage, suitably sheltered from the airflow sweeping past, is a pressure sensor to measure atmospheric pressure in the normal way, the "static" pressure.
The difference between the two recorded values represents dynamic pressure, and this is a measure of how quickly the surrounding air is flowing past the aircraft - and therefore of how fast the aircraft is flying.
But as a former Taoiseach once allegedly enquired, "That's all very well in practice, but does it work in theory?" - and of course it does.
Bernoulli's Theorem, with which all readers of this column will be quite familiar, tells us that dynamic pressure is proportional to the square of the velocity of the fluid: in other words, if air speed doubles, the pressure difference between the two sensors increases fourfold. Clearly, it would seem, if you can measure the two pressures accurately enough, it should be a simple matter to calculate how fast the aircraft is flying.
But nothing concerning the atmosphere is simple. The dynamic pressure exerted on the open tube depends also on the density of the impinging air, and therefore on the temperature of the atmosphere outside the aircraft: the instrument must be calibrated to provide the required correction. And even then, the Pitot tube just gives the speed of the aircraft relative to the air surrounding it; to calculate the "ground speed" requires a knowledge of the strength and direction of the wind in the vicinity - and thereby hangs another tale.