Americans tend to think of Benjamin Franklin as a tinkerer and dabbler: inventor of bifocals and the Franklin stove, kite flier, and quaint aphorist of Poor Richard's Almanack.
In fact, the man behind the popular iconography was energetic, insatiably curious, and prodigiously active. Even in the midst of strenuous diplomatic labors on the part of the infant American republic, Franklin squeezed science into every free moment of his time.
His voluminous correspondence with scientists worldwide includes observations of clouds, storms, ocean currents (he mapped the Gulf Stream), tides, rivers, sunspots, whirlwinds, lighter-than-air balloons, lead poisoning, daylight savings time, and the common cold. We saw yesterday how he anticipated the essential idea of plate tectonics. Little escaped his ravenous attention.
In Europe -- today as in his own time -- he is best known as the author of "Experiments and Observations on Electricity," a book that helped lay the foundations of electrical science. It was Franklin, for example, who discovered that electrical charge was of two kinds, which he called positive and negative.
The historian Carl Becker says of Franklin: "[Science was the] one activity from which he never wished to retire, to which he would willingly have devoted his life, to which he always gladly turned in every odd day or hour of leisure, even in the midst of the exacting duties and heavy responsibilities of his public career. Science was the one mistress to whom he gave himself without reserve."