Tag Archives: biology

“Repair this model, if you please.” These words were spoken to James Watt, an instrument maker at the University of Glasgow, Scotland, in 1764. The model showed how a steam engine worked, but what a steam engine! The original engine of which this miniature working model was a copy, was heavy and clumsy. Worse than that, it was extremely wasteful of the steam that ran it and therefore of the coal that was burned to generate the steam. Such steam engines, built by an English blacksmith named Newcomen, had been used for 40 years, but only in mines to pump …

In the first years of Spartan peace, Greece was filled with wandering soldiers. Their little cities needed them no more. The new governments, which Spartans appointed, looked on them as men who might make trouble and were quick to get rid of them. Homeless and with no way to earn a living, the old campaigners roamed from place to place. They became soldiers of fortune, men who fought for any general or city that offered pay and three meals a day. In 401 B. C., ten thousand of them hired themselves out to Cyrus, a prince of Persia, who hoped …