Urban Planning

The city of Buenos Ayres, S. A., has received a singular proposition from two German mechanical engineers. They offer to cover the city with a huge umbrella, the base of which is to be 670 feet in diameter, the height 1500 feet, ribs of cast-iron 31 inches in circumference and 8 feet apart, and lining of wrought-iron one and a half inches thick. The great thing when raised will be one mile and a half wide. Around it will be a canal communicating with the Plate River, to carry away the water that might overflow the city. The work is estimated at the modest sum of $5,750,000.

— Albert Plympton Southwick, Handy Helps, No. 1, 1886

The Potsdam Giants

Friedrich Wilhelm I believed in stretching his military — when the Prussian king took the throne in 1713, he founded a special infantry regiment made up of taller-than-average soldiers.

“The men who stood in the first rank in this regiment were none of them less than seven feet high,” wrote Voltaire, “and he sent to purchase them from the farthest parts of Europe to the borders of Asia.” The diminutive king once told a French ambassador, “The most beautiful girl or woman in the world would be a matter of indifference to me, but tall soldiers — they are my weakness.”

They would have made an impressive force on the battlefield, but the “long guys” never saw action — and when Friedrich died in 1740 the crown prince dismissed the regiment.

Rock Music

A correspondent of Nature writes that, in roaming over the hills and rocks in the neighborhood of Kendal, near Lancaster, England, which are composed chiefly of limestone, he had often found what are called “musical stones.” They are generally thin, flat, weather-beaten stones, of different sizes and peculiar shapes, which, when struck with a piece of iron or another stone, produce a musical tone, instead of the dull, heavy, leaden sound of an ordinary stone. The sound of these stones is, in general, very much alike, but sets of eight stones have been collected which produce, when struck, a distinct octave.

— Frank H. Stauffer, The Queer, the Quaint and the Quizzical, 1882

See also The Musical Stones of Skiddaw.

Lightning Addition

A (probably apocryphal) story tells that, as a 10-year-old schoolboy, Carl Friedrich Gauss was asked to find the sum of the first 100 integers. The tyrannical schoolmaster, who had intended this task to occupy the boy for some time, was astonished when Gauss presented the correct answer, 5050, almost immediately.

How did Gauss find it?

Click for Answer

A Phantom City

In The Atmosphere (1873), Camille Flammarion quotes a M. Grellois, who was traveling in northern Algeria in the summer of 1847:

I was proceeding one very hot day on horseback, at a walking pace, between Ghelma and Bône, in company with a young friend who has since died. When we had arrived within about two leagues of Bône, toward one in the afternoon, we were suddenly brought to a halt at a turn in the road by the appearance of a marvelous picture unfolded before our eyes. To the east of Bône, upon a sandy stretch of ground which a few days before we had seen arid and bare, there rose at this moment, upon a gently sloping hill running down to the sea, a vast and beautiful city, adorned with monuments, domes, and steeples.

That sounds like a mirage, but Grellois says the travelers observed the city for nearly half an hour, and that “reason refused to admit that this was only a vision.” “Whence came this apparition? There was no resemblance to Bône, still less to La Calle or Ghelma, both distant twenty leagues at least. Are we to suppose it was the reflected image of some large city on the Sicilian coast? That seems to me very improbable.”