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June 2024: Science History from 50, 100 and 150 Years Ago

Walking barefoot on hot stones; what makes bluebirds blue

Spirals of chemical activity form in a shallow dish of red reagent.

1974, Spiral Reaction: “Spirals of chemical activity form in a shallow dish of red reagent. A blue ring was induced by touching the surface of the solution with a hot filament, then the dish was rocked to break the ring. The free ends of the fragmented circular wave each curl around a pivot point, winding up into spirals.” Photographs were taken over eight minutes.

Scientific American, Vol. 230, No. 6; June 1974


Pleistocene Humans Found in Ukraine

“The systematic study of Pleistocene humans was first fo­­cused in France. Yet the first occupation sites to be discovered in central and eastern Eu­­rope, many of them spectacularly rich, were unearthed al­­most as long ago. The information they contain is vital to understanding how early humans survived and perhaps even thrived under ice-age conditions in Europe, perhaps best demonstrated by nearly 100 Pleistocene sites in and around the Ukraine. The earliest sites are be­­tween 80,000 and 75,000 years old.”

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Walking Barefoot on Red-Hot Stones

“In some parts of Asia the priests, in order to show their magical powers, walk on red-hot stones spread over a fierce fire, without any protection to their feet. This achievement has always puzzled scientists. Many times the feet have been closely examined and have not shown any signs of being burned. The real explanation has only just come to light. A shallow pit is dug and in the bottom is placed the wood. This is overlaid with several layers of round stones, and the fire is lighted. When everything is ap­­par­ent­ly at a great heat the priest walks across. It has been discovered that one kind of stone, basalt, is used. This is of volcanic origin, is extremely porous and is one of the worst conductors of heat known. It is quite possible to have a lump of basalt red-hot at one end and yet cool enough to hold in the hand at the other end. Thus the cunning priest knows exactly where to put his feet.”

What Makes Bluebirds Blue?

“The average person is apt to think that all the color effects seen in nature are produced by certain substances, dyes or the like. This is true to a certain ex­­tent, as has been found in flowers. But the feathers of the blue­bird, the kingfisher and other birds are colored blue due to the dispersion of the light striking minute air cells in the horny structure of the feathers. So far no blue pigment has been ex­­tracted from these feathers.”

The Largest Map in the World

“Showing all natural and man-made features, the largest map in the world is being erected in the Ferry Building in San Francisco. The map, about two thirds completed, is 600 feet long, a ‘working model’ of the state of California, made to scale. All the rivers, bays, lakes and coastline are modeled on data from the United States Geo­detic and Geological surveys and various state departments. The mountains were colored according to survey re­­ports, and volcanic craters were formed. The lowlands were put in, including depths of water. Cliffs, marshes and beaches were reproduced in exact colors. Forests of redwood, oak and pine were made from carved fragments of sponges, painted the natural shades. Paved and un­­paved roads, railroads and all the mountain trails were carved out as trenches, and filled in with magnesite, white-­surfaced for every mile of the 6,000 of paved highways. No railroad is too small to be shown. Ties and rails were laid, tunnels were cut through the mountain walls, and trestles and bridges put in. Mine shafts were bored. Steamers and barges are placed on the rivers to indicate directions and limits of inland water traffic.”


Statue Wanders Atop the U.S. Capitol

“The iron dome of the Capitol at Washington is 300 feet high, and is surmounted by a metallic statue. It has a motion resulting from the unequal expansion of the opposite sides of the dome. The length of the oscillation from the eastern limit to the western limit is four and a half inches. In the morning the east side of the dome is rapidly heated, while the west side is chilled by radiation through the night. As the sun passes to the western side, this side is heated, but because the east side still retains a good portion of its heat, the expansion is more nearly equalized. [Overall,] the statue inclination to the west is a little greater than that toward the east.”

Covers of three issues of Scientific American from 1974, 1924 and 1874

Mark Fischetti has been a senior editor at Scientific American for 17 years and has covered sustainability issues, including climate, weather, environment, energy, food, water, biodiversity, population, and more. He assigns and edits feature articles, commentaries and news by journalists and scientists and also writes in those formats. He edits History, the magazine's department looking at science advances throughout time. He was founding managing editor of two spinoff magazines: Scientific American Mind and Scientific American Earth 3.0. His 2001 freelance article for the magazine, "Drowning New Orleans," predicted the widespread disaster that a storm like Hurricane Katrina would impose on the city. His video What Happens to Your Body after You Die?, has more than 12 million views on YouTube. Fischetti has written freelance articles for the New York Times, Sports Illustrated, Smithsonian, Technology Review, Fast Company, and many others. He co-authored the book Weaving the Web with Tim Berners-Lee, inventor of the World Wide Web, which tells the real story of how the Web was created. He also co-authored The New Killer Diseases with microbiologist Elinor Levy. Fischetti is a former managing editor of IEEE Spectrum Magazine and of Family Business Magazine. He has a physics degree and has twice served as the Attaway Fellow in Civic Culture at Centenary College of Louisiana, which awarded him an honorary doctorate. In 2021 he received the American Geophysical Union's Robert C. Cowen Award for Sustained Achievement in Science Journalism, which celebrates a career of outstanding reporting on the Earth and space sciences. He has appeared on NBC's Meet the Press, CNN, the History Channel, NPR News and many news radio stations. Follow Fischetti on X (formerly Twitter) @markfischetti

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Scientific American Magazine Vol 330 Issue 6This article was originally published with the title “50, 100 & 150 Years” in Scientific American Magazine Vol. 330 No. 6 (), p. 88