Who made the first flight in an airplane?

We don't know his name, but he beat the Wright Brothers to it by fifty years.

He worked for Sir George Cayley (1773-1857), an aristocratic Yorkshireman and pioneer of aeronautics, who carried out the first truly scientific study of how birds fly. Cayley correctly described the principles of "lift, drag, and thrust" that govern flight and this led him to build a series of prototype flying machines. His early attempts with flapping wings (powered by steam and gunpowder engines) failed, so he turned his attention to gliders instead.

In 1804 he demonstrated the world's first model glider and, five years later, tested a full-size version--but without a pilot. More than three decades passed before he finally felt ready to trust his "governable parachute" with a human passenger. In 1853, at Brompton Dale near Scarborough, the intrepid baronet persuaded his reluctant coachman to steer the contraption across the valley. It was this anonymous employee who became the first human ever to fly in a heavier-than-air machine.

The coachman, so the story goes, was not impressed. He handed in his notice as soon as he landed, saying, "I was hired to drive, not to fly." A modern replica of Cayley's glider, now on show at the Yorkshire Air Museum, successfully repeated the flight across Brompton Dale in 1974.

But wings weren't Sir George's only legacy. With his work on the glider's landing gear, he literally reinvented the wheel. Needing something light but strong to absorb the aircraft's impact on landing, he came up with the idea of using wheels whose spokes were held at tension, rather than being carved from solid wood. These went on to transform the development of the bicycle and the car and are still widely used today.

And that wasn't all. Cayley was a remarkably prolific inventor, developing self-righting lifeboats, caterpillar tracks for bulldozers, automatic signals for railway crossings, and seat belts. Even more remarkably, he offered all these inventions for the public good, without expecting any financial reward.

The Wright Brothers made their famous flights half a century later, in 1903. They were inspired by Cayley and by another unsung hero of aviation, Otto Lilienthal (1848-96), a Prussian known as the "Glider King." He was the first person to fly consistently: in the decade before the Wright Brothers, he made more than 2,000 glider flights before falling to his death in 1896. His last words were humble and poignant: "Small sacrifices must be made."



How many legs does an octopus have?

Two.

Octopuses have eight limbs protruding from their bodies, but recent research into how they use them has redefined what they should be called. Octopuses (from the Greek for "eight feet") are cephalopods (Greek for "head foot"). They use their back two tentacles to propel themselves along the seabed, leaving the remaining six to be used for feeding. As a result, marine biologists now tend to refer to them as animals with two legs and six arms.

An octopus's tentacles are miraculous organs. They can stiffen to create a temporary elbow joint or fold up to disguise their owner as a coconut rolling along the sea floor. They also contain two-thirds of the octopus's brain--about 50 million neurons--the remaining third of which is shaped like a doughnut and located inside its head, or mantle.

Because so much of an octopus's nervous system is in its extremities, each limb has a high degree of independence. A severed tentacle can continue to crawl around and, in some species, will live for several months. An octopus's arm (or leg) quite genuinely has a mind of its own.

Each arm on an octopus has two rows of suckers, equipped with taste buds for identifying food. An octopus tastes everything that it touches. Male octopuses also have a specialized arm in which they keep their sperm. It's called the hectocotylus and is used for mating. To transfer the sperm, the male puts his arm into a hole in the female's head. During copulation the hectocotylus usually breaks off, but the male grows a new one the following year.

The way octopuses mate was first described by Aristotle (384-322 bc), but for more than 2,000 years no one believed him. The French zoologist Georges Cuvier (1769-1832) rediscovered the process in the nineteenth century and gave the hectocotylus its name. It means "a hundred tiny cups" in Greek.

Genetic variations sometimes cause octopuses to grow more than eight limbs. In 1998 the Shima Marineland Aquarium in Japan had a common octopus on display that had 96 tentacles. It was captured in nearby Matoya Bay in December 1998 but died five months later. The multi-armed cephalopod managed to lay a batch of eggs before its death. All the offspring hatched with the normal number of arms and legs, but none survived longer than a month.

Octopuses occasionally eat their own arms. This used to be blamed on stress but is now thought to be caused by a virus that attacks their nervous system.



What color are oranges?

That depends.

In many countries, oranges are green--even when ripe--and are sold that way in the shops. The same goes for lemons, mangoes, tangerines, and grapefruit.

Oranges are unknown in the wild. They are a cross between tangerines and the pomelo or "Chinese grapefruit" (which is pale green or yellow), and were first grown in Southeast Asia. They were green there then, and today they still are. Vietnamese oranges and Thai tangerines are bright green on the outside and orange only on the inside.

Oranges are subtropical fruit, not tropical ones. The color of an orange depends on where it grows. In more temperate climes, its green skin turns orange when the weather cools, but in countries where it's always hot the chlorophyll is not destroyed and the fruits stay green. Oranges in Honduras, for example, are eaten green at home but artificially "oranged" for export.

To achieve this, they are blasted with ethylene gas, a by-product of the oil industry, whose main use is in the manufacture of plastic. Ethylene is the most widely produced organic compound in the world: 100 million tons of it are made every year. It removes the natural outer green layer of an orange, allowing the more familiar color to show through.

Far and away the world's largest producer of oranges is Brazil (18 million tons a year), followed by the United States, which grows fewer than half as many. American oranges come from California, Texas, and Florida. They were often synthetically dyed until the Food and Drug Administration banned the practice in 1955.

You can't tell the ripeness of an orange by its color, no matter where it's from. If an orange goes unpicked, it can stay on the tree till the next season, during which time fluctuations in temperature can make it turn from green to orange and back to green again without the quality or flavor being affected.

The oranges you see on display in your supermarket certainly appear to be completely orange, but you may now start to worry they've been gassed. Don't.

Ethylene is odorless, tasteless, and harmless, and many fruits and vegetables give it off naturally after they're picked. Ethylene producers include apples, melons, tomatoes, avocados, and bananas. The gas isn't bad for you, but it can affect other kinds of fruit and vegetables--which is why you should keep apples...