No joke. A vessel with a cargo of 80 tons of Ice has cleared out from this port for Martinique. We hope this will not prove to be a slippery speculation.The ice survived the voyage, but there was no place to store it, so ice had to be sold directly from the ship. Few islanders had any idea what to do with the ice. A restaurant owner bought ice and used it to make ice cream, which was a sensation noted in the local newspaper. The next decade was to prove difficult for Tudor. He struggled with trade embargoes, wound up in debtor's prison, contracted yellow fever on a visit to Havana trying to arrange the ice trade there, and in 1815 left again for Cuba just ahead of the sheriff, pursuing him for unpaid debts. On board with Frederic were the materials to build a proper ice house in Havana, along with Boston carpenters to erect it (earlier experiences in Cuba had soured him on local labour). By mid-March, the first shipment of ice arrived at the still unfinished ice house. Losses were originally high, but as the design was refined, dropped to just 18 pounds per hour. At that rate of melting, a cargo of 100 tons of ice would last more than 15 months undisturbed in the ice house. The problem of storage in the tropics was solved. Regular shipments of ice to Cuba and Martinique began and finally the business started to turn a profit, allowing Tudor to pay down his debts. The cities of the American south were the next potential markets, and soon Charleston, Savannah, and New Orleans had ice houses kept filled with ice from Boston. With the business established and demand increasing, Tudor turned to the question of supply. He began to work with Nathaniel Wyeth, who invented a horse-drawn “ice plow,” which cut ice more rapidly than hand labour and produced uniform blocks which could be stacked more densely in ice houses and suffered less loss to melting. Wyeth went on to devise machinery for lifting and stacking ice in ice houses, initially powered by horses and later by steam. What had initially been seen as an eccentric speculation had become an industry. Always on the lookout for new markets, in 1833 Tudor embarked upon the most breathtaking expansion of his business: shipping ice from Boston to the ports of Calcutta, Bombay, and Madras in India—a voyage of more than 15,000 miles and 130 days in wooden sailing ships. The first shipment of 180 tons bound for Calcutta left Boston on May 12 and arrived in Calcutta on September 13 with much of its ice intact. The ice was an immediate sensation, and a public subscription raised funds to build a grand ice house to receive future cargoes. Ice was an attractive cargo to shippers in the East India trade, since Boston had few other products in demand in India to carry on outbound voyages. The trade prospered and by 1870, 17,000 tons of ice were imported by India in that year alone. While Frederic Tudor originally saw the ice trade as a luxury for those in the tropics, domestic demand in American cities grew rapidly as residents became accustomed to having ice in their drinks year-round and more households had “iceboxes” that kept food cold and fresh with blocks of ice delivered daily by a multitude of ice men in horse-drawn wagons. By 1890, it was estimated that domestic ice consumption was more than 5 million tons a year, all cut in the winter, stored, and delivered without artificial refrigeration. Meat packers in Chicago shipped their products nationwide in refrigerated rail cars cooled by natural ice replenished by depots along the rail lines. In the 1880s the first steam-powered ice making machines came into use. In India, they rapidly supplanted the imported American ice, and by 1882 the trade was essentially dead. In the early years of the 20th century, artificial ice production rapidly progressed in the US, and by 1915 the natural ice industry, which was at the mercy of the weather and beset by growing worries about the quality of its product as pollution increased in the waters where it was harvested, was in rapid decline. In the 1920s, electric refrigerators came on the market, and in the 1930s millions were sold every year. By 1950, 90 percent of Americans living in cities and towns had electric refrigerators, and the ice business, ice men, ice houses, and iceboxes were receding into memory. Many industries are based upon a technological innovation which enabled them. The ice trade is very different, and has lessons for entrepreneurs. It had no novel technological content whatsoever: it was based on manual labour, horses, steel tools, and wooden sailing ships. The product was available in abundance for free in the north, and the means to insulate it, sawdust, was considered waste before this new use for it was found. The ice trade could have been created a century or more before Frederic Tudor made it a reality. Tudor did not discover a market and serve it. He created a market where none existed before. Potential customers never realised they wanted or needed ice until ships bearing it began to arrive at ports in torrid climes. A few years later, when a warm winter in New England reduced supply or ships were delayed, people spoke of an “ice famine” when the local ice house ran out. When people speak of humans expanding from their home planet into the solar system and technologies such as solar power satellites beaming electricity to the Earth, mining Helium-3 on the Moon as a fuel for fusion power reactors, or exploiting the abundant resources of the asteroid belt, and those with less vision scoff at such ambitious notions, it's worth keeping in mind that wherever the economic rationale exists for a product or service, somebody will eventually profit by providing it. In 1833, people in Calcutta were beating the heat with ice shipped half way around the world by sail. Suddenly, what we may accomplish in the near future doesn't seem so unrealistic. I originally read this book in April 2004. I enjoyed it just as much this time as when I first read it.
Raindrops keep fallin' in my face,Finally, here was proof that “it moves”: there would be no aberration in a geocentric universe. But by Bradley's time in the 1720s, only cranks and crackpots still believed in the geocentric model. The question was, instead, how distant are the stars? The parallax game remained afoot. It was ultimately a question of instrumentation, but also one of luck. By the 19th century, there was abundant evidence that stars differed enormously in their intrinsic brightness. (We now know that the most luminous stars are more than a billion times more brilliant than the dimmest.) Thus, you couldn't conclude that the brightest stars were the nearest, as astronomers once guessed. Indeed, the distances of the four brightest stars as seen from Earth are, in light years, 8.6, 310, 4.4, and 37. Given that observing the position of a star for parallax is a long-term project and tedious, bear in mind that pioneers on the quest had no idea whether the stars they observed were near or far, nor the distance to the nearest stars they might happen to be lucky enough to choose. It all came together in the 1830s. Using an instrument called a heliometer, which was essentially a refractor telescope with its lens cut in two with the ability to shift the halves and measure the offset, Friedrich Bessel was able to measure the parallax of the star 61 Cygni by comparison to an adjacent distant star. Shortly thereafter, Wilhelm Struve published the parallax of Vega, and then, just two months later, Thomas Henderson reported the parallax of Alpha Centauri, based upon measurements made earlier at the Cape of Good Hope. Finally, we knew the distances to the nearest stars (although those more distant remained a mystery), and just how empty the universe was. Let's put some numbers on this, just to appreciate how great was the achievement of the pioneers of parallax. The parallax angle of the closest star system, Alpha Centauri, is 0.755 arc seconds. (The parallax angle is half the shift observed in the position of the star as the Earth orbits the Sun. We use half the shift because it makes the trigonometry to compute the distance easier to understand.) An arc second is 1/3600 of a degree, and there are 360 degrees in a circle, so it's 1/1,296,000 of a full circle. Now let's work out the distance to Alpha Centauri. We'll work in terms of astronomical units (au), the mean distance between the Earth and Sun. We have a right triangle where we know the distance from the Earth to the Sun and the parallax angle of 0.755 arc seconds. (To get a sense for how tiny an angle this is, it's comparable to the angle subtended by a US quarter dollar coin when viewed from a distance of 6.6 km.) We can compute the distance from the Earth to Alpha Centauri as:
More and more as I pick up the pace…
1 au / tan(0.755 / 3600) = 273198 au = 4.32 light years
Parallax is used to define the parsec (pc), the distance at which a star would have a parallax angle of one arc second. A parsec is about 3.26 light years, so the distance to Alpha Centauri is 1.32 parsecs. Star Wars notwithstanding, the parsec, like the light year, is a unit of distance, not time. Progress in instrumentation has accelerated in recent decades. The Earth is a poor platform from which to make precision observations such as parallax. It's much better to go to space, where there are neither the wobbles of a planet nor its often murky atmosphere. The Hipparcos mission, launched in 1989, measured the parallaxes and proper motions of more than 118,000 stars, with lower resolution data for more than 2.5 million stars. The Gaia mission, launched in 2013 and still underway, has a goal of measuring the position, parallax, and proper motion of more than a billion stars. It's been a long road, getting from there to here. It took more than 2,000 years from the time Aristarchus proposed the heliocentric solar system until we had direct observational evidence that eppur si muove. Within a few years, we will have in hand direct measurements of the distances to a billion stars. And, some day, we'll visit them. I originally read this book in December 2003. It was a delight to revisit.