At Home - Bill Bryson [152]
Then, in the 1830s, there suddenly came the miracle product the world had been waiting for: guano. Guano—bird droppings—had been used in Peru since the time of the Incas, and its efficacy had been remarked on by explorers and travelers ever since, but it wasn’t until now that anyone thought to scoop it into bags and sell it to desperate farmers in the northern hemisphere. Once outsiders discovered guano, however, they couldn’t get enough of it. A dressing of guano reenergized fields and increased crop yields by up to 300 percent. The world was seized with what came to be known as “guano mania.” Guano worked because it was packed with nitrogen, phosphorous, and potassium nitrate—which coincidentally were also vital ingredients in gunpowder. The uric acid in guano was also much valued by dyemakers. So guano became prized from lots of different directions. Suddenly there was almost nothing in the world people wanted more.
Guano was often enormously abundant where seabirds nested. Many rocky islands were literally smothered in it: deposits 150 feet deep were not unknown. Some Pacific islands were essentially nothing but guano. Trading in guano made a lot of people very rich. Schroder’s, the British merchant bank, was founded largely on the guano trade. For thirty years Peru earned practically all its foreign exchange from bagging up and selling bird droppings to a grateful world. Chile and Bolivia went to war over guano claims. The U.S. Congress brought in the Guano Islands Act, which allowed private interests to claim as U.S. territory any guano-bearing islands they found that weren’t already claimed. More than fifty were.
While guano was making life better for farmers, it had one very serious effect on city life: it killed the market in human waste. Previously, the workers who emptied city cesspits had sold the waste to farmers just outside the cities. That had helped keep costs down. But after 1847 the market for human waste collapsed, so disposal became a problem that was generally solved by tipping the collected waste into the nearest convenient river, with consequences that, as we shall see, would take decades to sort out.
The inevitable problem with guano was that it had taken centuries to accumulate but no time at all to be used up. One island off the coast of Africa containing an estimated two hundred thousand tons of guano was scraped bare in just over a year. Prices soared to almost $80 a ton. By 1850, the average farmer had the dispiriting choice of spending roughly half his income on guano or watching his yields wither. Clearly what was needed was a synthetic fertilizer—something that would feed crops reliably and economically. It was just at this point that a curious figure named John Bennet Lawes steps into the story.
Lawes, the son of a wealthy landowner in Hertfordshire, had from boyhood a passion for chemical experimentation. He turned a spare room in the family home into a laboratory and spent most of his time locked away there. In about 1840, in his midtwenties, he became curious about a puzzling quirk of bonemeal fertilizers—namely that bonemeal spread on certain soils like chalks and peats raised turnip