By 1846, the Smalls lighthouse had been guiding ships around the hazardous west coast of Wales for 70 years. Perched on one of the "Smalls", a cluster of low-lying lumps of rock 34 \ kilometres from St David's Head, the lighthouse's water supply was somewhat precarious. Weather permitting, a supply ship brought casks. But the keepers also collected rainwater from a dripstone and from the roof of the tower.
Shut up for months on end with only each other for company, 19th-century lighthouse keepers often took to drink. Alcoholism was rife-and suicide an all too frequent consequence. But the keepers at the Smalls had foresworn alcohol. Tea was their tipple and the taste of the water was important. So when they suspected their water was tainted, they complained loudly. That April, samples were speeding towards London, for analysis at Michael Faraday's basement laboratory at the Royal Institution.
Why would so ...
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