Sir William Snow Harris was a British physician and electrical researcher, nicknamed Thunder-and-Lightning Harris, and noted for his invention of a successful system of lightning conductors for ships. It took many years of campaigning, research and successful testing before the British Royal Navy changed to Harris's conductors from their previous less effective system. One of the successful test vessels was HMS Beagle which survived lightning strikes unharmed on her famous voyage with Charles Darwin.

The second voyage of HMS Beagle, from 27 December 1831 to 2 October 1836, was the second survey expedition of HMS Beagle, made under her newest commander, Robert FitzRoy. FitzRoy had thought of the advantages of having someone onboard who could investigate geology, and sought a naturalist to accompany them as a supernumerary. At the age of 22, the graduate Charles Darwin hoped to see the tropics before becoming a parson, and accepted the opportunity. He was greatly influenced by reading Charles Lyell's Principles of Geology during the voyage. By the end of the expedition, Darwin had made his name as a geologist and fossil collector, and the publication of his journal gave him wide renown as a writer.