Holmes on the Astronomer Herschels

Caroline also remembered long philosophical arguments at home in the evenings, when the brothers returned after concerts. She would lie awake in her bedroom, trying not to fall asleep and secretly delighting in William's quiet, calm voice steadily contradicting Jacob's furious out-bursts. According to her the names of Leibniz and Newton' were shouted from the parlour 'with such warmth that my Mother's interference became necessary: When their father was at home these conversations on philosophical subjects became even more rowdy, and would frequently last till dawn. The combination of Leibniz and Newton suggests that William and Jacob were arguing about the rival virtues of calculus (a mathematical system invented by Leibniz) and fluxions (a similar system invented — but jealously guarded — by Newton). Both systems produced the new mathematics of curves and gradients, essential to the astronomical calculation of planetary orbits and the elongated ellipses of comets. It was an unusual household.
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In November 1755 the five-year-old Caroline witnessed a strange portent of disruption in the after-shock of the Lisbon earthquake, which amazingly travelled as far as Germany. As she remembered it, the whole barracks shook. 'I saw both my parents standing aghast and speechless ... my brothers came running in ... all [the family] being panic-struck by the earth quake: 23 This earthquake, which killed over 30,000 people in Lisbon and shook cities throughout Europe, seemed to many to call into question the idea of God (or Nature) as a benevolent Providence, and to be a sign that a new kind of scientific knowledge was required. Among many speculative works, it inspired Voltaire's Candide. Caroline always retained a superstitious horror of earthquakes, and said she felt one years later when she stood by her father's deathbed.24 In the spring of 1756, when William was seventeen and Caroline was six, the Hanover Foot Guards were posted to England, to serve under their ally the Hanoverian King George II. It was the outbreak of a long, desultory and financially draining conflict with the French that would become the Seven Years War.