A book review by Dick Luecke
British author Richard Holmes won laurels for his biographies of the Romantic poets. In Age of Wonder he extends his talents to Europe’s second great epoch of scientific discovery—a period roughly from the late 1760s through the 1820s. Holmes describes this fruitful era of science through the lives of self-taught pioneers: Joseph Banks, who traveled to Tahiti with Cook, studied the flora and fauna and went native in the new-found paradise; Humphrey Davy, whose experiments and madcap inhalations of gases formed a cornerstone of modern chemistry; the English and French balloonists who severed the bonds of gravity for the first time; Mungo Park and his misadventures in dark Africa; and Mary Shelley, creator of Frankenstein.
The real “stars” of Holmes’ book for our readers, however, are William Herschel, his sister Caroline, and his son, John. No single family has contributed so much to astronomy and on so many different fronts—from telescope making, to sky mapping, to cosmic theory, to the discovery of a planet, thousands of nebulae and double stars, and many comets.
Frederick William Herschel (1738-1822) emigrated as a 19-year-old from Germany to England in the train of the Hanoverian monarchy (George II). A musician by training, he built a modest career as a performer, composer, and teacher of oboe, guitar, organ and harpsichord. His true passion, however, was the night sky. He educated himself by attending lectures, poring over Flamsteed’s star atlas, and by assimilating Astronomy Explained Upon Principles of Sir Isaac Newton, by James Ferguson, the Patrick Moore of the eighteenth century.
Holmes describes Herschel’s early observations from his garden, where he struggled with a collection of purchased and rented refractors, none of which proved satisfactory. Unlike the professional astronomers of his day, this newcomer aimed to reach beyond the planets and bright neighborhood stars into deep space. For this, better tools were needed.
Because most reflector instruments of the time were of 3-inch apertures or less, Herschel set about building his own, learning by trial and error. Using a homemade forge and molds of dried horse dung (yes, horse dung), he cast mirrors of tin-brass alloy and polished them in non-stop sessions lasting upwards of 16 hours! As Holmes explains, “If the polishing paused for even a few seconds in the final stages, the metal would harden and mist over, and the mirror would be useless.” Herschel’s younger sister, Caroline, who would be his helpmate throughout his long career, “provisioned William while he worked, literally putting drinks and bits of food into his mouth . . . [like] a mother bird feeding a demented nestling.” How the mirror polisher dealt with the call of nature during these marathon sessions can only be imagined.
The size of Herschel’s telescopes increased with his growing skill and his need to reach farther into the night’s darkness. His first was a 6-inch device, which he housed in a 5-foot tube of polished mahogany. The last, a 48-inch, half-ton brute was built in 1789 within a 40-foot iron tube and manipulated by a 70-foot wooden gantry. Each was mounted on a Dob-like alt/az carriage. He also made a few portable low-power, wide-angle “sweeper” scopes for Caroline, who used them to hunt down comets. Herschel’s instruments were not only large, they were unmatched in quality, and so before long he was filling orders from Europe’s leading astronomers and crowned heads.
Perhaps the most charming talent that Holmes demonstrates in this book is his ability to carry readers back to a simpler time, when so much of the natural world lay open to discovery by dedicated amateurs: new found landscapes, exotic plant and animal species, double stars, distant galaxies, and more. And so we have the image of Herschel perched high up in his gantry at the eyepiece, conducting one of countless slow sweeps along a meridian, from zenith to horizon, shouting down coordinates and magnitudes to Caroline, bundled against the cold, who sits far below with a shielded lantern, her notebook, and a tireless hand.
For them, and for us, this was an Age of Wonder.
John Herschel carried on his father’s work, cataloging the southern skies from Cape Town. In late 1840, he had the now decrepit 40-footer and its gantry dismantled. A gathering of notables assembled inside the discarded tube to toast the great instrument’s passing:
In the Old Telescope’s tube we sit
And the shades of the past around us flit!
His Requiem sing we with shout and din
While the Old Year goes out and the New comes in.
Merrily, merrily let us all sing
And make the Old Telescope rattle and ring!
Note: for a picture of Herschel’s 40-footer, go to http://en.wikipedia.org/wiki/40-foot_telescope
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