The Day the World Discovered the Sun Read Online Free PDF Page A

Tobolsk observatory’s latitude was 58 degrees, 12 arc minutes, and 22 arc seconds, give or take an arc second. According to his solar measurement, his latitude was 58 degrees, 12 arc minutes, and 13 arc seconds. Either way he was close but not quite spot-on, 39 arc seconds or about three-quarters of a mile off the actual latitude of Chappe’s observatory site. 20
    Calculating longitude, though, was the real trick. French astronomers typically relied on careful timing of the motions of the planet Jupiter’s moons to find longitude. Noting the exact moment (local time) when any of the four prominent Jovian moons passed behind or emerged from the planet provided an ersatz celestial clock. Nautical almanacs like the Parisian Conaissance des Temps contained predictions of when (Paris time) the Jovian eclipses would take place. An astronomer in the field could then, ideally, look up when (Paris time) the Jovian moon was predicted to disappear and reappear from behind Jupiter. The difference between local time and Paris time for any given Jovian eclipse, then, represented the longitude difference between Paris and the observer’s location.
    However, Chappe also happened into an even better longitude trick: a partial eclipse of the sun passed through the region on June 3. Chappe took down exactly when it began and ended. Ultimately he could use this number to calculate Tobolsk’s longitude down to at least a few arc minutes.
    None of his technical accomplishments meant a whit to anyone around him. Other than the governor and a few of his aides, practically no one in Tobolsk knew what the newcomers were doing on the hilltop near town. None of the hired hands knew what mysterious deeds lie concealed behind the intricate machinery that the strange man fromafar so carefully attended to. All the locals had to judge by was the stranger’s peculiar behavior.
    A contemporary engraving based on a sketch by Chappe’s artistic collaborator Jean-Baptiste Le Prince depicts what was probably a familiar sight at the observatory. In the image, the observatory’s tall wooden front door was swung wide open with a rapturous Chappe peering through the sights of his astronomical quadrant, set squarely in the middle of the barn-like structure’s opening. Through his instrument the Frenchman viewed lightning discharges during a thunderstorm. Meanwhile, local officials and assistants were huddled around the door frame’s edge, as if taking shelter from the possible wrath of God that could be unleashed by such a close and inquisitive inspection of nature’s wonders. 21
    Chappe did most of his instrument calibration during brief stretches at night, training his telescopes on the moon and prominent stars. His living quarters, though, were in town. Some mornings Chappe returned to his bunk in town as the 5:00 AM sunrise colored the awakening city in pink and orange. The philosophe paid little attention to clothes or grooming, not even presenting token efforts to match the ostentatious rank his royal post had given him. Already every bit the foreigner in a foreign town, Chappe recognized the suspicious glances his grizzled appearance cultivated. To everyone but the lofty folks on the hill, Chappe was persona non grata.
    From his group’s translator, he learned that some in town had thought Chappe was a wizard preparing to commune with the skies or some spiritual realm. Some who’d heard about the purpose of Chappe’s observations whispered that the wizard was preparing for the end of the world—which, naturally, would arrive when Venus crossed the solar disk on June 6.
    The storm clouds of spring gathered as the already overflowing Irtysh River hugged Tobolsk. On one fateful spring day, drenching rains and thunder rumbling through the hills gave the French visitors a secondwelcome. Timber crashed to the ground as the Irtysh breached its banks and drowned sections of Tobolsk in floodwater. Refugees