Triumphs and wonders of the 19th century, the true mirror of a phenomenal era, a volume of original, entertaining and instructive historic and descriptive writings, showing the many and marvellous achievements which distinguish an hundred years of material, intellectual, social and moral progress .. . on record. Bowditchs accuracy has passed into a proverb. Hegave the latitude of all the principal seaports of the world with marked pre-cision ; while some of the longitudes are now found to be slightly in error, itis surprising that his determinations of those of Boston and Philadelphiashould be
Triumphs and wonders of the 19th century, the true mirror of a phenomenal era, a volume of original, entertaining and instructive historic and descriptive writings, showing the many and marvellous achievements which distinguish an hundred years of material, intellectual, social and moral progress .. . on record. Bowditchs accuracy has passed into a proverb. Hegave the latitude of all the principal seaports of the world with marked pre-cision ; while some of the longitudes are now found to be slightly in error, itis surprising that his determinations of those of Boston and Philadelphiashould be exactly the same as those obtained by the best methods in useto-day. But he makes San Francisco and Halifax seven miles too far to theeast, and New York eight miles too far west. But we are to remember thatfor this computation the best available instruments were the chronometersof a century ago, and that lunar observations were made with the ..Id-timesextant. 100 TRIUMPHS AND WONDERS OF THE XIXth CENTURY As applied to geodesy, astronomy has added a process of ascertaining geo-graphical latitude with marvelous accuracy and speed by the use of thezenith telescope, an instrument devised by Major Talcott in 1835. Thisinstrument cair be set in a vertical direction with ease, and be pointed alter-. ZENITII TELESCOPE. Made for University of Pennsylvania by Warner & Swasey. nately to two stars that cross the meridian at a brief interval of time, the onenorth and the other south of the zenith. Difficulties that arise from refrac-tion are avoided, and the resulting latitude is quickly computed. Thismethod is largely employed in the surveys of the public lands, as also inestablishing the boundary between the United States and British America, ASTRONOMY DURING THE CENTURY 101 XIV. NOTABLE EPOCHS IX THE NINETEENTH CENTURY. Worth marking as epochs of the nineteenth century were such dates asOctober 10, 1846, when the first determination of difference of longitude oitwo places was made by th
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