THE BEGINNING OF MODERN NAVIGATION: EXCEPTIONALLY RARE AND IMPORTANT 1761 PARLIAMENTARY ACT ENCOURAGING THE PUBLICATION OF DETAILS ON A NEW DEVICE MEASURING LONGITUDE AND PROMISING INVENTOR JOHN HARRISON THE SOLE REWARD IN THE EVENT OF ITS SUCCESS

HARRISON, John. Anno Tertio Georgii III. Regis. Cap. XVI. An Act for the Encouragement of John Harrison, to Publish and Make Known His Invention of a Machine or Watch, for the Discovery of the Longitude at Sea. FROM: Anno Regni Georgii III… At the Parliament Begun and Holden at Westminster, the Nineteenth Day of May, Anno Dom. 1761, in the First Year of the Reign of Our Sovereign Lord George the Third… And from Thence Continued by Several Prorogations to the Twenty Fifth Day of November, 1762; Being the Second Session of the Twelfth Parliament of Great Britain, pp. 359-63. London: Printed by Mark Baskett, 1763. Folio (8 by 13 inches), period-style full sprinkled calf, elaborately gilt-decorated spine and boards, raised bands, red morocco spine label, marbled endpapers; pp. 4.

First edition of the 18th-century parliamentary act encouraging publication of the details of any mechanical machines allowing for the discovery of longitude at sea and limiting financial rewards to inventor John Harrison. Beautifully bound.

When Columbus sailed to America, he followed almost a straight line westward, marking his latitude by observations of the sun and the stars. He had no reliable means of determining how far west “the Indies” were from Spain, for to determine longitude, one has to know the exact time on one’s ship and in one’s home port—an impossibility with pendulum clocks because of the effects of weather, waves, and wear. Solving this problem was acutely important during the great age of discovery and for three centuries every major maritime nation energetically sought a solution. In 1714, Parliament offered £20,000, the equivalent of millions today, to anyone who devised a means of accurately determining longitude at sea. John Harrison, a clockmaker without formal education, developed friction-free mechanical clocks that were unaffected by changes in temperature or movement, and which were extremely accurate. The first of Harrison’s devices was successfully tested in 1735 and three other more accurate models were created over the next four decades. Though his device was clearly accurate and sea-worthy, Harrison was awarded only half of the promised prize; this and an act published two years later were the closest Harrison came to official Parliamentary recognition of his singular contribution to navigation and cartography. This copy is from the Sessional Volumes of Parliament, the earliest official printings available. Acts printed prior to 1796 are extremely scarce, since the maximum number printed “only slightly exceeded 1,100 copies,” and those were distributed solely to Members of the Houses of Parliament, the great officers and offices of state, and the judiciary (see Report of the Committee for the Promulgation of the Statutes, 1796).

Text clean and bright. A beautifully bound copy in fine condition.