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Excerpt from Account of Improvements in Chronometers: Made by Mr. John Sweetman Eiffe; For Which a Reward Was Granted to Him by the Lords Commissioners of the Admiralty IN the winter of 1835, Mr. Eiffe informed me that he had invented arrangements for correcting one of the errors to which the best chronometers are liable (the losing rate at ex treme temperatures, whether of cold or of heat, when the compensation is adjusted so as accurately to counteract the effects of variation of warmth near mean temperature); and he communicated to me (in strict confidence) two constructions which he proposed to use for that purpose. These were the same as those represented respectively in figures I and 2, and in figure 11, of the plates attached to the following account. I had no hesitation in giving my opinion that, whatever unforeseen practical difficulties might be found in the actual introduc tion of those constructions into chronometers, the principle was correct, and admitted of being carried so far as actually to reverse the error, causing the chronometers to gain at extreme temperatures instead of losing, as is the case with all common chronometers; and, therefore, that the adjustment for equalization of rates throughout would become a question of mere manual dexterity. With my consent, therefore, Mr. Bifl'e solicited of the Lords Commissioners of the Admiralty, authority for the trial of two chronometers at the Royal Observatory, with special reference to the steadiness of their rates at extreme temperatures. Accordingly, two chronometers containing Mr. Eiffe's improvements (marked Eifi'e 3 and Eiffe 4) were tried at the Royal Observatory in juxta-position with two good Government chronometers (earnshaw 543 and Earnshaw 819) from 1836, February 27, to June 25. In the colder season, they were exposed to the open air; in the warmer season they were heated by a fire; in the intermediate temperatures they were placed as usual in a room. The circumstances of the season were not favourable for the obtaining of. Extreme temperatures; nevertheless I was fully enabled to express a most favourable opinion on the success of the application of the principle. My Report, addressed to the Lords Commissioners of the Admiralty, is dated 1836, June 29. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.