124 On the Sea and Land Rates of Chronometers* 



sing contrivances to remedy an evil which has no practical existence 

 where the common discretion of life is exercised in obtaining the bet- 

 ter article at an equal price. 



" Had the especial purpose of the Heela's voyage been to inquire 

 whether the iron of a ship, in its ordinary distribution, would, under 

 extreme circumstances, exert a sensible influence on the chronome- 

 ter, better adapted arrangements could scarcely have been devised 

 for the experiment, nor could a more decisive result in the negative 

 have been obtained. 



" The Hecla was stationary and immovable, being, frozen up, for 

 more than ten months in the vicinity of the magnetic pole, the dip 

 being between eighty eight and eighty nine degrees : such is the sit- 

 uation, and such the circumstances, which are supposed to be best 

 adapted for the developement of magnetism in the stancheons, and 

 other vertical iron of a ship. The chronometers were kept on board 

 the whole winter, and their rates, preparatory to the polar navigation 

 of the following summer, were assigned from the average of the four 

 months immediately preceding her extrication from the ice, at an 

 equal period of four months of navigation. The Hecla arrived at 

 Leith, having experienced much bad weather in crossing the Atlan- 

 tic but on comparing the four chronometers at the Observatory at 

 Leith, their Greenwich time, employing the winter harbor rates, 

 proved less than two seconds in error. 



M On the arrival of the Hecla in the Thames, the chronometers 

 were returned to Messrs. P. and F.'s house in London, when, after 

 a month's interval, they were found to be still going at the same rate 

 as in the Hecla whilst in the harbor of Melville Island." 



Attention was first, we believe, drawn formally to the supposed al- 

 teration of the rates of chronometers on their removal on ship board 

 by the Rev. Mr. Fisher, who found that the rates of those in his 

 charge were uniformly accelerated under such circumstances; and 

 he assigned as the cause, the magnetic effect of the iron, to which 

 Captain Sabine, in the above has so pointedly adverted. 



Many persons well acquainted with the subject were of opinion 

 at the time of the publication of Mr. Fisher's memoir, that from the 

 obvious inferiority of the chronometers which he used, no authori- 

 tative inference could be drawn from any anomalies which their 

 rates might exhibit, — an opinion in which we fully concur. 



One of these chronometers had a rate on board of 3 7 4 /7/ ; but, on 

 its removal to the Observatory, its rate was found to be 18" 2'"; and 



