226 Mr Barlow on the Rates of Chronometers. 



has reported, or whether, as in most instances, the chronome- 

 ters were suffered to go down the moment the expedition re- 

 turned. 



The other case to which I have alluded, I give verbatim 

 from the note I took of it a few years back, while I was at 

 Chatham dock-yard on some business for the Navy Board re- 

 lative to the stowage of the compasses in that establishment. 

 " Mr Duncan, the master attendant of this yard, who appears 

 to have always paid great attention to the compasses, inform- 

 ed me of a remarkable case which happened to him in the 

 year 1791, while he commanded the Beaver, a vessel belong- 

 ing to the Hudson's Bay Company. His object seems to have 

 been to find a north-west passage, and while on this service, 

 on the 18th of August of the above year, in latitude 61° 

 52' north, and longitude 92° 23' west, being then about twenty 

 leagues from land, and with soundings from sixty to sixty-five 

 fathoms, with blue mud, he found his azimuth compass, 

 (which he describes as a very excellent one, by the senior Gil- 

 bert) suddenly affected in a very remarkable way, the needle 

 refusing any fixed direction whatever. He immediately or- 

 dered up his other compasses, seven in number, and they were 

 found to be all affected in the same way, revolving round and 

 round in the most singular manner. He then stood off from 

 the land, and soon after these instruments all resumed their 

 usual action. 11 



" Mr Duncan had with him also a dipping-needle, furnish- 

 ed by the Royal Society, and the dip, on which he also made 

 some observations, varied during a short time from 78° to 86°. v 

 The above particulars were all noted by him immediately, 

 and I extracted them from his log-book. 



Another instance of a very similar kind was reported to Dr 

 Gregory by Mr Edmondston of Unst, one of the Shetland 

 islands. This case is as follows : Dr Gregory, while making 

 his pendulum experiments, having found the results to be dif- 

 ferent from what he had anticipated, suspected that it might 

 arise from some partial terrestrial magnetism, and having 

 mentioned his suspicions to Mr Edmondston, that gentleman 

 informed him, that, in one instance, several of his boats 

 were out fishing, and the weather being foggy, they had re- 



