of correcting the Local Attraction of Vessels. 285 



ings were taken, and the mean adopted as the correct one (the 

 difference being always very inconsiderable), the master of the 

 ship taking at the same time the bearing of the ship's head by 

 an azimuth compass ; the flag was then hauled down on board 

 and immediately repeated on shore. 



As soon as the ship had been warped quite round the com- 

 pass, we went on shore with the plate ; and on comparing our 

 several bearings, we found that it was at south 4° east that 

 they coincided nearly ; this then was the point in which the 

 iron of the ship had no influence on the magnetic needle, or 

 the line of no attraction. We now proceeded to apply the 

 correcting plate to the compass, trying to obtain its right posi- 

 tion, viz. its distance from the compass and its depth below the 

 pivot of the needle, which was ascertained and measured. We 

 then returned to the ship, and in order to have a proof of the 

 exactness of the results of our experiments, we took with the 

 plate compass the bearing of the object on shore we formerly 

 had observed without the plate, and found it to be correct 

 within a quarter of a degree. 



The Minister has now ordered the same observation to be 

 made on board the ship that is to sail to the South Seas, com- 

 manded by Captain Doxturoff, one of our best officers in the 

 navy, who will on his arrival in England provide himself with 

 one of Gilbert's compasses and a plate, and he will not fail to 

 communicate to you the results of his experiments as soon as 

 they are made, but the ships are not yet in the Roads. 



As these are the first experiments of the kind made here 

 they may be liable to some imperfections, which however will 

 soon be got over. 



Before I conclude this letter permit me to return you my 

 best thanks for your letter of the 7th of February, accompanied 

 by your directions for using the plate, of which I sent a copy 

 to Admiral Greig without delay, who takes a great interest in 

 your valuable discovery, and will not fail to have those expe- 

 riments repeated as soon as he gets one of the plates. 



I have the honour to be, 



With high esteem and regard, 



Yours, very truly, 



(Signed) Krusenstern. 



Experiments 



