418 EFFECT UPON THE COMPASSES. 



sented to me by Her Royal Highness the Prin- 

 cess Victoria, was in this difficulty extremely 

 useful. The intervals of the lozenge needle 

 were, as usual, considerably shorter than those of 

 No. 3., namely, I' 28* \ and, what was of greater 

 consequence in the present interesting case, they 

 were quite regular in two several trials, and in 

 both the needle returned to its zero without 

 the slightest deviation. One remark I feel it 

 my duty, as an observer, to make, though it 

 may possibly be unfounded. On two occasions, 

 that is, at Rock Rapid and here, No. 3. seemed 

 to be affected, — in the one case by the ac- 

 cidental scraping out of a kettle while it was 

 swinging, at a distance of one hundred and fifty 

 yards; and in the second case by the simple 

 scraping out of a keg. Whether the vibration 

 produced thereby in the atmosphere was the oc- 

 casion of this, I shall not take upon me to deter- 

 mine ; but on all occasions I found it necessary, 

 in order to prevent a swagging motion in the 

 needle opposed to the rotatory one, to hold my 

 hand before my mouth, so that my breath might 

 not fall on the instrument. 



No change occurred in the ice throughout 

 the day, nor was there any alteration calculated 

 to diminish the annoyance of being thus vex- 

 atiously detained at a time when every minute 

 had a compound value ; and to our personal 



