Hstronomg in tbe Hrcttc m 



observation of the comet was, I take it, named after 

 Lieut. Bellot, the French explorer. It was shortly after 

 reading the adventures of the Fox that I stood near 

 the monument erected to the Lieutenant's memory, 

 in front of the Royal Naval Hospital at Greenwich. 



ii 



Under date January 26th, 1859, Admiral M'Clintock 

 remarks that part of the sun's disk loomed above the 

 horizon " somewhat swollen and disfigured by the 

 misty atmosphere," and he tells how he halted to 

 feast his eyes upon the glorious sight, and to scan the 

 features of their returning friend after an absence of 

 73 days. He adds : " On looking over the records of 

 previous voyages, I find that the average amount of 

 refraction upon the horizon is about 45 minutes of arc, 

 the temperature being 35 degrees below zero. Last 

 year, when the sun reappeared, on January 28th, 

 there was 59 minutes of refraction, and the tempera- 

 ture at the time was 38 degrees below zero." 



In regard to this instructive example of polar re- 

 fraction, I might say that at the horizon in temperate 

 latitudes, refraction appears to be on the average 

 34 minutes 54 seconds ; but, of course, it is necessary 

 that the thermometer and the barometer should both 

 be read. It has been ascertained that refraction is 

 increased by a low thermometer and a high barometer, 

 which will explain the large amount of it observed 

 by Admiral M'Clintock with the temperature so far 

 below zero. Those extraordinary shapes assumed by 

 the sun near the horizon are due to refraction, though 

 I cannot say that I have observed the moon to display 



