1875 CHRONOMETERS. 77 



essential in Arctic navigation. She, as well as the 

 " Alert,' ran not a few hairbreadth escapes. Once m 

 particular when in following us through a closing chan- 

 nel between an iceberg and heavy floe-piece, before 

 getting quite past the danger she was caught and 

 nipped against the berg, fortunately without suffering 

 severely. 



Having less beam than the ' Alert,' a finer bow and 

 an overhanging stem, the ' Discovery ' proved to be best 

 adapted for forcing her way through the pack. Being 

 backed some distance astern to allow space for the 

 debris ice from a former blow to float away, and for 

 the vessel to attain sufficient distance for the accumu- 

 lation of momentum with which to strike a second, 

 when forced ahead at her utmost speed she would 

 break her way into the ice for a distance of about 

 twenty feet before the force of the blow was expended. 

 We found that lloes up to four feet in thickness and in 

 a soft state, melting not freezing, might be charged 

 with impunity ; thicker or harder ice had to be left 

 alone. 



It speaks well for our chronometers, and the 

 manner in which they were secured, that their rates 

 were little affected by the frequent concussions on this 

 and on many after occasions. 



It must be obvious that the commander of an 

 Arctic expedition can obtain but little rest during the 

 navigable season. In ice-navigation one false decision 

 may imperil the chance of farther advance, he there- 

 fore can depute his responsibility to no one, but must 

 be constantly on watch himself. Fortunately for his 

 health an Arctic season lasts only for from three to 

 six weeks. 



