180 VOYAGE TO THE POL.AR SEA. October 



an extremely difficult matter at any time ; in the Arctic 

 regions, where the inside temperature of the ship 

 differs from fifty to over a hundred degrees from 

 that of the outside air, the difficulty is considerably 

 increased. Every precaution has to be taken to pre- 

 vent the cold descending air mixing directly with the 

 warm and rarefied atmosphere of the mess-deck ; for 

 wherever this takes place the air becomes vaporized 

 and the moisture is deposited. To effectually warm 

 the fresh air would consume more coal than an Arctic 

 ship could possibly carry. If the question were one of 

 ventilation alone no difficulty would be experienced ; 

 for with a difference of temperature of fifty degrees 

 the down rush of fresh air is so strong that the supply 

 has to be regulated. 



Sir Edward Parry, after his third and last voyage 

 to the Arctic seas, observes : — 



6 No means for the production of internal warmth 

 will prove sufficient, without the most minute attention 

 to the stopping of every crevice communicating w T ith 

 the external air. There should, on this account, be no 

 openings whatever, but those for the stove pipes and 

 the two ladders. ... I have heard a doubt expressed 

 whether, with all these precautions, there is not a risk of 

 not admitting enough fresh air for healthy respiration 

 and to afford draught to the fires. But I do not think 

 there is any apprehension : enough, and, without great 

 care, more than enough, for these purposes will always 

 gain admission by the frequent opening of the doors ; for 

 it should be remembered that the more warmth is pro- 

 duced below, the more forcibly will the cold air from 

 above find its way in to supply the place of that which 

 is rarefied.' 



