622 METEOROLOGICAL OBSERVATIONS. 



— 52° for 3 J days. For 14 hours it continued between — 58° 

 and — 62-5°. Yet with these low temperatures Sir Edward says 

 " We leave our warm cabins at 50° and rush .after science or 

 bruin " with a change of temperature of about 99° F. " without 

 damage." 



On referring to Vol. II., p. 100, it is seen that the low tempera- 

 tures of — 55° and — 57° were much more keenly felt during the 

 second winter, thus illustrating what has been remarked at Moscow, 

 that English residents scarcely notice the cold during the first 

 winter, but during the second they feel it much more acutely. 



Sir James Ross is said to have registered — 60° F., and on the 

 loth of February 1820 the thermometer stood at — 54° for 15J 

 hours (Belcher, 1. p. 202). 



The mercurial thermometers were observed to register correctly 

 below the temperature — 39-5° F., and towards the end special 

 attention was given to this, and the comparison with the standard 

 spirit thermometer showed that down to — 46° the mercurial 

 thermometers rise and fall with the spirit thermometer very 

 regularly. 



Experiments on the freezing of mercury showed that exposed 

 for 20 minutes to a temperature of — 47*7° the mercury began to 

 crystallize, the circumference became very convex at the edges of 

 contact with the conical vessel in which it was contained, and the 

 centre raised to a point when it had actually congealed. When 

 placed solid into water at —47*5° the mercury became encased in 

 ice, but flowed on the bottom at a temperature of — 44-5°F. Pre- 

 vious to freezing, or at the instant of returning to fluidity, the 

 mercury assumed a very active motion, resembling lively polypi, 

 parts moving in circles with great velocity. An attempt was made 

 to determine the form of crystallization (p. 208). AUsopp's ale 

 was found to freeze at 22*5° ; the frozen part was found to be very 

 insipid, the remainder concentrated forming an excellent liqueur. 



Note. — McClintock froze AUsopp's ale when the temperature 

 of the air was —35°. When its temperature had risen to 17° it was 

 almost all thawed, at 22° it was completely so. 



P. 209. In describing experiments on the expansion of alcohol 

 at low temperatures a very useful caution is given, the neglect of 

 which may be very serious, to take care of the fingers in handling 

 good conductors or good absorbers of heat at low temperatures. 



During the early part of March 1853, the temperature still con- 

 tinued low, the mean on some days being as low as — 46°, — 52*8°, 

 — 52°, and the mean of 10 days being - 43-23° F. After the 

 17th of March a most decided change took place in the weather. 



The hole for the tide-gauge was cleared, the ice being 7 feet 

 thick, and the v/hole thickness of ice and snow was 21 feet within 

 20 yards of the ship. The ice towards the shore grounds in 16 

 feet of water, the thickness of off-shore floe formed in one season 

 probably does not exceed six feet in thickness. As soon as the 

 hole under the stern for the tide-gauge had been completed, the 

 water rushed up similar to an artesian spring; this is singular 

 since the fire-hole abreast of the ship had been kept open all the 

 winter. 



