34 REPORT OF THE SECRETARY. 



were several times ascertained by immersion in buckets of ice- water, 

 and by comparison among themselves in the air, at very low tempera- 

 tures. From all the records of these observations a table of correc- 

 tions was made out by taking the mean of the temperatures as indi- 

 cated by the several thermometers. The result was found to indicate 

 temperatures nearly corresponding Avith those given by standard No. 

 3, wliich had been previously selected as the most trustworthy of the 

 series of instruments. All omissions in the records were supplied by 

 the known methods of interpolation. 



The first results obtained are those which relate to the annual fluc- 

 tuations of temperature. From these it appears that the warmest 

 day was the 15th of July, with a temperature of 41°. G Fahr., and the 

 coldest the 16th of February, with a temperature of — 28°. 



The mean annual temperature falls on the 22d of April and the 

 14th of November, and is -|-G°.OG. It must be observed that this 

 difference in the temperature of the two localities, as we have said 

 before, is due to the open water, and reached its maximum on the 

 20th of March, 18G1, when the thermometer stood 46^ degrees lower 

 at Rensselaer harbor than at Port Foulke. 



The diurnal fluctuation — that is, the difference between the warm- 

 est and coldest hour of the day — exhibits also a remarkable accordance 

 at the two places, its amount being 3°. 38 at Port Foulke and 3°.G4 at 

 the harbor. At Port Kennedy it is 4°. 12. In the month of December 

 the diurnal variation almost vanishes, there being a difference of only 

 two-tenths of a degree between the highest and lowest hour of the 

 twenty-four. It attains its maximum value in March, when it is 8°. 9. 

 The fact. that this greatest effect of the day influence of the suu 

 takes place in March, Mr. Schott is disposed to attribute to the great 

 amount of vapor which formed at a later period and obscured the di- 

 rect action of the sun. On the average for the whole year the tem- 

 perature rises until 2-| p. m. and falls till 2^ a. nl., and the average tem- 

 perature of the day is reached at 8 o'clock morning and evening. 



The dependence of the temperature on the phases of the moon was 

 also attempted to be deduced, but the situation of Port Foulke rela- 

 tive to the disturbing influence of the open water of Smith's straits 

 rendered the result unsatisfactory. 



The relation of the temperature to the direction of the wind was 

 next studied, and it was found that the northeast and east winds, or 

 those which flow over Greenland, are the coldest, while those from the 

 south, southeast, and southwest, or those which pass over ocean 

 surfaces, are the warmer. The northeast wind always depresses, 



