503 



of temperature in summer, the main difference being that in the morning the wind force continues to 

 decrease for some hours after the temperature lias begun to rise, and that similarly a slight lag is shown in 

 the commencement of the decrease in force in the afternoon, the maximum of temperature occurring at 

 2 p.m. anil that of wind force at 1 p.m. 



As might have been expected, the smoothed winter curve of diurnal variation shows a much smaller 

 range of velocity, amounting to only !! miles per hour The minimum occurs in the morning, as in 

 summer, but two hours earlier, and from 5 a.m., when the velocity is lowest, until the maximum is reached 

 at 9 p.m. the velocity increases in a series of slight undulations, having maxima at 8 a.m., noon, 5 p.m., 

 and p.m., and minima at 10 a.m., 2 p.m., 7 p.m., and at midnight. 



Only three months' observations are available fur the autumn curve, the instrument not having been 

 started until April, 1902. The maximum force occurs at 1 a.m., and not very much variation in shown 

 throughout the day, except that in the forenoon there is an abrupt fall froni eleven and a half miles per 

 hour at 8 a.m. to the minimum of the day at 10 a.m., followed in the next two hours by an equally abrupt 

 rise to about the average force at noon; other slight minima are also indicated at 3 p.m. and 11 p.m., but, 

 if we omit the large decrease in the forenoon, the total amount of the oscillation is less than 2 miles per 

 hour. 



The diurnal range is greatest during the spring months, but, with the exception of that feature, the 

 curves for the two years are very little alike. The combined curve indicates a fairly uniform simple 

 oscillation from a minimum at midnight to a maximum between noon and 2 p.m., small secondary minima 

 being shown at 6 a.m. and 9 a.m., and at 4 p.m. and 9 p.m. 



Wind force is, however, so variable an element that care is required not to attach undue weight to the 

 evidence of so limited a series of observations, and whilst we may perhaps safely accept the broader 

 features of the curves of diurnal variation the smaller oscillations can only be accepted with reserve. 



GALES. 



Defining a " gale " as a wind of at least force 8 on Beaufort's scale, or one in which it attains a mean 

 velocity of at least 38 statute miles per hour, the number of such gales which occurred during the 

 " Discovery's " stay in Winter Quarters was not remarkably large. 



The frequency of their occurrence as compared with that of more moderate winds may be shown by 

 the percentage of the total number of observations of gale force in each month to the total number of 

 observations in the month ; the figures are as follows : 



From this summary it would appear that most of the gales occur in the autumn or winter months, but 

 at the same time it is noteworthy that July and October are the only months for which there are gales in 

 both years. 



These figures, however, do not indicate the number of distinct gales which occurred, regarding each gale 

 as a separate phenomenon lasting for a longer or shorter period. The number of gales, during any part 

 ut which a velocity of at least 38 miles per hour WHS recorded by the cup anemometer was only eleven; 

 but the number of distinct gales, in the course of which an estimated force of 8 or above by Beaufort's 

 scale was logged, was much larger, as follows : 



