Meteorology of Melbourne. 



165 



made, the inferences which appear to be deduceable from 

 them, and particularly in regard to the nature of the hot 

 winds. 



Referring to the journal which I have kept since the 1st 

 of December, I must first briefly advert to the thermo- 

 metric observations. It will be seen that the highest point 

 reached by the thermometer has been 112^^, in the shade, and 

 the lowest 45 in the night. There has been no night on 

 which the thermometer has not sunk to 74^. We have 

 therefore had none of those very hot or very cold nights, such 

 as are not uncommon in the summers of South Australia :— • 

 and the heat, though on some occasions very intense, has in 

 no instance been very continuous. 



The mean monthly temperature has been estimated in two 

 different ways : — First, by averaging the sum of the daily 

 highest and lowest readings of a Sike's thermometer. Se- 

 condly, by exposing to the air in the shade a copper vessel, 

 containing ten gallons or more of water, closely covered to 

 prevent evaporation, and taking the temperature of this 

 water twice a day, viz. at 6 a.m. and 6 p.m. The results^ of 

 these two methods of observation have been found during 

 December and January to correspond within a sin2;le degree. 

 The mean temperature of December was 68'', and that of 

 January 70^, and that of February 69^^, and of March 68^ ; 

 being ten degrees above the mean of the corresponding 

 summer months in London in 3 844. On the two days when 

 the thermometer stood about an hour after noon at the 

 highest point, 112^ ; viz., on the 28th and 29th January, it 

 sunk in the course of the night to 66^^ and 66*^; thus 

 showing a range of 46^ during the twenty-four hours. 



My observations on the barometer have not been suf- 

 ficiently complete to admit of calculating with precision its 

 mean height. I have recorded the reading of the barometer 

 every day about noon ; and during changes of weather, I 

 have observed it at all hours; but not at other times. 

 Approximatively, the reading was for December, 29-82; 

 January, 29*88 ; February, 30-0, ^ 



The hygrometrlc observations are of more immediate m- 

 terest and practical importance. They have been made 

 principally with a Mason's hygrometer, the accuracy and 

 convenience of which is now generally admitted. It appears 

 that the mean dew point of December was 50*0 ; that of 

 January, 49'5 ; and that of February, 50-3; having thus 

 been practically the same during the three months. I have 



