Maxima and certain Conditions of Temperature, §c. 417 



each hour from 6 a.m. to noon in each half of the year. But it is 

 sufficient to explain the early occurrence of its maximum. 



Hourly Change of the Forenoon Temperature at Bombay. 



Hour 6 to 7 7 to 8 8 to 9 



April to September.. +0'9 + T2 +1*1 deg. Fahr. 

 October to March .. +0 5 +21 +T9 „ 



Hour 9 to 10 10 to 11 11 to noon 



April to September. . +0"9 +0*8 + 07 deg. Fahr. 

 October to March .. +1'8 +17 +17 „ 



At Calcutta, Batavia, and Melbourne, the observatories are 

 sufficiently far from the sea to exclude the supposition that they are 

 subject to its influence in anything like the same degree as Bombay, 

 but at all of these the temperature must be influenced by convection, 

 which is most active in the summer months ; and, as already 

 remarked, it is at this season that the instant of most rapid heating 

 precedes the barometric maximum by the longest interval. In 

 certain of the winter months, viz., August at Batavia, and May and 

 July at Melbourne, the time of most rapid heating, aDd that of the 

 barometric maximum are as nearly coincident as at Prague and 

 Yarkand ; and in June, at Melbourne, the latter appears to anticipate 

 the former by about half an hour. Of this opposite anomaly I am 

 not prepared with any explanation. More than one circumstance 

 might be imagined in the local conditions of the observatory which 

 would retard the instant of greatest rise, but without searching- 

 inquiry and examination on the spot, any suggestion would be mere 

 vain surmise. I may, however, notice that the June curve of 

 temperature departs from the ordinary parabolic form in a manner 

 that points to the existence of some local irregularity, and that similar 

 irregularities are noticeable in other parts of some others of the 

 monthly curves. 



As a final conclusion, if these data, when subjected to the rigorous 

 test I have applied, do not give strong support to the hypothesis, 

 neither do they, with the single exception just mentioned, show any 

 discrepancy which is not susceptible of a simple and probable 

 explanation ; and the single exception is one which might also 

 probably be explained, were the requisite information available. 



Evening Maximum. 



The tendency of the skies to clear after sunset in settled weather 

 has been noticed by many writers, even in the irregularly variable 

 climates of Europe, and in India it is most striking at all seasons of 

 the year. The cloud registers of nearly all stations at which hourly 

 observations have been made, show a strongly marked minimum 



