108 Meteorology of Bombay, by Colonel Sabine, [No. 81. 



and one mininum, the epochs of which should nearly coincide with those 

 of the maximum and minimum of temperature. 



That exceptions should be found to this state of things in particular 

 localities in the temperate zone, was far from being improbable : it could 

 not be expected that the influences of temperature should always be so 

 simple and direct as they appeared to be at Toronto ; and a more complex 

 aspect of the phenomena might particularly be looked for where a jux- 

 taposition should exist of columns of air resting on surfaces differently 

 affected by heat (as those of land and sea) and possessing different re- 

 taining and radiating properties. In such localities within the tropics 

 the well-known regular occurrence of land and sea-breezes for many 

 months of the year made it obvious that a double progression in the 

 diurnal variation of the force of the wind must exist, and rendered it 

 highly probable that a double progression of gaseous pressure would 

 also be found. 



It was therefore with great pleasure that I received through the kind- 

 ness of a Dr. Buist a copy of the monthly abstracts of the two-hourly 

 meteorological observations made under that gentleman's superinten- 

 dence at the Observatory at Bombay in the year 1843, accompanied by a 

 copy of his meteorological report for that year, possessing a particular 

 value in the full account which it gives of the periodical variations of the 

 wind, and in the explanation which is thereby afforded of the diurnal 

 variation of the gaseous pressure at Bombay, which presents an aspect 

 at first sight more complex than do the three above-named stations in the 

 temperate zone, but which I believe to be equally traceable to variations 

 of the temperature. 



Table I.— Bombay, 1843. Mean temperature, mean barometric pressure, mean 

 tension of vapour, and mean gaseous pressure, at every second hour. 



Hours of Mean Bombay 

 Time, Astronomical 

 Reckoning. 



Tempera- 

 ture. 



Barometer. 



Tension of 

 Vapour. 



Gaseous 

 Pressure. 





deg. 



inch. 



inch. 



inch. 



18 



78-4* 



29-805 



0-750* 



29-055 



20 



79 6 



29-840 



0-766 



> 29-074 



22 



818 



29-852f 



0-771 



29-081f 



0 



83-2 



29-817 



0-768 



29-049 



2 



84- If 



29-776 



0-795 



28-981 



4 



839 



29-755* 



0-800 



28.955* 



6 



82-3 



29-774 



0-802f 



28-972 



8 



81-2 



29-806 



0801 



29-005 



10 



80-3 



29-825f 



0-780 



29-045f 



12 



79-8 



29-809 



0-775 



29-034 



14 



79-4 



29-786 



0-766 



29-020 



16 



789 



29-778* 



0-761 



29-017* 



Mean of the \ 

 Year . . j 



81-1 



29-802 



0-780 



29-022 



• signifies' minimum,' + signifies ' maximum.' 



