170 



LIEUT.-COLONEL SYKES ON THE ATMOSPHERIC TIDES 



hibit comparatively a low range, in fact the month of July has the lowest mean di 

 nrnal oscillation in each year; and it may be broadly stated, that with two or three 

 exceptions the monthly mean diurnal oscillation increases from July to December or 

 January, and decreases from these months to July. How far the monthly mean oscil- 

 lations of the barometer and the monthly mean range of the thermometer coincide, 

 will be seen by the following Table. The monthly mean temperature and the monthly 

 mean diurnal oscillations of the barometer have little coincidence. 



Mean range of the Thermometer attached to Englefield's Barometer between sun- 

 rise and 4 — 5 p.m. at Poona and Mahabuleshwur. 



In 1827 the greatest monthly mean diurnal oscillation and the maximum mean range 

 of attached thermometer were coincident in December ; but the next greatest mean 

 oscillation was in November, whilst the greatest mean range was in February. No- 

 vember and March have nearly the same mean thermometric range, but differ 0*196 

 in mean barometric oscillation. In 1828 the greatest mean oscillation and range of 

 thermometer are coincident in February. January accords in a similar manner ; 

 but May is quite anomalous, having a mean barometric oscillation of the monsoon 

 month of September, range of thermometer +5°-88, whilst its own range is -|-19°'82. 

 In 1 829 the movements of the barometer and thermometer are not coincident ; the 

 maximum of the former being in January, that of the latter in February. In Decem- 

 ber we find the oscillation of the barometer nearly identical with that of January 

 preceding, whilst the mean range of the thermometer is nearly seven degrees less. 

 At Mahabuleshwur the monthly mean maximum oscillation of the barometer is in 

 April, whilst the maximum mean range of the thermometer is in February, and 

 nearly doubles the range of April. 



* The observation for those months with the * were taken in Bombay, with the f at Hurreechundurghur, 

 ftnd with + at Chamblee. 



