^60 lloyal Society. 



turnal atmospheric tides, embracing two maxima and two minima in 

 tUe twenty-four hours. The following are the chief topics noticed in 

 the paper, and the principal facts established by these inquiries: 

 namely, I. The removal of the doubts entertained by Humboldt, 

 founded on the authority of Horsburgh, of the suspension of the at- 

 mospheric tides during the monsoon in Western India j the existence 

 of the four atmospheric tides already mentioned, and their occurrence 

 within the same limiting hours as in America and Europe; the greatest 

 mean diurnal oscillations in Dukhun taking place in the coldest 

 months, and the smallest in the damp months ; whilst at Madras, 

 the smallest oscillations are in the hottest months, and in Europe it 

 is supposed that the smallest oscillations are in the coldest months. 

 2. The regular diurnal and nocturnal occurrence of the tides, 

 without a single case of interversion, whatever may be the thermo- 

 metric or hygrometric indications, or the state of the weather ; storms 

 and hurricanes only modifying, but not interrupting them. 3. The 

 anomalous fact of the mean diurnal oscillations being greater at 

 Poona, at an elevation of 1823 feet, than at the level of the sea, in a 

 lower latitude, at Madras. 4. The fact of the diurnal tides, at a 

 higher elevation than Poona, being less, whilst the nocturnal tides 

 are greater than at Poona ; and the seasons apparently not affecting 

 the limiting hours of the tides. 5. The maximum mean pressure 

 of the atmosphere being greatest in December and January ; then 

 gradually diminishing until July and August j and subsequently in- 

 creasing to the coldest months. 6. The very trifling diurnal and 

 annual oscillations compared with those of extra-tropical climates. 

 7- The annual range of the thermometer being less in Dukhun 

 than in Europe, but the diurnal range much greater; the maximum 

 mean temperature occurring in April and May, and gradually de- 

 clining until December and January ; and the observed mean tempe- 

 rature of places on the continent of India being much higher than 

 the calculated mean temperature according to Mayer's formula. 

 8. The mean annual dew-point being higher at half-past nine o'clock 

 than either at sunrise or at four in the afternoon j the dew-point 

 being highest during the monsoons, and lowest during the cold months, 

 and varying considerably within very short distances ; being, for ex- 

 ample, remarkably contrasted in Bombay and Dukhun ; and the fre- 

 quent occurrence of dew quite locally and under anomalous circum- 

 stances. 9. The amount of rain in Dukhun being only 20 per cent, 

 of that falling in Bombay, 90 or 100 miles to the westward. 10. The 

 wind being principally from the west and east, and rarely from the 

 opposite quarters. 1 1 . The great abundance of electricity under cer- 

 tain circumstances. 12. The rare occurrence of fogs. 13. The great 

 amount of solar radiation ; and lastly, the singular opacity of the 

 atmosphere during hot weather, giving rise occasionally to the mirage. 

 A variety of tables containing the records of meteorological obser- 

 vations, with instruments, accompany the paper. 



10. ** On the Ova of the Ornithorhynchus paradoxus^ By Richard 

 Owen, Esq. Communicated by W. Clift, Esq., F.R.S. 



