24)2 Second Report of the Meteorological Comimttee of 



The observations of Mr McHardy, though extending only to 

 latitudes south of the equator, and, though evidently made with 

 far less care, and with an instrument in which the fluctuations 

 arising from the motion of the ship are very imperfectly de- 

 stroyed, yet, when reduced and grouped in a similar manner, 

 afford a result agreeing in their general tenor very satisfactorily 

 with those of Sir E. Ryan. To render them comparable, as the 

 zero of Mr M^Hardy's barometer is unknown, a correction of 

 — 0.188 has been apphed to all his reduced observations, by 

 which the equatorial indications of the two barometers are made 

 to agree, and the following Table exhibits their results when so 

 reduced, grouped, and corrected : — 



The total depression concluded from the latter series of ob- 

 servations agrees very nearly in amount with that stated by Sir 

 J. Herschel, as the result of his own observations during his 

 voyage from England. The general fact may now therefore 

 be looked upon as unequivocally established, and it is hoped 

 that it will henceforth attract the attention of all voyagers; and 

 that observations will be diligently accumulated for the pur- 

 pose of ascertaining the law of variation of atmospheric pres- 

 sure in all latitudes both within and beyond the tropics, and in 

 either hemisphere, since it is very possible that the same exact 

 law may not be found to apply to both, and that the Atlantic, 

 Indian, and Pacific Oceans may offer differences depending on 



