384 Second Report of the Meteorological Committee 



Heuschel, with the Mural Circle Barometer of the Cape 

 Observatory, the difference of which from the Standard of the 

 Royal Society had been previously ascertained by two distinct 

 comparisons agreeing perfectly inter ss made by the inter- 

 vention of the above-mentioned portable Barometer, which had 

 been brought to the Cape by Mr. Hendersok, and again 

 transported by him to London. By these comparisons it was 

 found that Sir E. Ryan's Barometer required a correction of 

 — 0.116 in. to reduce it to the Royal Society's Standard. 

 This correction being applied, and the reading so corrected 

 being reduced to the freezing temperature, and classed into 

 groupes in zones of 10° in breadth, proceeding Northwards 

 ^nd Southwards from the Equatorial Zone (between the Lati- 

 tudes 5° N. and 5° S.) according to the observed latitudes 

 of the ship at noon of each day, give as follows : — 



The observations of Mr. MacHardy, though extending 

 only to Latitudes South of the Equator, and though evidently 

 made with far less care and with aji instrument in which the 

 fluctuations arishig from the motion of the shi-p are ypry 

 imperfex:tly destroyed, yet, when reduced and grouped in a 

 similar manner, afford a result agreeing in their general tenor 

 very satisfactorily with those of Sir E. Rvan. To render them 

 comparable, as tlie zero of Mr. MacIIaudy's Barometer is 

 unknown, a correction of —0 . 188 has been applied 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 

 observations agrees very nearly in amount witli that stated by 

 ,Sir J. Heuschel, as the result of his own observations during 



The general fact may now tljcreforj? 



liis voyage from England 



