708 



are remarked, of which the epochas of maxima 

 and minima swerve regularly (more than two 

 hours for instance), from the period of 4h till 

 9 h in the morning, and from 4 h till 10^h in the 

 evening ? The table placed at the end of this 

 memoir will shew that in the only parts of the 

 earth where a sufficient number of observations 

 have been made to furnish with precision the 

 hours when the variations attain the extreme 

 limits, nearly thirty observers have found a 

 striking accordance # in the return of the same 

 epochas. 



Places where it has been often too lightly as- 

 serted that the periodicity of the atmospheric 

 tides is irregular, have been discovered, after 

 mature examination, to present the greatest re- 

 gularity in the epochas of the maxima and the 

 minima. M. d'Eschwege found those epochas 

 precisely similar to those of Cumana, in the low 

 and hot part of Brazil, bounded by the two 

 chains of the Espinhaco and the shore -fy for 

 instance at San Joao Baptista, in the missions 

 of the Caroatos Indians ; while, on the con- 

 trary, at Villarica and Rio Janeiro, the type 



* An excellent observer, Mr. Colebrooke, affirmed very 

 recently, that even in the interior of India, in most places the 

 periodicity is manifest and independent of the variations of 

 the temperature, and the season of the year. Asiat, Res,, 

 Vol. xii, p. 266*. 



+ See above, Vol. vi, p. 531. 



