680 



creasing heat of the day*. The first horary- 

 observations having been made only near the 

 coast, Mr. Playfair, whose extensive knowledge 

 and superior abilities have never been contested, 

 believed for a long time-}- that the atmospheric 

 tides observed in the equinoxial zone, were 

 owing to the alternating winds from land and 

 sea. The periodical regularity of those tides may 

 now be regarded as one of the physical pheno- 

 mena that are best known and most universally 

 verified. It has been ascertained at the same 

 time in the vast extent of the Ocean, and in 

 the interior of the land ; in plains, and at two 

 thousand toises of height ; between the tropics, 

 and in the temperate zones of the two hemi- 

 spheres. Before I mention the results that 

 may be drawn from the numerous observations 

 comprised in the preceding tables, I shall relate 

 succinctly and in chronological order, the va- 

 rious attempts of naturalists to verify the regu- 

 larity of the horary variations of the barometer. 



* Cotte, Traite de Mdtorologie, 1774, p. 344. The author 

 did not recollect that the minima of the pressure correspond 

 at the same time with the hottest and coldest hours of night 

 and day. 



f Edinb. Trans., Vol. v, pi. iii, p. 6. The same cause was 

 indicated later by captain Flinders, whose long and myste- 

 rious detention was deplored by all the friends of justice, hu- 

 manity, and the sciences. (Tuckey, Marit. Geogr., Vol. i, p. 

 525.) 



