178 THE CHEMISTRY OF CREATION. 



A phenomenon yet more extraordinary is 

 that of Atmospheric Waves. As yet the dis- 

 coveries made on this singular subject are very 

 incomplete ; but Mr. Birt, who has made them 

 his peculiar study, is zealously engaged in 

 prosecuting the research. It cannot now be 

 doubted, that though invisible to us, there 

 occur, at certain periods of the year, phe- 

 nomena in the atmosphere, which are clearly 

 analogous to waves. Not mere undulations of 

 a slight extent, like those of the surface of the 

 sea, but great wave-like movements, pervading 

 the whole depth of the atmosphere, and occu- 

 pying several days in their duration. The most 

 remarkable of these is a vast wave, which has for 

 several years been observed about the middle 

 of the month of November. It lasts, with some 

 modifications, for about sixteen days ; that is, it 

 begins, rises higher and higher, until it reaches 

 its highest point; then subsides again, and the 

 atmosphere returns to its usual condition, in 

 the space of a fortnight, or sixteen days. Some- 

 times it has been observed to set in with a gale 

 of wind, and to end with one also. We are 

 not yet in full possession of a sufficient number 

 of facts to enable us to determine its cause or 

 causes, with accuracy. 



It has been remarked, as a curious coincidence, 

 that the period at which this great November 



