Oa, the Constant Currents in the Air and in the Sea. 97 

 what similar forms. Suppose 



or 



(e* D * + !)/(#) =0. 

 The roots of the equation e XD * -f- 1 = are 



D + W^T 



where i is any odd integer. Hence 



/(a?) = 2 A^cos^- 



t=i A, 



+ 2, B^sm-r— * 



x=l A. 



where i is an odd integer. 



Several other theorems of a similar nature will readily sug- 

 gest themselves as capable of similar treatment. 



1 1 Elysium Row, Calcutta. 



XV. The Constant Currents in the Air and in the Sea : an At- 

 tempt to refer them to a common Cause. By Baron N. Schil • 

 ling, Captain in the Imperial Russian Navy. 



[Continued from p. 38.] 



B. Rotation of the Earth on its Axis. 



IN the daily motion of the earth on its axis, every point of the 

 surface describes a circle. These parallel circles become, 

 smaller and smaller from the equator to the pole. Now, as all 

 points of the surface describe their circles in one and the same 

 time of nearly 24 hours, it is evident that as the poles are ap- 

 proached the velocity of motion of the points diminishes, and 

 this in the ratio of the cosines of the latitudes. As already men- 

 tioned in discussing Hadley's theory of the trade-winds, a body 

 approaching the equator, continually coming into circles of 

 greater velocity, will, in consequence of the law of inertia, have 

 the tendency to perform its revolution more slowly than these ; 

 and hence the direction of motion of that body will undergo a 

 westerly deflection. Conversely, a body moving from the equator 

 will be continually meeting with parallel circles of less and less 

 velocity, and hence will take a direction swerving eastwards. 

 Since the commencement of the 18th century the correctness of 

 this law has been admitted, and it has been made use of to ex- 

 plain the direction of the trade-winds and many other pheno- 

 mena. The Academician von Baer, for example, ascribes it to 

 Phil. Mag. S. 4. Vol. 48. No. 316. Aug. 1874. H 



