106 On Dove's Law of the 



when properly examined, keeping in mind what was to he in- 

 vestigated, were fonnd to he the strongest pillars whereupon 

 this great law of the household of nature is based. 



In proving the truth of the law of turning, we can pursue 

 a two-fold mode — either we prove it by direct observations, 

 that is, by carefully registering the anemometer, and then 

 examining the "retrograde" and "direct" motions, if we un- 

 derstand by the latter the revolutions in the sense S., E., N., 

 W., S., and under the former these in the sense S., W., N., 

 E., S. ; this being for the southern hemisphere. I have 

 undertaken this task for the year from March 1858 to 

 February 1859, according to the following method. The 

 results are derived from hourly observations, and the regis- 

 trations are noted within one point, or 11 j degrees exactly. 



Eight columns were formed to receive the positive and 

 negative (direct and retrograde) motions of the vane from one 

 hour to the following one. In case the vane passed through 

 more than one point ; the number of points were counted, 

 and if more than four points, distributed on the different 

 sextants through which the vane had passed, and here it 

 was always understood that the vane had accomplished its 

 way by the shorter route, i.e., by less than sixteen points. 

 In case that the vane went from one point of the compass to 

 that diametrically opposite, the registration was not taken 

 into account at all, as it could not be said which way the vane 

 went, and such instances are marked by "jumps." 



The positive and the negative motions have been summed 

 up for each month, each quarter, and for the year, and 

 the difference between the positive and negative number of 

 points was taken as the balance of the one over the other, 

 which, divided by 32, gives the number of whole revolutions 

 in the one sense or the other. 



The following table contains the results from such investi- 

 gations : — 



March, 1858 9*2 positive revolutions. 



April, 1858 4-2 



May, 1858 2"1 



June, 1858 2'6 „ 



July, 1858 3-5 



August, 1858 1-8 „ 



September, 1858 6"2 „ 



October, 1858 1-5 „ 



November, 1858 33 „ 



