68 



The same number of observations that I have given might 

 have been completed in a smaller space of time, but un- 

 favourable skies, necessary interruptions, and the expecta- 

 tion of having my results confirmed by other instruments 

 have made the earlier observations less numerous than they 

 otherwise would have been. It soon appeared that increas- 

 ing the number of observations would not materially change 

 the results that I had already deduced. However the con- 

 sistency of the observations in the several years may with 

 some add weight to the conclusions. 



My future exertions shall be directed in making such ob- 

 servations as may serve to throw further light on this subject. 



If I should meet with any circumstances that shall appear 

 to me to invalidate the conclusions 1 have now ventured to 

 make, I shall cheerfully communicate them, I shall be fully 

 satisfied with the consciousness of having, to the utmost, ex- 

 erted myself, as my duty led me, in the examination of this 

 important question. 



ing attended with a cloudy atmosphere. Clear skies oftener prevail during high winds. 

 These circumstances are much against the use of the plumb line. 



