

Proceedings of the Royal Society, 299 



that of the double star £ Ursae majoris, an angle of nearly 14° has 

 thus been described by the two stars about their common centre of 

 gravity, in an interval of less than 2 years : thus affording every 

 probability that in a very few years we shall arrive at a perfect 

 knowledge of the figure, elements, and position of their orbits, 

 and be enabled by strict calculation, to answer the important 

 question, whether the Newtonian law of attraction is confined to 

 our own system, or obtains also in the sidereal heavens. (H.) 



Thursday, Nov. 24. — A paper was read, entitled An Account of 

 the Construction and Adjustment of the new Standard of Weights 

 and Measures of the United Kingdom of Great Britain and Ireland, 

 by Captain Henyr Kater,F.R.S. 



The author, after stating that the weights and measures of the 

 United Kingdom are founded on a standard, whose length is deter- 

 mined by its proportion to that of a pendulum vibrating mean 

 time in London, which has been ascertained by him to be 39.13929 

 inches of Sir George Shuckburgh's scale, deems it necessary, on 

 account of the importance of the result, to consider what degree 

 of confidence it is entitled to. For this purpose it is necessary to 

 compare this final result with those obtained in other experiments 

 and by different methods. Now it appears that previous to the 

 experiments detailed in the author's paper on the subject in the 

 Phil. Trans, for 1818, on which this result rests, another series is 

 there mentioned, made with the same instruments, but under cir- 

 cumstances which occasioned their rejection, and which owing to 

 some repairs in the instruments between the two series, which oc- 

 casioned a material alteration in the distance between the knife 

 edges, have all the weight of experiments made with a different 

 pendulum. The result of these rejected experiments, however, 

 differed only two ten-thousandths of an inch from that ultimately 

 adopted. 



The author next compares the lengths of the seconds' pendulum 

 at Unst and at Leith Fort, as ascertained by him by an invariable 

 pendulum, whose vibrations had previously been determined in 

 London, and whose length was thus known in terms of the London 



