702 
ME. AIRY ON THE NEW NATIONAL STANDARD OE LENOTH. 
ADDENDUM. 
Since the preparation of this paper, the following bars have been lodged in the 
Exchequer Office of Weights and Measures, for use: — 
Line-Bar No. 30. 
^No. 70. 
No. 45. 
End-Bars < No. 76. 
No. 79. 
LNo. 81. 
1858, February 19. G. B. Amr. 
Note on the Tubular Scale of the Royal Astronomical Society. 
The information which the Committee possessed as to the discordance in the relative 
lengths of the intervals A«, B5, Cc, Dd, on this scale, as ascertained at different times 
(to which allusion is made in page 645), was derived from Mr. Bailt’s letters, and from 
an Abstract entered by Mr. Baily himself in his manuscript book of observations. On 
careful examination of those observations, in the course of reading the proof-sheets of 
this Account, it was found that Mr. Baily had given all the signs erroneously, for the 
observations of 1844, April 21. The signs as now printed in page 645 are coiTect. On 
examining into the effect of this change, it Avill be seen that the discordance is really far 
less than it was supposed to be by Mr. Baily ; and that the Tubular Scale merits greater 
credit than it obtained with the Committee and Mr. Sheepshanks. 
1858, March 3. 
G. B. Airy. 
