320 Capt. Kater’s ExperiTnents for Determining tlie Variation 
Results of the Operations. 
It now remains to give in one view, the results of the opera^. 
tions that have been detailed. These are comprised in the fol- 
lowing table. It would have been desirable to have expressed 
the length of the pendulum vibrating seconds, in parts of the 
scale which forms the basis of the Trigonometrical Survey of 
Great Britain, the Commissioners of Weights and Measures 
having agreed to recommend that the “ standard used in the 
Trigonometrical Survey of Great Britain should be considered as 
affording the most authentic determination of the linear measure 
of the United Kingdom.” But as experiments are yet wanting 
to enable me to do this with sufficient accuracy, I have given 
the length of the pendulum in parts of Sir George Shuckburgh’s 
standard scale, the correction for the difference between which, 
and the national standard of linear measure, may be readily ap- 
plied hereafter. 
The length of the pendulum vibrating seconds in the latitude 
of London, is stated in the Phil. Trans, for 1818, to be 39,13860 
inches. But I have here to notice a very important omission, 
which I am obliged to Mr Troughton for having pointed out in 
the first number of the Edinburgh Philosophical Journal. It 
may be seen, that in computing the specific gravity of the pen- 
dulum, I have neglected to include the deal ends. Anxious to 
supply this omission in the most unexceptionable manner, I 
thought it best to take the specific gravity of the whole pendu- 
lum, and for this purpose requested Mr Barton, Comptroller of 
his Majesty’s Mint, to allow me the use of the fine balance 
lately constructed under his directions, a request with which he 
most obligingly complied, and favoured me with his assistance, 
and with every requisite for making the experiment. 
A deal trough was prepared, seven feet long, nine inches 
wide, and the same depth. The pendulum was slung horizon- 
tally from the scale pan, by a fine iron wire. The weight of 
the whole was carefully determined in air, and found to be 
66904 grains. The trough which had been previously placed 
beneath the pendulum, was then filled with distilled water, 
and the weight of w^ater displaced was found to be 9066 grains. 
The small portion of iron wire which \yas immersed in the wa- 
