326 Mr W atts’ Remarks on Captain Eatery's ■ 
pendulum adopted by the Committee of the House of Com- 
mons, namely 39.13047 inches, which turned my attention to 
this important subject, as I found that this length differed very 
sensibly from that deduced from the formula of La Place, given 
in his Mecaniqne Celeste^ tom. ii. p. 151, and which he had de- 
duced from a set of the best experiments that he could procure. 
This formula gives 39.13881 inches for the length of the pen- 
dulum in vacuo^ vibrating seconds in the latitude of London ; 
and this length thus deduced, differs only two 10,000th parts of 
an inch from the recent determination of Captain Kater. 
Impressed with the importance of the subject,. Mr Davies 
Gilbert, (then Mr Davies Giddy,) resolved to submit it to the 
House of Commons, having first consulted most of the mathe- 
maticians in London, and laid the matter before the President 
and Council of the Royal Society. By that learned body he 
was authorised to state the subject to the Government; and, 
having obtained its sanction, he finally brought it before Par- 
liament, by moving. 
That an humble address be presented to the Prince Re- 
gent, praying that his Royal Highness would be graciously 
pleased, to give direction for ascertaining the length of the pen- 
dulum vibrating seconds of time in the latitude of London, as 
compared with the standard measure now in the possession of 
this House ; and for determining the variation in the length of 
the said pendulum, at the principal stations of the trigonome- 
trical survey, extended through Great Britain ; and also for 
comparing the standard measure with the ten millionth part of 
the quadrant of the meridian, now used as the basis of linear 
measure on the Continent of Europe.” 
This address, which was moved on the 15th March 1816, 
was immediately answered by a reference to the Astrono- 
mer Royal, in the first instance, and by a request that 
the Royal Society would be assisting therein. A committee 
was accordingly appointed, and various plans immediately put 
into execution for determining the length of the second’s pen- 
dulum in London, principally consisting of modifications in the 
manner of suspending and applying a cylindrical rod. No soon- 
er were these measures known in France, than the Institute no- 
tified a wish for sending two of its members to assist in extending 
