4oo Mr. cavendish’s Account of 
days of O&ober, 1775, except that marked *, which was 
tried on the 1 5th of the preceding April. 
TheSociety’s needle, 
Another of the fame 
conftrudtion, be- 
longing to Mr. 
NAIRNE, 
One of mine on i 
nearly the fame l 
conftru&ion, J 
Another needle ini 
the fame frame, J 
A needle of mine, i 
made by sisson, 
partly on the fame 
conftrudtion as 
Mr.LORIMERV'J, 
Another of Mr. 1 
nairnf.’s on the 1 
fame conftru&ion, 1 
Poles reverfed. 
Poles reftored to 
their firft iitu - 
ation. 
T rue 
Dip. 
Eaft 
Weft 
Eaft 
Weft 
Eaft 
Weft 
72 32 
CO 
72 9 
72 40 
72 59 
7 1 5 o 
72 23 
72 56 
72 29 
7 1 45 
73 21 
72 5 1 
72 27 
72 37 
72 33 
72 22 
71 41 
73 23 
72 34 
72 iS 
72 30 
72 22 
72 7 
71 40 
73 53 
72 16 
72 3 ° 
72 33 
*73 1 
7 1 49 
7 1 57 
73 0 
72 27 
73 8 
72 0 
73 J 5 
7 i -57 
72 35 
Each of the numbers fet down in the above table is 
the mean of two obfervations, the inftruments being ob- 
ferved firft with the front to the Eaft, then to the Weif ; 
then a fecond time to the Eaft, and then again to the 
Weft; and in all the obfervations, except thofe with the 
two laft inftruments, which are of a different conftruc- 
tion, care was taken that the needle fliould vibrate in very 
fmall arches when let down on the agate planes. By 
a mean of all, the true dip at London, at this time, 
comes out 7 2° 30', the different needles all agreeing 
(e) Sec Phil. Tranf. vol. LXV. p. 79. 
within 
