TY  - JOUR
T1  - Observations and Experiments on the Daily Variation of the Horizontal and Dipping Needles under a Reduced Directive Power. 
JF  - Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London (1800-1843)
VL  - 2
SP  - 197
EP  - 197
PY  - 1815/01/01/
UR  - http://dx.doi.org/10.1098/rspl.1815.0216
M3  - doi:10.1098/rspl.1815.0216
AU  - Barlow, P.
ER  -