French Pendulum Lengths

French Pendulum
Lengths

Most French movements are marked with the pendulum length stamped on the back plate. This consists of 2 numbers usually located at the bottom post. The number to the left of the post is POUCE and the number to the right is LIGNE. This is a French system of measurement and can be converted to beats per hour using the chart below.

Example: The highlighted cell indicates the pendulum is 7 pouce and 2 lignes. This equates to
8156 beats per hour. The beats per hour indicated relate to the Virtual pendulum length and small adjustments may be necessary to fine tune the time keeping of the clock.

	POUCE
L I G N E		3	4	5	6	7	8	9	10	B E A T S P E R H O U R
	0	12605	10917	9764	8913	8252	7719	7278	6904
	1	12434	10805	9684	8852	8204	7679	7244	6876
	2	12269	10696	9605	8792	8156	7640	7211	6847
	3	12111	10591	9529	8733	8109	7601	7179	6820
	4	11959	10488	9454	8676	8060	7563	7147	6792
	5	11812	10389	9381	8619	8017	7526	7115	6765
	6	11670	10292	9310	8564	7972	7489	7084	6738
	7	11534	10198	9240	8509	7928	7452	7053	6711
	8	11402	10107	9172	8456	7885	7416	7022	6685
	9	11275	10018	9105	8404	7843	7381	6992	6659
	10	11151	9931	9040	8352	7801	7346	6963	6633
	11	11032	9846	8976	8302	7760	7312	6933	6608