APPENDIX B.—No. VIII.

Table for Finding the Distance of an Object at Sea.[1]

To use the Table, let an observer from the cross-trees measure the angle between the distant horizon and the enemy's water-line, and look into the Table with that angle; opposite to it, in the column marked distances, will be found the distance of the object in yards.

Yards.	Height of the Eye above the Level of the Sea, in Feet.
Distance.	20	30	40	50	60	70	80	90	100
	° '	° '	° '	° '	° '	° '	° '	° '	° '
100	3.44	5.37	7.29	9.21	11.11	13.00	14.47	16.34	18.16
200	1.50	2.46	3.43	4.39	5.35	6.31	7.27	8.23	9.18
300	1.12	1.49	2.26	3.04	3.41	4.19	4.56	5.33	6.11
400	.52	1.21	1.48	2.16	2.44	3.12	3.40	4.03	4.36
500	.41	1.03	1.25	1.48	2.10	2.32	2.54	3.17	3.39
600	.34	.52	1.10	1.29	1.47	2.05	2.24	2.42	3.01
700	.28	.44	1.01	1.15	1.31	1.46	2.01	2.18	2.34
800	.24	.38	.51	1.05	1.18	1.32	1.46	2.00	2.13
900	.21	.33	.45	.57	1.09	1.22	1.33	1.45	1.57
1000	.18	.29	.40	.50	1.01	1.12	1.23	1.34	1.45
1100	.16	.26	.35	.45	.55	1.05	1.15	1.24	1.34
1200	.15	.23	.32	.41	.50	.59	1.08	1.17	1.26
1300	.13	.21	.29	.37	.45	.53	1.02	1.10	1.18
1400	.12	.19	.27	.34	.41	.49	.57	1.04	1.12
1500	.11	.18	.24	.31	.38	.45	.52	.59	1.07
1600	.10	.16	.22	.29	.35	.42	.48	.55	1.02
1700	.09	.15	.21	.27	.33	.39	.45	.51	.58
1800	.08	.14	.19	.25	.31	.36	.42	.48	.54
1900	.08	.13	.18	.23	.29	.34	.39	.45	.50
2000	.07	.12	.17	.22	.27	.32	.37	.42	.47
2100	.06	.11	.16	.20	.25	.30	.35	.40	.45
2200	.06	.10	.15	.19	.24	.28	.33	.38	.42
2300	.05	.10	.14	.18	.22	.27	.31	.36	.40
2400	.05	.09	.13	.17	.21	.25	.29	.34	.38
2500	.05	.08	.12	.16	.20	.24	.28	.32	.36

No correct use of this Table can be made when the proximity of land may interfere with the distance of the horizon.