The Art of Travel by Francis Galton : image 50

TABLE Foil ROUGH TRIANGULATION without the usual Instruments, and without Calculation.

Chord of angle situated at the opposite end of base to that from which we desire to learn the distance across the river.


			n	co		r-	.	00	-q" cA	Q>	-41 m	O	o	N			N	r	N		-41 w	a,		a~-i	-dn
	5	57	60	64	67	70	73	75	78	81	84	87	89	92	95	98	101	105	109	113	118	123	129	137	116
;q	5f	55	59	62	65	69	72	74	78	81	84	87	90	93	96	1.00	103	107	112	116	122	128	135	144	155
	6	54	57	61	64	68	71	74	77	80	84	87	90	94	97	101	105	110	185	120	126	134	142	153	167
st	61	53	56	60	63	67	70	74	77	80	84	87	91	95	99	103	108	113	119	125	132	141	151	161	1a2
	7	52	55	59	63	66	70	73	77	81	85	88	92	96	101	106	111	117	123	130	139	149	161	178	200
	7f	51	55	58	62	66	70	73	77	81	85	89	94	98	103	109	184	121	128	136	146	159	114	794	223
	8	50	54	58	62	66	70	74	78	82	86	91	95	101	106	112	118	126	134	144	156	170	189	215	253
0	8f	49	53	57	61	65	70	74	88	83	88	92	98	103	109	116	1.23	132	141	153	168	185	208	247	294
4	9	49	53	57	61	66	70	75	79	84	89	94	100	106	113	121	129	139	150	162	181	203	233
°	91	49	53	57	62	66	71	76	81	86	91	97	103	110	118	126	136	147	160	174	194	225	265	_
	10	48	53	57	62	67	72	77	82	88	94	1.00	107	115	123	133	145	161 1173		193	218
	101	48	53	58	63	68	73	78	84	90	97	104	112	120	130	1.41	154	171 1190		215	248
	11	49	53	58	64	69	74	80	86	93	100	108	117	127	138	151	166	187 211		--	-
	111	49	54	59	65	70	76	83	89	97	105	113	124	135	147	163	180	207 237		TO USE Tiff TABLE.
d	12	50	55	60	66	72	79	85	93	101	110	120	131	144	160	179	202
a	12f	50	56	62	68	75	81	89	98	106	117	128	141	157	1'15	199	229
as m																		Let AB be the baso of 100 feet, yards, minutes'
p o	13	52	57	64	70	77	85	93	103	113	125	138	155	173	196			journey, or whatever may be most convenient.
	13	53	59	66	73	81	90	99	109	121	135	151	171	194	224	C the point on the other side of the river.
	14	55	62	69	77	85	95	106	118	132	148	167	193					u'a" the chord of the angle at A to radius 10.
	14	55	62	69	77	85	95	106	118	132	148	167	193					Vb the chord of the angle at B to radius 10.
~																		Vb the chord of the angle at B to radius 10.
	141	57	65	73	81	91	102	114	129	145	161	191	223	To find AC, enter the Table with a'a." at the side, and with b'b" at the top.
o	15	60	68	77	87	99	110	126	143	164	184	-- To find BC, enter the Table with b'b" at the side,
	15 f	64	73	83	95	108 1123		141	163	191	218	and v,ith a'a" at the top.
0	16	69	79	90	105	121 '140 1164			193.			-
	161	76	88	103	120	141 166 199			l•b 243 b'iple : 10paces00 yards; Al 87 yards
						1 I			BP = 48 yards.