 | William Mudge, Isaac Dalby, Thomas Colby - 1801 - 690 pages
...angles 6AB, aBA, or the sum of the two refractions ; hence, if we suppose half that sum to be the mean refraction, we have the following rule, when the objects...the remainder is the mean refraction. If one of the objects (B) instead of being depressed, is elevated, suppose to the point G, the angle of elevation... | |
 | Thomas Keith - 1810 - 478 pages
...( / Bpf + / Asa) = / a sP + / £PS the sum of both the refractions. Hence the following ( Y) RULE. Subtract the sum of the two- depressions from the...arc, and half the remainder is the mean refraction. (Z) If one of the objects (A) instead of being depressed, be elevated, suppose to the point ey the... | |
 | Thomas Keith - 1826 - 504 pages
...— (L Asa+ ¿BPÔ) = ¿.asv+ ¿ÔPS the sum of both the refractions. Hence the following (Y) RULE. Subtract the sum of the two depressions from the contained...arc, and half the remainder is the mean refraction. (Z) If one of the objects (A) instead of being depressed, be elevated, suppose to the point e, the... | |
 | Thomas Keith - 1839 - 498 pages
...L OSP + L OPS) — ( l_ Asa + L ~BPb) =: L c — ( L Asa + L Bpfi). Hence the following (170) RULE. Subtract the sum of the two depressions from the contained...arc, and half the remainder is the mean refraction. (171) If one of the objects (A) instead of being depressed, be elevated, suppose to the point e, the... | |
 | John Gregory - 1843 - 350 pages
...give the refraction. Hence the following rule, when both objects are reciprocally depressed. Deduct the sum of the two depressions from the contained...remainder is the mean refraction. If one of the points, B, be elevated to the point g, instead of being depressed, then the rule is, subtract the depression from... | |
 | P. O'Shaughnessy (Civil engineer) - 1848 - 110 pages
...true refraction. Hence comes the following rule, when both objects are reciprocally depressed. Deduct the sum of the two depressions from the contained...arc, and half the remainder is the mean refraction. But if the point B, be elevated to the point X, instead of being depressed, then the rule is, substract... | |
 | Edward Charles Frome - 1850 - 292 pages
...their sum, taken from the angle Cf (the contained arc of distance), will leave the angles b AB, aBA, the sum of the two refractions ; hence, supposing...suppose to the point g, the angle of elevation being g AD, then * " Trigonometrical Survey," TOl. ip 175. See also, on the subject of refraction, Woodhouse's... | |
 | Anthony Nesbit - 1859 - 494 pages
...ASa + Z. BP6) =(Z. OSP + Z. OPS) —(Z.ASa + Z.BPi)=ZC—(Z.ASa + Z.BP6). Hence the following RULE. Subtract the sum of the two depressions from the contained...the remainder is the mean refraction. If one of the objects (A), instead of being depressed, be elevated, suppose to the point e, the Z of elevation being... | |
 | Edward Charles Frome - 1862 - 336 pages
...therefore their sum, taken from the angle Ct (the contained arc of distance), will leave the angles b AB, a BA, the sum of the two refractions ; hence, supposing...are reciprocally depressed. Subtract the sum of the ttco depressions from the contained arc, and half the remainder is the mean refraction : — * Carr-s... | |
 | Edward Charles Frome - 1873 - 384 pages
...their sum, taken from the angle C t (the contained arc of distance), will leave the angles b AB, a BA, the sum of the two refractions; hence, supposing...arc, and half the remainder is the mean refraction. * Carr's "Synopsis of Practical Philosophy,"articles 'Levelling'and 'Refraction.' t "Trigonometrical... | |
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AB, aBA, the sum of the two refractions ; hence, supposing half that sum to be the true refraction, we have the following rule when the objects are reciprocally depressed. Subtract the sum of the two depressions from the contained arc, and half the remainder... 
