Appleton's dictionary of machines, mechanics, engine-work, and engineering (1869)
New York, Appleton · leaf 624
efraction, however, is too considerable to beneglected in estimating the range of a light, or in computing the height of a tower which is required tegive to any light a given range; and we must, therefore, in accordance with the influence of this elementon the one hand increase the range due to any… … Referring to the accompany ing B ! in \\ hich SdL is a segment of th i face, o (Tn* centre of the earth, I. I. a lighl bouse, and s the position of the marin< r*a eye, we obtain the ralue ofLLssH, the height of the tower in feet by the formula, .(1.) .r. which / — the distance in Engliah mile*…
Mechanical engineering
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