. The Civil engineer and architect's journal, scientific and railway gazette. Architecture; Civil engineering; Science. Fig. 1. Draw Bb through the centre 0, then will the arc ab â¢= arc A B, which we shall put = 20 (p in this example, and proceed to measure a i as in example fig. 5, page 314. Lay off a 4 from 4 to c; from c to d; from d to e; from e to/; homftog. Putting ja = A,, then 108 6 X 20(J> -^ A, = 360° = â/3; because 360° 21600 11 108 36° 40' "~ 2200 Layoff, as before directed, J a, = A j, from a to A, from A to s, and J to/; then calling s t, Aâ, we have 3A, + A, ^ 20<
. The Civil engineer and architect's journal, scientific and railway gazette. Architecture; Civil engineering; Science. Fig. 1. Draw Bb through the centre 0, then will the arc ab â¢= arc A B, which we shall put = 20 (p in this example, and proceed to measure a i as in example fig. 5, page 314. Lay off a 4 from 4 to c; from c to d; from d to e; from e to/; homftog. Putting ja = A,, then 108 6 X 20(J> -^ A, = 360° = â/3; because 360° 21600 11 108 36° 40' "~ 2200 Layoff, as before directed, J a, = A j, from a to A, from A to s, and J to/; then calling s t, Aâ, we have 3A, + A, ^ 20<p; and we find that s t is contained 28 times in the arc a 4 ; 108 .-. 120^ -^ ^, = â&; 3^1 â (â Aa = 209; and 28Aj = 20?. Eliminating A, and A^, we find 29205 fl = p = 12-9 times © nearly ; 2268 f 1 , .â¢. 36° 40' «= Z A 0 N is laid off with as much ease and certainty as by a protractor. As a second example, let it be required to lay off an angle of 132° 27'.â From 180° 0'take 132° 27' = 47° 33', which put = $. 360° 2400 r , vâ â^ââ when put = -, then -B = 360° = tt. 47" 33' 317. Fig. 2. Referring to fig. 2, we have laid off 29 small arcs from A to 29 = â¬. AB = <ii = ic ~ cd = de =⢠ef. And a j = S h'^of = A,; hg = A^.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original London : [William Laxton]
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Keywords: ., boo, bookcentury1800, booksubjectarchitecture, booksubjectscience
