Pocketbook of Useful Formulæ and Memoranda
for Civil and Mechanical Engineers

58 Molesworth’s pocket-book Formulæ for Constructing Tables of Earthwork. H and Ji = the heights of section in feet at each end of a chain length. C = cubic contents of 1 chain length, in yards. The two slopes are taken separately from the central part—the former as frustum of a pyramid 1 chain long, the latter the frustum of a wedge. FOK BOTH SLOPES. Frustum of pyramid C = X x (H2 + h* + H A). X = *204 in slopes | to 1. X= -408 „ | to 1. X= *815 „ 1 to 1. X = l-223 „ Ijtol. X=l-629 „ 2 tol. X = 2-445 „ 3 tol. FOR CENTRAL PAKT. C = k (H + h) frustum of wedge. £=19’56 when base=16 ft. (Occupation roads'). *=22-00 ” 4=24-45 £=34-23 £ = 36-67 £=40-34 Å=46-45 £=1*2222 B = 18 =20 = 28 = 30 = 33 ' =38 = B in feet. Single line railway. Ditto. Public road. Double line railway Ditto. Turnpike road. PRISMOIDAL FORMULA. [Sum of areas of both ends + (area of middle X 4)] X length