Calendar: 1891-1892 Page 831

engineering department cxliii from the lower end of the beam if the beam be inclined at an angle of 45 to the horizon 10 Three equal forces act at the centre of the circum- scribing circle towards the angles of triangle ABC If be the intersection of the perpendiculars from Β and on the opposite sides of the triangle prove that OL will repre- sent the resultant of the forces -architecture an& JS mitring Construction SECOND YEAR Define centre and its use At what angle do arch stones slide in hard and soft stones Give sketches of forms of centres-one for span under 20 feet and one for large span also give sketch of the wedge used for large centres What is the usual inclination of roofs when covered with the following materials copper common slates plain tiles and thatch Also give the weight of each per 100 feet super Give line sketch of king post truss and enlarged sketch of the several joints also names of the timbers Explain Bellidor's method of forming Mansard roof and give sketch What are the general principles that govern the form and construction of iron roof-trusses Give line diagram of an iron-trussed rafter roof and detail sketches of the various joints What are the characteristics of good and bad timber Also describe wet and dry rot stating in what way they differ Describe the effects of the following impurities on cast and on wrought iron Phosphorus י Manganese" "Sulphur'' and "Arsenic יי