The materials should be spread in layers not exceeding 3 inches in thickness, and then incorporated in a steam mortar mill, or bylechuki, with sufficient water to make it into a stiff paste. Mortar which has once commenced to set should on no account be used in any work. _Kunkar_ or Hydraulic lime must invariably be used for waterworks and for wet foundations. [Sidenote: Soorki.] _Soorki_ must be made from well burnt brick-bats, and must pass through a sieve of 1⁄16 × 1⁄16 mesh. Freshly burnt bats must only be used. [Sidenote: Sand.] Sand must be clean, sharp, and free from dirt. [Sidenote: Khoa.] _Khoa_ must be broken from thoroughly burnt bricks to pass through a ring of 1½″ diameter. [Sidenote: Cement.] Portland cement must be of the best quality of English manufacture and comply with the standard tests. [Sidenote: Cement Plaster.] Cement plaster to be made of one part of Portland cement to two parts of sand, and must be properly mixed and applied fresh, the thickness of each layer to be ½″ finished. The surface must be kept covered with wet bags or straw for at least three days, after it has been completed. [Sidenote: Bricks.] Bricks must be hard, well burnt, sound, true to shape and size, and free from flaws and other imperfections, and to be of approved sample. [Sidenote: Brick-Work.] Bricks must be laid true to line and level, with joints not exceeding ⅜″ in thickness, and of approved bond. They must be soaked in water for at least four hours before being used. All joints must be raked out to a depth of ½″, while the mortar is fresh. [Sidenote: Pointing.] All joints to be at least ½″ in depth, and thoroughly cleaned out by watering and rubbing with a brush. Mortar for pointing to be composed of one part of lime and one part of _soorki_, ground very fine in a mill, or strained through coarse cloth. Flush pointing to be lined off true horizontally and vertically with a string, the lines thus made to be deepened by a rule made for the purpose. [Sidenote: Culverts.] The type of culverts adopted must be dependent on the depth of the drain below the surface of the road. Where arching can be done it is preferable. Where impracticable, the top should be covered with stone slabs. Parapets should be provided with stone copings. All culverts on a road or street should be numbered, and registered in the form given in Appendix G, page 74. The system of quadrennial repairs to bridges and culverts is an essential towards efficient administration, and when once successfully introduced, is economical. In masonry buildings a damp-proof course, which may be made with either asphalte, or with a layer of Portland cement 1″ in thickness, laid at the top of the plinth, and just above floor-level, is most desirable in order to prevent damp rising in the walls, if for no other reason than that it prevents damage to the masonry, and to the plastering, or pointing.