Modern Gasworks Practice

48 MODERN GASWORKS PRACTICE is very prone to get rid of his old broken retorts on such occasions, and in many instances there is little reason why these should not be used in moderation. It must be remembered, however, that the modern highly porous retort has a low crushing strength, and in view of this faet it is best excluded from the more important work. Cement concrete is nearly always used nowadays in preference to the lime variety, owing to its greater strength, and should seldom be mixed in higher ratios than 1 to 6, unless the ground is good, in which case a mixture of 1 to 8 or 9 may be safely used. The aggregate is best composed of a fairly coarse ballast, or hard bricks broken to a size not exceeding 2 inches, with an adequate proportion of sand. Gare must be taken to see that all mortar adhering to the bricks is removed. Concrete mixers are a present-day fashion, but except for extensive building operations in reinforced work it is questionable whether they effeet any marked economy. Many authorities are of the opinion that the hand-mixed material is far superior. For brickwork purposes cement mortar, though. more costly than the lime variety, should be used whenever possible. If lime mortar is to be used, however, a satisfactory mixture will be obtained by the following proportiöns : 1 of lime to 3 of sand. It has been said that for cliimney work lime mortar is more suitable owing to its being more elastic than cement mortar. It is difficult to lay down any hard and fast rule for the cost of foundations, but in the case of the ordinary rectangular slab an average figure at the present time would be 40s. to 50s. per cubic yard complete, including excavation to a depth not exceeding 4 feet. Excavation only varies from 2s. Qd. to 4s. 3d. per cubic yard up to a depth of 4 feet; beyond this depth the cost will range between 4s. Gd. to 7s., which includes light timbering. MODERN GASWORKS BUILDINGS Engineers in the past have not neglected to add an artistic touch to the archi-tecture of the gasworks, and evidence of this is seen in the cast-iron embellish-ments, finials, etc., introduced for the supposed beautification of certain plant and buildings. It would appear, however, that the tendency of the present age is in the direction of utility alone, it being realized that under no circumstances can a gasworks be represented as ornamental; hence simplicity of design has commenced to assert itself at every turn. So far as the general style of buildings is concerned, economy goes hand-in-hand with simplicity of outline ; accordingly these two must rank as primary considerations. Other factors bearing on the ultimate decision are :■— (a) Wear and tear, the cost of maintenance, re-painting, etc. (b) The choice of materials suited to the purpose for which. the building is required, e.g. in corrosive atmospheres material such as corrugated iron should be dispensed with.. (c) Adaptability for future extensions without the necessity for considerable destruction. (<Z ) Ampie provision for the reception and dispatch of materials in connection