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lii oonnestion with the inmufacturo of bitumen from semi-asphaltio petroleums such as are found in Texas an I southern Illinois, it is desirable to know that usually the blowing process, as well a-s th > dis'.ill xtion pr 08633 ha 3to be used, although subjecting the oil to a special preliminary cracking pr 03633 may make blowing unnecessary. Blown asphalts have a much higher melting-point for a given penetration and a much lower ductility and lower specific gravity. For the purpose of fluxing solid or semi-solid bitumens in England tar is very often used, but 1 would not recommend the use of tar in this country. Liquid asphalts should bo used. Costs. While costs of various pavements abroad aro not of very much use in this country, the following information may be of some interest. Generally speaking the cost of pavement-construction is heavier in England, than in America, although wages are considerably loss. In Los Angeles the average costs of city pavements at present rates of exchange are as follows : — Per Square Yard. Asphalt pavement — s. d. 5 in. concrete base, paint binder 1.1 in. surface .. .. .. .. 1.0 6 5 in. concrete base, 1 in. asphalt-concrete binder, 2 in. surface .. .. .. 10 11 6 in. concrete base, 1 in. binder, 2 in. surface .. . . .. .. .. f 2 2 3| in. bituminous base, ljin. surface .. .. .. .. .. 7 11 5 in. bituminous base, 1| in. surface .. . . .. . . .. ..98 Warrenite-Bitulithic — 3| in. bituminous base, 1 .-*,- in. surface .. .. .. .. .. 8 10 5 in. bituminous base, 1| in. surface .. .. .. .. .. 10 6 5 in. concrete base, paint binder 1| in. surface .. .. .. ..10 11 (iin. concrete base, paint binder 2 in. surface .. .. .. .. 12 7 Topeka pavement, Sin. concrete base, paint binder 2 in. surface .. .. 10 6 Concrete pavement, 5 in. thick .. .. .. .. .. .. ..98 Concrete pavement, 6 in. thick .. .. .. .. .. .. ..108 Concrete pavement, 7 in. thick .. .. . . .. .. .. ..119 I'm- Square Yard. The following shows some very recent typical London prices : — s. d. s. d. Asphalt pavement, 5 in. thick .. .. .. .. .. 17 6to 21 0 Asphalt pavement, 2 in. thick with two years' maintenance .. .. 12 oto 15 0 Wood block on 9 in. concrete foundation .. .. .. .. .. 38 3 Rock asphalt, \\ in. thick, with one year's maintenance .. .. .. 12 0 Wood block on 12 in. concrete base .. .. .. .. .. 54 2 12 in. concrete foundation only .. . . .. .. .. .. .. 30 0 4 in. tar-slag macadam .. .. . . .. .. .. .. ..82 2 in. asphalt carpet .. .. .. .. .. .. .. .. 10 5 Rubber pavement .. .. . . . . .. .. . . . . 80 0 Tar-spraying and gritting .. .. .. .. .. .. 0 4to 0 5 Per Square Yard. The Chester City Council has carried out work recently for the following prices : — s. d. Granite sets on 7 in. reinforced-concrete foundation .. .. .. .. 32 6 2 in. rock asphalt on 7 in. reinforced-concrete foundation .. . . . . ..210 4 in. wood block on 7 in. reinforced-concrete foundation . . .. .. .. 28 10 5 in. wood block on 7 in. reinforced-concrete foundation .. .. .. 31 10 2 coat bituminous macadam .. .. .. .. .. .. ..163 4 in. penetration pavement .. .. .. .. .. .. ..110 7 in. reinforced-concrete tar-sprayed .. .. .. .. .. ..166 Recording Costs. —Elaborate costing systems are a feature of a number of American jobs. It would be impossible to get the average New Zealand foreman or overseer to carry them out satisfactorily. They usually seem to be operated in the United States by university graduates in engineering, who, to gain experience on works, take up subordinate positions as timekeepers, &c. There always seems to be an ample supply of such men for reasonably large jobs. In Now Zealand there is a very great field for improvement in recording costs, but accuracy and up-to-dateness should never be sacrificed for detail. In. general it may be said that engineering costs cannot be entirely entrusted to a book-keeper or accountant; the value of the record consists in the data being reduced to units that will be immediately applicable to future work in the statement of the conditions governing the data, and in tho logical arrangement and clearness of tabulation employed. Plant. With the groat increase in road-development and the big changes in type of construction during the, past ten years there has been considerable activity in the design and manufacture of new plant, particularly in America. Motor-trucks and Steam-wagons. —Where haulage of road-materials over good surfaces is required the heavy motor-truck or steam-wagon is most efficient. Unfortunately we have in New Zealand very few roads capable of withstanding such heavy traffic except in the driest of weather, and comparatively light trucks on pneumatic tires would appear to be the most suitable for construction