Issue 2

Membership etc.

The soundness of Portland cement, i.e., its freedom from expansion (“invariabilite de volume” or “Volumenbestandigkeit,” to give its French and German equivalents respectively), is its most essential property, and should be always the first thing to be determined in estimating the constructive value of a sample. It is obvious that, notwithstanding other highly desirable qualities which a cement may possess, such as great strength or large sand-carrying capacity, if it is unsound, and contains certain elements which subsequently cause expansion, with, i n extreme cases, disintegration and crumbling, it is not only of no use as a constructive material, but is at once converted into a destructive material. Although with the improved methods of manufacture obtaining of recent years these extreme cases of disintegration have become more and more rare, expansion of a more or less dangerous nature is not infrequently met with. D B Butler

Among the varied uses to which reinforced concrete is now put the construction of bins for the storage of materials of various kinds takes an important place. Reinforced concrete bins have been constructed for holdiilg grain, coal, cement, ore, broken stone, sand, and other materials. It seems established now that not only does reinforced concrete possess in a supreme degree the qualities of fire-resistance and long life, in which respects it is superior to steel, that has been used largely for the construction of silos in preference to timber, but it originally costs no more and sometimes less than steel, while the cost of frequent painting and repairs is saved. Steel bins cost 50 to 100 per cent. more than timber bins of moderate size. H Kempton Dyson

Perhaps it would be of interest to the members to say a few words as to aluminium before we proceed to the general question of the new industry in the West Highlands of Scotland. It was not until 1827 that the metal was definitely discovered by a German chemist, but owing to the enormous cost of production it could not be used on a commercial scale until comparatively recently. A Alban H Scott

The subject of the present communication is one in regard to which it may be assumed that the available evidence is either inconclusive or of a more or less negative character. For, notwithstanding that cases are on record of destructive changes in tanks and sewers, the opinion tends to prevail that when the concrete construction is sound no marked disintegration need be anticipated, neither from sewage nor from its emanations. Sidney H Chambers