IN Electrical Industries of July, W. Fennell gives a review of the salient engineering features of the Belgian Grid, which began by the co-operation in 1919 of isolated supply companies. These companies, mostly in the southern and eastern provinces (Liège, etc.), happened to be in close contact with heavy industries. They realized the existence of by-product power 'going to waste' at the large industrial works and saw that in some cases it would be economical to use this power rather than to build large power stations or extend small ones. A power production combine was formed to further the interests of manufacturers who had blast furnace and coke oven gas and process steam available greatly in excess of their own power requirements. In addition, they had engines used as stand-by plant, much of which would not be necessary if the various works' plants were interconnected. The electricity supply companies also had means of utilizing the waste power. This combine has spread so that it includes practically the whole country under a grouping system. All the undertakings and associated works are linked up into two networks, north and south, which are themselves interconnected. The production of power, while remaining under local control, is directed by a national co-ordinating company. The tariff applied to plant owners is based on the principle that the amounts they pay or receive are equal to the reduction or increase of expenditure entailed in their installations by running in parallel, compared with independent working. The success that Belgium has attained as a competitor in the steel and chemical industries indicates that this co-operative experiment, now twenty years old, has been a substantial contributory cause.