Some years ago, the city engineer of Liverpool, Mr. John A. Brodie, M.Inst.C.E., one of our most enterprising city engineers, essayed a bigger step forward. He was faced with the disposal of 50,000 tons of clinker from the city destructors during the year. He made a bold effort to turn it to economic account in the obvious directions--paving and kerbing operations--but these channels absorbed only a round 20,000 tons, leaving some 30,000 tons to be shipped to sea to be dumped at a total annual cost of nearly £4,000--$20,000. The city authorities had resolved to carry out a tenement building scheme, and the city engineer decided to provide them in concrete and to use the refuse from the destructors as the aggregate, exacting tests having convinced him of its suitability for this purpose. The building, covering an area of 3,717 square feet, of which total 1,611 square feet are open space, is of three floors with four tenements on each floor, finished off with a flat roof, surrounded by a parapet for washing, drying, or playground purposes. The construction of the building was carried out upon the section or slab system. That is to say the walls, floors, ceilings, and other parts, with all necessary openings, were moulded at the destructor works, and set aside for a time to mature. Some of these slabs were of imposing dimensions, ranging up to 16 feet in length by 13 feet wide, 14 inches thick and weighing 11 tons. Upon arrival at the site they were slung into position and dovetailed into place, thus forming a rigid structure. As an indication of how modern thought may be hampered severely by prevailing notions it may be stated that, as a result of his deductions and experiments, the engineer decided that a thickness of 7 inches for the walls would be adequate. But his decision was over-ruled. The existing regulations insisted that brick walls should be 14 inches thick and the concrete had to comply with these rules. The result of this indefensible policy, for which misconception and lack of knowledge were responsible, was to double the weight of the structure and to inflate the cost of the buildings to an unnecessary degree. The engineer computed that if construction were carried out upon the lines he advocated the building could be completed, including the provision of all necessary plant, for £1,230--$6,150. Enforced compliance with obsolete rules inflated the cost to £4,072--$20,360. In other words the ratepayers of Liverpool were compelled to spend £2,842--$14,210--more than they need have done--a flagrant waste of money, material, time, labour, and knowledge.