Hart treated it as obvious that such rules commonly identify the acts of law-making authorities as sources of law, conferring power on those authorities to make law, and that (subject to qualifications that are part of the communication model such as those listed above) the law becomes what a lawmaker conveys that it is to be, in the communicative act by which it exercises such a power. Under the new law, the criteria for targeting non-targets actually become more lenient than for targeting actual targets. For the most part, they were older and, as they had been in Texas longer, they had more to protect. In part, well-established media of communication like printing participated in this revolution, although most of the significant changes-such as the typewriter, the Linotype, and the high-speed power-driven rotary press-were achievements of the 19th century. The emergence of television as a universal medium of mass communication is therefore a phenomenon of the postwar years. The end of the war brought a setback to this new industry, but the airplane had evolved sufficiently to reveal its potential as a medium of civil transport, and during the interwar years the establishment of transcontinental air routes provided a market for large, comfortable, and safe aircraft.

The airplane is entirely a product of the 20th century, unlike the automobile, to which its development was intimately related. World War I gave a great impetus to this technological development, transforming small-scale scattered aircraft manufacture into a major industry in all the main belligerent countries, and transforming the airplane itself from a fragile construction in wood and glue into a robust machine capable of startling aerobatic feats. It should be observed also that technological innovations transformed the character of war itself. On land, steam fought a long rearguard action, but the enormous popularity of the automobile deprived the railways of much of their passenger traffic and forced them to seek economies in conversion to diesel engines or electric traction, although these developments had not spread widely in Europe by the outbreak of World War II. Smeaton’s work was backed by thorough research, and his services were much in demand.

Most countries have government-controlled agencies, such as the United States Bureau of Standards and the National Physical Laboratory of Great Britain, involved in a broad spectrum of research, and establishments in building research, roads and highways, hydraulic research, water pollution, and other areas. Research in the civil engineering field is undertaken by government agencies, industrial foundations, the universities, and other institutions. Many of these have their own engineering staffs, but for large specialized projects it is usual to employ consulting engineers. Central and local government engineering and public works departments are concerned primarily with maintenance, for which they employ direct labour. These aspects of civil engineering may be considered under the following headings: construction, transportation, maritime and hydraulic engineering, power, and public health. The consulting engineer may be required first to undertake feasibility studies, then to recommend a scheme and quote an approximate cost. In such a manner for the first time in the history of American aviation the Commander-in-Chief of the armed forces definitely took a stand in favor of an independent military air arm. The term was first used in the 18th century to distinguish the newly recognized profession from military engineering, until then preeminent. Henry Ford led the way in the adoption of assembly-line mass production; his spectacularly successful Model T, the “Tin Lizzie,” was manufactured in this way first in 1913, and by 1923 production had risen to nearly two million per year.

They have two children, Grant and Andrea. Shipment in liquid form from the Sahara and piping from the bed of the North Sea have been among the novel developments. Responsibility for maintenance extends to ancillary and temporary works where these form part of the overall construction. After construction a period of maintenance is undertaken by the contractor, and the payment of the final installment of the contract price is held back until released by the consulting engineer. The promotion of civil engineering works may be initiated by a private client, but most work is undertaken for large corporations, government authorities, and public boards and authorities. 1. If a State has two or more territorial units in which different systems of law apply in relation to matters dealt with in this Convention, it may declare that the Convention shall extend to all its territorial units or only to one or more of them.