The effects of various intermediate targets on dispersion of shotgun patterns.

Intermediate targets cause dispersion of a shot pattern by a ricochet effect. Thus, the intermediate target must have sufficient thickness or tensile strength to slow down the initial group of shot striking the target. Aluminum and steel screen, ordinary window glass, thin cardboard and thin cowhide did not manifest these qualities under the conditions of these experiments.     

Oxford exploding spires

Barbara Ward in her keynote address to the Conference on Exploding Cities, held in Oxford England, made the point that the current problems of the cities can only worsen as the world's population doubles by the year 2000 and the worst hit will be the cities of the developing nations. Between 1950 and 2000 urban populations will rise from 500 million to 1000 million, but the equivalent rise in the 3rd world will be from 500 million to 2200 million. The Conference was more successful in identifying the problems and their causes than in proposing solutions. The inadequacy of urban transport was emphasized repeatedly. Crime emerges as another urban headache. Pollution was another popular theme, and shanties were thoroughly examined. Positive proposals too often took the form of self-evident truths. In all cases the message is clear: the 1st prerequisite to urban planning is central control and, if necessary, public ownership of land. A succession of speakers advocated more self-help for the communities which have emerged on the periphery of so many urban centers. Elizabeth Jelin, from Buenos Aires, argued that these communities -- and shanty towns are the most obvious manifestation -- should no longer be viewed as marginal. They perform essential services, especially in terms of employment, and cannot be moved without severe disruption. Self-help was the beacon held up to delegates, despite the warnings that it would lead to complacency on the part of authorities.