colony of rats on the surface and almost certainly numerous complaints to the control agency. In short, the uncontrolled populations of rats in sewers constitute a reservoir which extends into all parts of a city and is capable of establishing new infestations on the surface. The structural damage caused by sewer rats can be considerable. They are
The Saffir-Simpson scale measures the intensity of a hurricane. Wind speed is measured on a scale of 1-5 to give an estimate of potential property damage and flooding along the coast. The Categories are as follows: Category One Hurricane: Winds 74-95 mph.
   Seismometers-instruments that measure motions of  the ground.   The visual output, either on a monitor or on paper is called a  seismograph   Seismometers are in part used to measure the intensity of  earthquakes. The scale used to measure earthquake intensity is  known as the Modified Mercalli scale.