William Far, November 30, 1807-April 14, 1883, in the 1850’s found the answer to the spread of cholera in London, England. Farr gathered statistical evidence to try to support the miasmic theory. He demonstrated statistically that cholera was spread by polluted air by showing that the likelihood of dying of the disease was linked to the height that the victims lived above the River Thames. He interpreted this as support for the miasmic theory - the air at lower altitudes being dirtier. However he also obtained details of where different water companies drew their water, and generated statistics on the number of deaths per water company. He discovered that people supplied with water from two companies in particular- the Southwark & Vauxhall and the Lambeth water companies - which drew their water directly from the Thames were particularly likely to suffer from cholera. There was an another cholera epidemic in 1866, by which time John Snow had died. William Farr now accepted Snow's explanation. Farr produced a monograph which showed that mortality was extremely high for people who drew their water from the Old Ford Reservoir in East London. By this time, the germ theory of disease had become more widely accepted and Farr's work was considered conclusive. The consequence was that public health measures were now directed towards the real cause of cholera. In particular, large engineering projects were started in many cities to collect and treat sewage, ultimately eliminating the disease in industrialized countries.