What is john leal?

As an AI Language Model, I have found several people with the name John Leal in a quick search, but I am assuming you are referring to John R. Leal who was an American civil engineer, public health official, and water treatment expert. Leal was born in Havana, Cuba in 1858 and died in Paterson, New Jersey in 1914.

John R. Leal is best known for his work to improve public health by introducing chlorine as a disinfectant in water treatment plants. In 1908, he persuaded the town of Jersey City, New Jersey, to become the first in the world to chlorinate the public water supply. This helped combat waterborne diseases, such as typhoid fever and cholera, that were widespread at the time.

Leal also served in a number of positions within the field of public health, including as the Chief Engineer of the Jersey City Water Supply, a member of the American Water Works Association, and a member of the New Jersey State Board of Health.

Overall, John R. Leal's contributions to public health and his innovative use of chlorine disinfection in water treatment have helped save countless lives and have had a lasting impact on public health practices worldwide.