Deodorants Have Been Used For Centuries

Body odour was once an inevitable part of life, but thanks to a mystery inventor, modern society smells a lot nicer.

In 1881, an unidentified man in Philadelphia made the first antiperspirant to be sold commercially, known as "Mum".

The product was originally sold through his nurse and made with zinc, but later deodorants changed to aluminium chloride after complaints of skin irritation. It was originally sold as a cream in a jar.

Helen Barnett, an employee, was inspired by the invention of the ballpoint pen to suggest a roll-on applicator, which was introduced in 1952. The use of aerosol to apply deodorant did not begin until the 1960s.

The original Mum brand has many competitors but is still going strong. Procter & Gamble spokesman Simon Prenticebe configured on a mask to shine light on the same region of a photoresist. In a region on the photoresist where the light passing through one of the shifters is in phase with the light passing through the other shifter, a feature can be created on the photoresist that is narrower than the distance between the two shifters. Where the light passing through the shifters is out of phase, no feature is created. By reducing the distance between the two shifters, very small features can be created on the photoresist. The width of the feature can be considerably less than could be produced by the same optical system without phase shifting.
In a trenched PSM, the trenches are arranged to alternate with untrenched areas in order to provide