women began to take over men's work due to the great shortage of labour during the First World War (see Suffragette). At the same time, electricity, which had been introduced mainly for lighting and industrial use, began to be used for heating and the application of the electric motor at the small business and domestic level. As shorter hair was improved in appearance by waving even more than long hair, it was only a matter of time before an improved form of waving appeared. Nessler An early alternative method for curling hair that was suitable for use on people was invented in 1905 by German hairdresser Karl Nessler. He used a mixture of cow urine and water. The first public demonstration took place on 8 October 1905, but Nessler had been working on the idea since 1896. Previously, wigs had been set with caustic chemicals to form curls, but these recipes were too harsh to use next to human skin. His method, called the spiral heat method, was only useful for long hair. The hair was wrapped in a spiral around rods connected to a machine with an electric heating device. Sodium hydroxide (caustic soda) was applied and the hair was heated to or more for an extended period of time. The process used about twelve brass rollers and took six hours to complete. These hot rollers were kept from touching the scalp by a complex system of countering weights which were suspended from an overhead chandelier and mounted on a stand. Nessler conducted his first experiments on his wife, Katharina Laible. The first two attempts resulted in completely burning her hair off and some scalp burns, but the method was improved and his electric permanent wave machine was used in London in 1909 on the long hair of the time. Nessler had moved to London in 1901, and during World War I, the British jailed Nessler because he was German and forced him to surrender his assets. He escaped to New York City in 1915, buying passage on a steamship under an assumed name. In New York, he found that hundreds of copies of his machine were in use, but most did not work well and were unreliable. Nessler opened a shop on East 49th Street, and soon had salons in Chicago, Detroit, Palm Beach, Florida and Philadelphia. Nessler also developed a machine for home use that was sold