<P> The word "thermos" is a genericized trademark used as a name for a vacuum flask . From around 1910 till 1922, Thermos strove for this synonymity, as it was considered free advertising; the value of such advertising was estimated, in 1917, at between $3 and $4 million worth in American dollars alone . As the company and vacuum flask market grew, it became increasingly protective of its trademark, which it registered in 1923, following a narrow lawsuit victory over flask manufacturer W.T. Grant Company . Starting in 1935, Thermos employed a clipping service to find unauthorized usages and protested to dictionary editors who included "thermos ." A 1940 internal memo said the definitions "undoubtedly would be cited against us in a lawsuit to defend the trademark . The best we can do is to try to' purify' the definition of the word ." Into the 1950s, Thermos continued its efforts to protect it, creating various products (tents, lanterns, campstoves) bearing the name to affirm it as a brand name, not an item . </P> <P> In 1958, Aladdin Industries announced intent to sell "thermos bottles," and Thermos sued for infringement . In 1962, Judge Robert Anderson ruled that "thermos" was a generic term, due largely to Thermos's own publicization and lack of diligence in defending the trademark . Aladdin (or any company) could mark its bottles with a lowercase "thermos," while Thermos, then called The King - Seeley Thermos Company, retained the uppercase usage . </P> <P> Invented in 1892 by Sir James Dewar, a scientist at Oxford University, the "vacuum flask" was not manufactured for commercial use until 1904, when two German glass blowers, Reinhold Burger and Albert Aschenbrenner, formed Thermos GmbH . They held a contest to name the "vacuum flask" and a resident of Munich submitted "Thermos," which came from the Greek word therme, meaning "heat ." </P> <P> The thermos is commonly called the Dewar flask among chemists in recognition of its inventor, James Dewar . Dewar did not register a patent for his invention and it was subsequently patented by Thermos, to whom Dewar lost a court case in claiming the rights to the invention . </P>

When were the first thermos flasks produced for commercial use