One clinical study looking at essential oils for treating children with eczema found that massage with and without essential oils helped improve dry, scaly skin lesions. Children with this scaly, itchy skin problem seem to have less redness, scaling, and other symptoms if they had massage between flares.
Serial numbers on firearms in US were made mandatory by the Gun Control Act of 1968.
In the US, Eli Whitney saw the potential benefit of developing interchangeable parts for the firearms of the United States military. In July 1801 he built ten guns, all containing the same exact parts and mechanisms, then disassembled them before the United States Congress.