To better adapt it to his respective Wikipedia article, the ad was cropped and cleaned in a graphics editing program. The original can be viewed at the source below.
This advertisement (or image from an advertisement) is in the public domain because it was published in a collective work (such as a periodical issue) in the United States between 1929 and 1977 and without a copyright notice specific to the advertisement. Unless its author has been dead for several years, it is copyrighted in jurisdictions that do not apply the rule of the shorter term for US works, such as Canada (50 p.m.a.), Mainland China (50 p.m.a., not Hong Kong or Macao), Germany (70 p.m.a.), Mexico (100 p.m.a.), Switzerland (70 p.m.a.), and other countries with individual treaties. See this page for further explanation.