Though the title page inside the book did, in fact, bear a copyright notice, a search at https://onlinebooks.library.upenn.edu/cce/ shows that the copyright was not renewed. The handbook is therefore public domain.
Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (70 years p.m.a.), Mainland China (50 years p.m.a., not Hong Kong or Macao), Germany (70 years p.m.a.), Mexico (100 years p.m.a.), Switzerland (70 years p.m.a.), and other countries with individual treaties.