Photo of a Holt 10 ton tractor at Soldier Field, Chicago, in 1924. Since Soldier Field was not completed until the fall of 1924 and appears to still be under construction by this photo, it appears that the Holt tractor pictured was involved in the construction of the stadium. The Holt Company became part of the Caterpillar Company in 1925. The Caterpillar Company issued a series of historical photos from their old negatives in 1964, which included this one from the Holt Company.
There are no copyright marks on as can be seen by the front and back views. While the original negative and any possible photos date before 1925, I have licensed this as PD-pre-1978 as the Caterpillar Company issued a new set of photos from the original negatives and did not place any copyright marks on them.
At lower right, there's a series of numbers which are the original negative's number; this number is also seen below it in reverse.
United States Copyright Office page 2 "Visually Perceptible Copies The notice for visually perceptible copies should contain all three elements described below. They should appear together or in close proximity on the copies.
2 The year of first publication. If the work is a derivative work or a compilation incorporating previously published material, the year date of first publication of the derivative work or compilation is sufficient. Examples of derivative works are translations or dramatizations; an example of a compilation is an anthology. The year may be omitted when a pictorial, graphic, or sculptural work, with accompanying textual matter, if any, is reproduced in or on greeting cards, postcards, stationery, jewelry, dolls, toys, or useful articles.
This work is in the public domain in the United States because it was published in the United States between 1929 and 1977, inclusive, without a copyright notice. For further explanation, see Commons:Hirtle chart as well as a detailed definition of "publication" for public art. 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 (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.
{{Information |Description=Photo of a Holt 10 ton tractor at Soldier Field, Chicago, in 1924. Since Soldier Field was not completed until the fall of 1924 and appears to still be under construction by this photo, it appears that the Holt tractor pictured