| Description | English: Teacher pointing to blackboard, from a 1924 advertisement |
| Date | 1924 |
| Source | Advertisement for Postum in The Delineator (https://archive.org/details/delineator104olou/page/n125/mode/2up) |
| Author | Anonymous |
The blackboard has been made blank. In the advertisement, the original message was “ ‘Children should not drink tea or coffee at all’ —U.S. Bureau of Education.”
