The April 1955 issue of Popular Electronics included an article about contra-polar energy - a kind of negative energy that, so it was claimed, would cause electrical devices to produce the opposite effect of what they normally would do. For instance, if contra-polar energy were applied to an ordinary table lamp, the bulb would cast darkness instead of light. Similarly, if applied to a soldering iron or a hot plate, the devices would grow freezing cold. Contra-polar energy technology was said to have been developed during World War II, but had recently been declassified because of its potential use to the general public. The article elicited enormous interest from readers, with many writing in requesting more information. And they continued to do so for years, forcing the magazine to have to point out twice that the subheading of the article, which read In keeping with the first day of April, should be taken literally.