Lethal gas fights crime, 1921; baby energy powers cleaning, 1871

This article was originally published with the title “50, 100 & 150 Years Ago” in Scientific American 324, 3, 74 (March 2021)
doi:10.1038/scientificamerican0321-74
ABOUT THE AUTHOR(S)
Dan Schlenoff
Dan Schlenoff is a contributing editor at Scientific American and has edited the 50, 100 and 150 Years Ago column for one seventh of the magazine’s history.
Credit: Nick Higgins