Quantcast
issue
Read articles, including Science News stories written for ages 9-14, on the SNK website.

OLD TIME. Telegraph system, circa 1878, for transmitting a daily time signal from the U.S. Naval Observatory to other U.S. cities. Noon was also announced to Washingtonians by the drop of a ball from the observatory's telescope dome (inset). Credit: U.S. Naval Observatory Library
Found in: Science & Society

Follow Us
blogs & columns
multimedia
Not to miss
bookshelf