For a long time, the second was defined as a fraction of the day, and later of the year. But Earth's rotation is not perfectly regular. Since 1967, the second has been based on an atomic phenomenon: 9,192,631,770 oscillations of the radiation emitted by a caesium-133 atom during a specific transition. The most precise experimental clocks today would drift by just one second over billions of years.
In 1843, inventor Alexander Bain patented a way to send images over telegraph wires using synchronized pendulums. By the 1860s, a commercial fax service was already linking cities. The telephone wasn't patented until 1876, more than three decades after that first fax patent. The fax is really a child of the telegraph age.
On 8 October 1958, in Stockholm, 43-year-old Arne Larsson received the very first implanted pacemaker. The device, designed by engineer Rune Elmqvist and implanted by surgeon Åke Senning, worked for only a few hours and had to be replaced. Larsson went on to receive more than twenty pacemakers in his lifetime. He died in 2001 aged 86, outliving both the engineer and the surgeon.