A conventional lens powerful enough for a lighthouse would be huge and absurdly heavy. In 1822, Augustin Fresnel had the idea of slicing it into concentric rings of prisms: keep the useful curvature, drop the useless glass. The light of a single flame became visible tens of kilometres away. The same principle lives on in spotlights, car lights and overhead projectors.
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.