Who invented Electrocardiograph(EKG)? 

In the early 1950s two scientists, Rosalind Franklin and Maurice Wilkins, studied DNA using x-rays. Franklin produced an x-ray photograph that allowed two other researchers, James Watson and Francis Crick to work out the 3D structure of DNA. The structure of DNA was found to be a double helix.

Benjamin Franklin has long been credited with the invention of bifocal lenses and he was the first to wear bifocal lenses. He did not produce them himself but instead had some optician in London or France make them for him to overcome Presbyopia, a condition that Franklin suffered. He was tired switching between lenses for far and near sightedness. And that resulted in inventing Bifocal Lenses.

Joseph F. Glidden - Father of Barbed Wire.

• Glidden was born in New York in 1812. He invented Barbed Wire in 1873 and was granted the patent on Nov. 24, 1874. After a three year battle over the patent, which he eventually won received a patent for the modern invention in 1874 after he made his own modifications to previous versions.