The invention of the flashlight in 1898 is usually linked to the invention of the dry-cell battery. As portable devices, flashlights could not have been powered by the then-prevailing wet-cell technology because wet-cell batteries used a liquid conducting solution such as copper sulfate or ammonium chloride, which made them heavy and required the batteries to be placed on a level surface when in use. So, in 1886, when a German inventor named...Continue Reading