English: Stereoscopic photograph of two types of rope-bridge across the River Jhelum at Uri in Jammu and Kashmir, taken by James Ricalton in c. 1903, from The Underwood Travel Library: Stereoscopic Views of India. This image is described by Ricalton in 'India Through the Stereoscope' (1907), "Among the Himalayas several kinds of primitive bridges are in use; there are two kinds here before us now. The one we see in use consists of a single strand of raw-hide rope made fast to either shore by an anchorage of stone, and then elevated and supported by a few rude sticks. A saddle or carrier is made from the crotch of a tree inverted over the rope; a loop of rope is attached to each pending arm of the saddle; through these loops the legs of the passenger are thrust, while his hands clutch the projecting top of the saddle. A small pull cord extends from the saddle to a bridge-tender on each side of the river...those huge, ragged strands suspended cross to the right and up the river...are the remains of a former bridge...formed by two heavy cables of twigs or withes, bound and interlaced to a thickness of about five inches; those were held apart and supported by transverse sticks which can be seen still dangling from the unbroken cable. For the foot-way, sections of split timber or bamboo were placed at stepping distances on the cables." This is one of a series of 100 photographs, designed to be viewed through a special binocular viewer, producing a 3D effect. The series was sold together with a book of descriptions and a map with precise locations to enable the 'traveller' to imagine that he was touring around India. Stereoscopic cameras, those with two lenses and the ability to take two photographs at the same time, were introduced in the mid 19th century and revolutionised photography. They cut down exposure time and thus allowed for some movement in the image without blurring as subjects were not required to sit for long periods to produce sharp results.