about 120 million rods are in the human eye.
about 120 million rods are in the human eye.
how many rods are in the human eye?
about 120 million
rods, which are extremely abundant (about 120 million), are in the periphery of the human retina. rods respond only to faint levels of light and are very light sensitive, therefore, completely useless in daylight. cones have three types of pigments with different color sensitivities, whereas rods only have one and so are achromatic (colorless). because of the distribution of rods and cones in the human eye, people have good color vision near the fovea (where cones are) but not in the periphery (where the rods are).
monochromacy
setting up a machine involved building a suitable network of linkages. according to one user, this was achieved by locating above the reading block, in contact with the tops of the matrix pins, a removable y-shaped 'connection box' (equivalent to the hollerith plug board) which was hard-wired to the job. the box had at the base as many rods as were needed to read the positions within the used data fields, so that, when forced down, appropriate features of the machine - printheads, counters or control links were physically set as a reaction to the moving tops of the connecting box rods. thus while many connection wires were straight-through, some sensed holes needed to allow multiple actuation, while some multiple code-punching needed to be combined to achieve a single purpose. designing the system, including setting up the tabulator, was the sales engineers job, while soldering the 'conn-box' forest of cranked rods to meet the design requirement was down to the skill of the powers engineer who was thus the doyen of the machine room.
powers-samas