Despite one or two amateur attempts at creating a separate image for each eye, it was 1838 lecture to Royal Society in London by Sir Charles Wheatstone that truly took world by storm.
I have reprinted this work, complete with original images, at http://www.wehner.org/3d/first/ .
What reader will discover is astonishing detail with which Professor Wheatstone - as he then was - approaches every nuance of minutiae of visual perception.
With almost every aspect of phenomenon of stereopsis accurately defined, Victorians could rush ahead - particularly after arrival of photography - with production of images that convey depth.
That human mind does not just play eyes over object to measure depth, but can appreciate geometrical form "at a glance" was proven by a simple and ingenious experiment by Wheatstone.
However, an aspect that has been largely overlooked is importance of SHORT-TERM MEMORY for further enhancement of stereoscopic impression.
There is at core of brain a sensory area known as "Limbic System" that gathers impressions from all input data and merges them into an overall "feeling".
Thus, sound, smell, visual appearance, mechanical feel and other facets of an object are all combined in limbic system for its overall cognition. The result might be called a NOUN.
Similarly, when one decides to walk one does not consciously activate every muscle in its correct sequence. Instead, one builds up a REPERTOIRE of movements - a LEG DRIVER in computer parlance - and learned reflex of walking need only be triggered. This reflex "software" resides in cerebellum.
Gnosisceptors (sensory nerves) feed back feeling of walking to limbic system. Thus, when our minds decide to walk, when our eyes see movement and our balancing mechanism records motion, and gnosisceptors in legs confirm leg action, we "feel" walking in our limbic system. Our walking is a VERB.
So verbs and nouns of our perception are created in brain.
It is an inevitable consequence of evolution that those animals that need precise close-up stereopsis have eyes that point forwards. Think of preying animals, lions and tigers.
Those animals that need a wider field of view - such as birds - have eyes on sides of head. Think of herd animals like horses and antelope.