when we do not intentionally create a difficult case) view that object. That is 
not all the same. For we can also look aimlessly with one eye at something, 
without paying attention to it. If, however, we do the latter, then we usually 
make use of another property of our eye at the same time, viz. accommo- 
dation. By this we understand the adjusting of the form of the eyeball and of 
the lens in such a manner, that we see the object *clearly", in other words the 
image is in sharp focus on the retina and especially in its yellow spot. 
Binocular vision or vision with two eyes. 
If we open both eyes and look again at the object which we observed with 
one eye before, then we get the impression that each of our eyes exactly observes 
as we described before. When we look at a definite object it is evident 
that both eyes are directed at the same time at the same object and even at the 
same spot of the object. This is called the convergence of the eye-axes at that 
point. One supposes that convergence is at least partly acquired. Thus 
it is thought that a baby has to learn how to converge. In practice the trouble 
of the baby is that he is not as yet able to fix his attention upon an object. He 
has to learn how to focus; consequently we observe that in his first days the 
baby is squinting or staring and does not really “see” us. However, that has 
nothing to do with inability to converge. The convergence follows automatically 
as soon as the baby knows how to focus and that he has to learn. An experiment 
may make this clear. 
Experiment 1. 
Close one of the eyes and observe a given point. Although we think that 
with one eye no distance can be fixed and the observed point can only be deter- 
mined as lying in the axis of the observing eye, it is evident that, if we close 
that eye and open the other at the same time, the latter, without having obser- 
ved too, is directed to the same point, in other words, with the given eye-axes, 
if attention is paid to a given point, we cannot do anything else but converge. 
as our brain does so automatically. 
Afterwards we shall see why. 
A second wrong opinion is that the feeling of the convergence would be 
decisive for estimating distances. For the moment we know that beyond our will, 
purely by a psychical action, convergence always takes place faultlessly, not- 
withstanding closing one eye. | 
Experiment 2. 
We now take another experiment and shut one of the eyes again. With the 
open eye we observe points at greater and smaller distances. This involves 
altering of convergence beyond our will. This altering of convergence we don't 
perceive; the eye that is closed does hardly move in our feeling. 
What we feel in fact, is the pulling nearer or the gliding further away of the 
gaze of the observing eye. With training we can even attain this effect for different 
distances, without altering the direction of the eye-axes, by thus directing our 
attention respectively to the space behind the point, to the point itself or to the 
space before it; one will then clearly feel a kind of strain and relaxing as when 
breathing. But this feeling we evidently perceive in the viewing eye only.