h picture of our natural
double view, would defy any human skill to reproduce them exactly.
And just here comes in the photograph to meet the difficulty. A first
picture of an object is taken,--then the instrument is moved a couple
of inches or a little more, the distance between the human eyes, and a
second picture is taken. Better than this, two pictures are taken at
once in a double camera.
We were just now stereographed, ourselves, at a moment's warning, as
if we were fugitives from justice. A skeleton shape, of about a man's
height, its head covered with a black veil, glided across the floor,
faced us, lifted its veil, and took a preliminary look. When we had
grown sufficiently rigid in our attitude of studied ease, and got
our umbrella into a position of thoughtful carelessness, and put our
features with much effort into an unconstrained aspect of cheerfulness
tempered with dignity, of manly firmness blended with womanly
sensibility, of courtesy, as much as to imply,--"You honor me, Sir,"
toned or sized, as one may say, with something of the self-assertion of
a human soul which reflects proudly, "I am superior to all this,"--when,
I say, we were all right, the spectral Mokanna dropped his long veil,
and his waiting-slave put a sensitive tablet under its folds. The veil
was then again lifted, and the two great glassy eyes stared at us once
more for some thirty seconds. The veil then dropped again; but in the
mean time, the shrouded sorcerer had stolen our double image; we were
immortal. Posterity might thenceforth inspect us, (if not otherwise
engaged,) not as a surface only, but in all our dimensions as an
undisputed _solid_ man of Boston.
2. We have now obtained the double-eyed or twin pictures, or
STEREOGRAPH, if we may coin a name. But the pictures are two, and we
want to slide them into each other, so to speak, as in natural vision,
that we may see them as one. How shall we make one picture out of two,
the corresponding parts of which are separated by a distance of two or
three inches?
We can do this in two ways. First, by _squinting_ as we look at them.
But this is tedious, painful, and to some impossible, or at least very
difficult. We shall find it much easier to look through a couple of
glasses that _squint for us_. If at the same time they _magnify_ the
two pictures, we gain just so much in the distinctness of the picture,
which, if the figures on the slide are small, is a great advantage. One
of t
|