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352 - On. the Refraction of Light. 
In looking through the Jong aperture, placed at a short distance 
from the eye, dark and bright lines, such as are seen bordering shad- 
ows and supposed to be deflected from bodies, will appear running 
parallel to the fissure. Having closed one eye, if we apply the long 
aperture in such a manner to the other that the pupil shall be nearly 
covered, and then direct the glance to a luminous object, it will ap- 
pear beautifully bordered with chromatic light. The uniform devel- 
opment of color along the edges of bodies, led to some experiments, 
instituted for the purpose of examining, under various circumstanees, 
this phenomenon. From among them I select the following as being 
curious and anomalotis: close one eye, and with the other look stead- 
fastly at any luminous object, as the flame of a candle or an illuma- 
ted window; then move an opaque body (for example the finger,) 
gradually across the eye; and when the pupil is nearly covered, the 
candle flame will appear to glow with the primitive colors. The 
moon viewed in this manner presents a beautiful and splendid spec- 
tacle. - It is remarkable in this experiment that the colors, supposed 
to be compound, viz. the orange, green and indigo, are more copi- 
~ ously and distinctly developed than the primary ones. © Whether the 
opaque body be black or white, the same unaccountable appearance 
will be produced. ‘ ot FTE. 
When the sun is viewed through a puncture, the transmitted white 
light is resolved into its elementary. hues, and the colors are seen e™- 
anating separately from thé sun... ae 
If we apply the long aperture to the eye, and hold aneed 
distance behind it, it will form a curve, which being gradually brought - 
closer to the eye, will enlarge into’ the seeming shadow before spo- 
ken of; but if we place behind the long aperture a broader body, 
as the flat side of a penknife blade, it will appear cut on either side 
by a semicircle, thus describing a space between two circles. In 
passing through a small circular aperture, the image of a candle 
_ flame received on a white surface, will be found inverted, and if the 
white surface. be held at some distance, the image will be exceed- 
‘ingly magnified, asin the case of its transmission through a double 
convex lens. In other instances the small aperture displays the prop 
erties of a double concave glass, as in giving distinctness and achro- 
macy to telescopic images. When the image of a candle flame Is 
transmitted through a long incision in the lead, it will he multiplied 
and present the appearance of a row of lights all inverted. If a 
plate of lead having many punctures be held close to 2 candle flame; 
