ASTRONOMY: E. E. BARNARD 393 
ently of a similar nature to the remarkable dark 'lanes' shown in my 
photographs of a region in Taurus. {See Astro phys. J., 25, 218, 1907). 
There are two very small dark spots near and south of the west end of 
the dark marking. 
The accompanying plate is from a photograph which was taken by 
me on October 1, 1910, with the 10-inch Bruce telescope of the Yerkes 
Observatory, with an exposure of 6 h. 2 m. I had previously taken a 
photograph of this part of the sky on September 30, 1910, with an ex- 
posure of 5 h. 5 m. which verifies the above in all particulars. 
NORTH 
DARK OBJECT IN CEPHEUS {a = 2Q^ 48™, 5 = +60°) 
Scale: l°=41mm. 
There are two possible explanations of this object: 
(1) That it is an opening in a widely diffused nebulous stratum. 
(2) That it is an opaque, non-luminous object projected against 
space, which is itself luminous. 
From this object and those in Taurus, I get the impression that the 
interstellar spaces (or possibly the regions beyond the stars), perhaps 
covering the entire heavens, are suffused with a feeble nebulosity that, 
with very prolonged exposures, affects the photographic plate; and that 
such phenomena (as the present one) are due to the projection upon 
this background of nearer, dark, opaque objects. If not this, then they 
