S. P. Langley—Minute structure of the Solar Photosphere. 95 
intrinsic brilliancy as those measured, are demonstrably not 
over ”-03 in diameter, and of course, apart from their irradia- 
The course of this examination has, it is hoped, made it 
plain, that if the photosphere were really composed of spindle- 
shaped bodies about one hundred miles wide by one thousand 
long (nearly 0-2 by 2”,—the dimensions of Mr. Nasmyth’s 
“willow-leaves”), they would not have escaped notice. Yet 
while, with a confidence justified by the micrometrie measure- 
ments of so much smaller bodiés, we may say that Mr. Nas- 
myth was misled in a matter of detail, we should remember 
that he appears to have been the first to distinctly call atten- 
fon to the singular individuality of the minute components of 
the photosphere, and this seems in fairness to entitle him to 
the credit of an important discovery, with which his name 
should remain associated 
circumstances we have no exact analogy in our own meteor- 
ology.* 
Let us now consider the filaments as indices of the character 
of the gaseous circulation of the sun as we see it in the spots. 
We find about F , and G, two considerable masses of the pho- 
* In the recen: axwell and others, as to the viscosity of 
Gases under high pte aaa a is known of the diffusion rates of 
and vapors, i i tions as to the possible 
explanation of some of their peculiarities, the consideration of which, however, 
not form a part of our present subject. _ 
