12 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



the atmosphere. In general, when we look at the solar disk, 

 we perceive that it has' a nearly uniform brightness, except- 

 ing, of course, the trains of spots that are scattered across it 

 in zones parallel to the solar equator, and the irregular white 

 patches called facula?. A more attentive examination shows 

 that the surface of the sun, even near the centre where neither 

 faculae nor spots are visible, is not absolutely uniform, but is 

 made up of fleecy clouds, whose outlines are all but indis- 

 tinguishable. Under more painstaking scrutiny, numerous 

 faint dots on the white ground were observed, producing the 

 impression of a moss-like structure in the clouds. With high 

 magnifying powers, used in favorable moments, the surface 

 of any one of the fleecy patches is resolved into a congeries 

 of small, intensely bright bodies, irregularly distributed, 

 which seem to be suspended in a comparatively dark medium, 

 and whose definiteness of size or outline, although not abso- 

 lute, is yet striking by contrast with the vagueness of the 

 cloud forms seen before, which vagueness we now perceive to 

 be due to their aggregation. The dots referred to are con- 



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siderable openings, caused by the absence of the white nod- 

 ules at certain points, and the consequent exposure of the gray 

 medium which forms a general background. These dots or 

 openings have been called pores. The diameter of the more 

 conspicuous varies from two to four seconds. The bright 

 nodules are neither uniform in shape nor in brightness. The 

 outline is irregular, but, on the whole, affects an elongated or 

 oval contour. Mr. Stone has called them rice grains, a term 



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appropriate only when we view them with a telescope of 

 three or four inches' aperture. In moments of rarest definition, 

 Professor Langley has been able to resolve these rice grains into 

 minuter components, which he calls granules, whose diameter 

 can hardly equal 0.3". From these granules comes by far 

 the largest portion of the sun's light. Their number varies 

 widely ; there being commonly from three to ten in each rice 

 grain, and their area is such that the properly luminous area 

 of the sun is less than one fifth of the whole solar surface. 

 We must, then, greatly increase our received estimates of the 

 intensity of the action to which solar light, heat, and actinism 

 are due. 



With reference to the study of the solar spots, properly so- 

 called, Professor Langley shows that in the penumbra there are 



