60 Thinqs not qenerallii Known. 



i7 y ./ 



suitable reflections or refractions. Hence we obtain a most 

 simple method of discovering the nature of the sun at a distance 

 of forty millions of leagues. For if the light emanating from 

 the margin of the sun, arid radiating from the solar substance 

 at an acute angle, reach us without having experienced any 

 sensible reflections or refractions in its passage to the earth, 

 and if it offer traces of polarisation, the sun must be a solid or 

 a liquid body. But if, on the contrary, the light emanating 

 from the sun's margin give no indications of polarisation, the 

 incandescent portion of the sun must be gaseous. It is by means 

 of such a methodical sequence of observations that we may 

 acquire exact ideas regarding the physical constitution of the 

 sun. Note to Humboldt's Cosmos, vol. iii. 



STRUCTURE OF THE LUMINOUS DISC OF THE SUN. 



The extraordinary structure of the fully luminous Disc of 

 the Sun, as seen through Sir James South's great achromatic, 

 in a drawing made by Mr. Grwilt, resembles compressed curd, 

 or white almond -soap, or a mass of asbestos fibres, lying in 

 a quaquaversus direction, and compressed into a solid mass. 

 There can be no illusion in this phenomenon ; it is seen by 

 every person with good vision, and on every part of the sun's 

 luminous surface or envelope, which is thus shown to be not 

 & flame, but a soft solid or thick fluid, maintained in an incan- 

 descent state by subjacent heat, capable of being disturbed by 

 differences of temperature, and broken up as we see it when 

 the sun is covered with spots or openings in the luminous 

 matter. North- British Review, No. 16. 



Copernicus named the sun the lantern of the world (lucerna irnindi}; 

 and Theon of Smyrna called it the heart of the universe. The mass of 

 the sun is, according to Encke's calculation of Sabine's pendulum for- 

 mula, 359,551 times that of the earth, or 355,499 times that of the earth 

 and moon together ; whence the density of the sun is only about (or 

 more accurately 0'252) that of the earth. The volume of the sun is 

 600 times greater, and its mass, according to Galle, 738 times greater, 

 than that of all the planets combined. It may assist the mind in con- 

 ceiving a sensuous image of the magnitude of the sun, if we remember 

 that if the solar sphere were entirely hollowed out, and the earth placed 

 in its centre, there would still be room enough for the moon to describe 

 its orbit, even if the radius of the latter were increased 160,000 geo- 

 graphical miles. A railway-engine, moving at the rate of thirty miles 

 an hour, would require 360 years to travel from the earth to the sun. 

 The diameter of the sun is rather more than one hundred and eleven 

 times the diameter of the earth. Therefore the volume or bulk of the 

 sun must be nearly one million four hundred thousand times that of the 

 earth. Lastly, if all the bodies composing the solar system were formed 

 into one globe, it would be only about the five-hundredth part of the 

 size of the sun. 



