2 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



William Thomson's very remarkable essay on the age of the 

 sun's heat (MacmiUari's Magazine, March, 1862), in which it 

 is shown that the sun's radiation amounts to about 7000 

 horse-power for each square foot of its surface, and that coal 

 burning at the rate of half a pound per second produces al- 

 most the same result. But Rankine has estimated that in 

 the furnace of an ordinary locomotive coal is consumed at 

 the rate of one pound per square foot of grate surface in from 

 30 to 90 seconds. Hence the force expended in radiation 

 from a square foot of the sun's surface is only from 15 to 45 

 times greater than that developed from an equal surface of 

 coal burning in the furnace of a locomotive ; and as the in- 

 crease of radiation is much more rapid than that of tempera- 

 ture, it would require an increase of temperature of less than 

 1000 Fahr. to make the radiation from the coals the same as 

 that from an equal area of the sun's surface. 



Sainte-Claire Deville and Edmond Becquerel entirely con- 

 curred in the views expressed by M. Vicaire. M. Fizeau re- 

 marked that these conclusions were in perfect harmony with 

 photometrical experiments, which show that the intensity of 

 the Drummond light is 56 times less than that of the electric 

 light, which latter is only 2-J times less intense than sunlight 

 itself. It therefore follows that the two last-named sources 

 of light are in all respects comparable, and we must admit 

 that their temperatures can not differ so excessively as is in- 

 dicated by many of the recent estimates of the heat of the 

 solar surface. 6 B. 



faye's view of the fhysical condition of the sun. 



The 3Iechanics i Magazine gives a summary of an interest- 

 ing paper by Mr. Faye upon the physical condition of the sun, 

 deduced from the observation of the solar spots made by 

 Carrington. This is expressed in the following propositions: 



1. That Zollner's theory, which views the sun as a solid 

 body covered with a layer of incandescent liquid, is entirely 

 improbable, and, indeed, impossible. 2. The speed of rotation 

 of any point whatever on the sun's surface is always expressed 

 by one and the same formula. 3. There do not exist on the 

 sun's surface any sensible currents which are at all analogous 

 to the " trade winds." 4. The absolute absence of currents 

 is only explicable by the presence every where of ascending 



