SKETCH OF JAMES NASMYTH. 123 



medal for his steam hammer, Mr. Nasmyth was given a compli- 

 mentary notice for the lunar pictures and to the Queen and 

 Prince Consort personally. In the course of his astronomical 

 observations he turned to consider the causes of the sun's light 

 and other phenomena of light and heat. In May, 1851, he sent a 

 communication to the Astronomical Society embodying his views 

 that the light of the sun was simply the result of an action on 

 that body of ethereal matter distributed through space unevenly, 

 so that its intensity would vary as the system passed through dif- 

 ferent regions ; that variability in stars might be thus accounted 

 for ; and that our Glacial period was produced by the solar system 

 passing through a region deficient in power of luminosity. Mr. 

 Nasmyth found afterward that these views were paralleled in 

 some features of the theory of the sun enunciated by Dr. Siemens 

 in 1882. He delivered a lecture on the Structure of the Lunar 

 Surfaces before the Edinburgh Philosophical Society in 1858, and 

 in 1874 brought out his book on The Moon considered as a 

 Planet, a World, and a Satellite a work which at once made its 

 mark in selenological literature. He busied himself also with 

 the study of the spots on the sun, and made the novel discovery 

 of the willow-leaved structure of the solar surface, which at- 

 tracted universal attention among astronomers. Sir John Herschel 

 complimented him upon it in his Outlines of Astronomy ; the 

 astronomers at Greenwich made observations that confirmed it ; 

 and Father Secchi was trying to illustrate it by sprinkling rice 

 grains over a blackboard covered with glue at the very moment 

 Nasmyth was introduced to him by their fellow-astronomer Otto 

 von Struve. We should mention, too, in connection with his 

 astronomical studies the paper which he presented to the Royal 

 Astronomical Society about 1851 on the Rotatory Movements of 

 Celestial Bodies, which was suggested by the motion of that kind 

 acquired by water running out of the bottom of a basin. Mr. 

 Nasmyth was also interested in microscopy, and studied twenty- 

 seven forms of infusoria in the water of the Bridgewater Canal ; 

 in photography, and made models of parts of the moon's surface 

 and photographed them ; in the origin of the form of the Pyra- 

 mids, which he attributed to the appearance of the sun's rays 

 streaming through clouds; and to the derivation of the cunei- 

 form characters from the shapes of the impressions made by 

 striking soft clay with the corner of a parallelogram-shaped 

 instrument. He wrote Remarks on Tools and Machinery in 

 Baker's Elements of Mechanics (1858). 



