40 



DISCOVERY 



at Meir. I would, therefore, make bold to suggest that 

 the " new " art which we have been accustomed to 

 consider a special development of the reign of Akhe- 

 naton, resulting from a change in religious beliefs and 

 a consequent abandonment of old conventions, is 

 really due to the fact that when the " heretic king " 

 transferred the capital from Thebes to El-Amama, the 

 local artists were employed to decorate both the 

 temples of the Aton and the palaces, houses, and tomb- 

 chapels, of himself and his courtiers. If this suggestion 

 is correct, then what we have always been taught to 

 regard as a most notable example of realism in the art 

 of El-Amama, namely, the odd-looking figures of the 

 king and his entourage, is, far from being realism, a 

 gross affectation, inherited by the late Eighteenth 

 Dynasty craftsmen of Cusre from their Middle Kingdom 

 predecessors and further developed and exaggerated 

 during the intervening period. 



BIBLIOGR.A.PHY 



Breasted, J. H. : A History oj Egypt, chs. vii-.x. (New York, 



igio. Price 30J.) 

 Blackman, .\. M. : The Rock Tombs of Mcir, Mo\s.i-n\. (Pub- 

 lished by the Egypt Exploration Society, London, 1914- 



1915. Price 25s. per vol.) 

 Davies, N. de G. : The Rock Tombs of El-Amarim. six vols. 



(Published by the Egypt Exploration Society, London, 



1903-1908. Price 24s. per vol.) 

 Klebs, Luise : " Die Reliefs des alten Reiches " (esp. pp. 38 and 

 68 foil.), in Abhandlungen der Heidelberger Akademie des 



Wissenschaften. (London, 1915.) 

 Borchardt, L. : Das Grabdenkmal des Konigs Sahu-re , Band 



II: Die Wandbilder (esp. pi. 17). (Leipzig, 1913) 

 Petrie, W. M. Flinders: Tell-el-Atnarna. (London, 1894. 



Price 21s., out of print.) 

 For good examples of the wooden models placed in the 

 tomb with the mummy and replacing the wall-decorations, 

 see : 

 Garstang, J. : The Burial Customs of Ancient Egypt. (London, 



1907.) 

 Maspero, G. : Art in Egypt, pp. 88-91. (London, 1912. 



Price 6s.) 



Our Neighbour Worlds 



By the Rev. Hector Macpherson, M.A., 

 F.R.A.S., F.R.S.E. 



I. THE DWARF PLANETS 



The Solar System, over which the vast mass of the Sun 

 exercises dominating authority, is composed of bodies 

 of two types — firstly, the planets, which are solid 

 globes of varying volume, mass, and density, which 

 may be called more or less permanent and completed 

 worlds, and which are themselves, with two exceptions, 

 centres of subordinate systems of moons or satellites ; 

 and, secondly, the surplus matter which has been left 

 over in the process of planetary evolution, and which 

 exists in the form of comets, meteors, and asteroids. It 



is true that it has been customary to group the asteroids 

 with the planets, for they have many planetary 

 characteristics, but the discovery in recent years of 

 innumerable small asteroids, some of them only a few 

 miles in diameter, has shown that there is no hard-and- 

 fast dividing line between these bodies and isolated 

 meteors and the clusters of meteors which we call 

 comets. 1 It would seem then that, so far as we know 

 at present, there are only eight bodies in the Solar 

 System which may be correctly designated as planets. 



The planets fall into two main groups — the inner 

 and the outer planets. They may be as accurately 

 designated as dwarf and giant planets. Recent 

 research has familiarised us with the division of the 

 stars into the two groups of giants and dwarfs, and this 

 separation into two types is plainly evident among the 

 planetary bodies composing the Solar System. The 

 giants — Jupiter, Saturn, Uranus, and Neptune — are 

 large diffuse bodies, of great volume and low density, 

 possessing apparently considerable internal heat ; 

 while the dwarfs — the Earth, Venus, Mars, and 

 Mercury — are comparatively small worlds, of consider- 

 able density, and with cool, solid surfaces. 



Planetary astronomy — the study of the surface- 

 features and physical characteristics of the planets and 

 their satellites — has not been characterised by the 

 starthng progress which has marked the development 

 of stellar astronomy in recent years. In the study of 

 the planets, the telescope, unaided by spectroscope 

 or camera, still holds the chief place. In the investiga- 

 tion of the atmospheric envelope of the giant planets, 

 it is true, photography is of some service and the 

 spectroscope is a useful adjunct, but even here visual 

 observation is of the greatest value. And in the case 

 of the dwarfs, where the main object of the observer 

 is the detection and delineation of minute surface 

 detail, the spectroscope and camera play a very sub- 

 sidiary part. 



Mars 



Of the three dwarf planets, which along with our 

 own Earth form the group. Mars has been the most 

 persistently studied, and as a result we are more familiar 

 with its surface than with that of any other body in the 

 universe, except the Moon." For we on the Earth are 

 in a peculiarly favourable position for the observation of 

 Mars ; when the planet approaches the Earth most 

 closely, it is in opposition ^ to the Sun and its disc is 



1 The affinity of asteroids to comets was pointed out by Sir 

 William Hcrschel as long ago as 1802. 



2 In a sense, indeed, we know Mars better than the Moon, as 

 one lunar hemisphere is permanently concealed from our view 

 (since the Moon always keeps the same face turned towards 

 the Earth). 



3 A planet is in " opposition " when it rises at sunset, 

 culminates at midnight, and sets at sunrise. 



