62 



DISCOVERY 



Diocletian, and in more recent experiences, in all of 

 which there was regulation of prices. Khammurabi's 

 law was evidently a compromising of two different 

 systems, the city and the pastoral life. Diocletian's 

 law was at the junction of free outstanding peoples 

 reacting on Roman life, influenced also by the degrada- 

 tion of currency. Our experience in the middle ages 

 was where city life became centralised, and could not 

 provide its own food, so that the separate country life 

 interacted on it irregularly. Our recent war experience is 

 where the free flow of trade was interrupted, and foreign 

 supplies were intermittent and not subject to free 

 supply and demand, thus giving back to the interaction 

 of two separate systems, external and internal. Such 

 seems to be the cause of price-regulation ; but it can 

 only be a very brief phase, just so long as supply is 

 automatic, for it quickly destroys supply and suppresses 

 demand. 



Another question to be answered ; Are we to regard 

 the infiltration of a people into another country as 

 preparatory to general invasion ? The fall of the 

 first prehistoric civilisation was long preceded by the 

 infiltration of the second people. A similar change 

 preceded the fall of the second people ; also the Syrian 

 break-up of the Vlth dynasty, the Hyksos invasion, 

 the Greek occupation, and the Arab conquest of 

 Egypt, the Germanic conquest of Rome, the Saxon 

 settlement of England, and the Danish occupation of 

 England culminating in the Normans. A migration- 

 conquest (in contrast to a political conquest) appears 

 to be usually preceded by centuries of individual 

 entry and settlement. Let us beware of systematic 

 infiltration by other nations. 



Comparative history is necessary for us to realise 

 that no civilisation is influenced by an inferior, but only 

 by a civilisation which is equal or superior in some 

 respect. We see, in the past, Elam strongly dominat- 

 ing in Mesopotamia and in Egypt ; Syria permeating 

 Egypt in the XVIIIth dynasty ; Perso-Roman work 

 modifying China in the Han period ; China dominating 

 Japanese life ; Gothic art ruling even in the Forum of 

 Rome under Theodoric ^ ; Japan influencing European 

 work now. In each case there are qualities in the new 

 influence which are superior to — or lacking in — the 

 existing system. 



As in organic life we realise more and more how 

 essential it is to study the life-cycle of each organism, 

 if we would understand its real conditions, so in the 

 biology of civilisations we must study their life-c^'cle 

 of birth, growth, and decay, if we would know the 

 cause of changes, and the meaning of the present world 

 around us. This is history. 



' Theodoric, leader of the Western Goths, conquered Italy, 

 A.D. 489. — Ed. 



Our Neighbour Worlds 



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

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



II. THE GIANT PLANETS 



The four giant planets may be conveniently divided 

 into two sub-classes. The first is composed of Jupiter 

 and Saturn, by far the largest bodies in the Solar 

 System, with the single exception of the Sun — planets 

 which were first recognised as such in prehistoric 

 times ; while the second group consists of Uranus and 

 Neptune, which, though undoubtedly belonging to the 

 category of giant planets, are considerably smaller, 

 and whose existence was unknown till less than a 

 hundred and fifty years ago. 



The study of Jupiter dates from the time of Galileo, 

 whose most striking telescopic discovery was that of 

 the four large satellites of the giant planet in January 

 1610. His telescope was not powerful enough, however, 

 to reveal any markings on the Jovian disc, and it was 

 not till 1630 that Zucchi, an Italian observer otherwise 

 unknown to fame, first noticed the parallel lines since 

 known as the belts of Jupiter. Thirty-four years 

 later a still more significant discovery was made, when 

 the English astronomer, Hooke, detected a small spot 

 which he perceived to be in motion. His suspicion 

 that this indicated a rotation of Jupiter on its axis was 

 confirmed in 1665 by Cassihi, who determined the 

 period as 9 hours 55 minutes, which, like most of 

 Cassini's determinations, was a remarkable approxi- 

 mation to the truth. 



The first interpretation of the Jovian markings was 

 put forward by Sir William Herschel in 1781. In a 

 paper on the rotation of the planets on their axes he 

 threw out the hint that the belts represented currents 

 in Jupiter's atmosphere, somewhat analogous to the 

 terrestrial trade-winds. This view was in harmony 

 with Herschel's general conception of planetary con- 

 ditions. To him it was an axiom that our neighbour 

 worlds were " richly stored with inhabitants," and thus 

 he was led to interpret his observations of Jupiter in 

 the light of the hypothesis that the great planet was 

 simply an immensely larger edition of the Earth. 

 During the greater part of the nineteenth century this 

 view of Jupiter prevailed, and was accepted by most of 

 the popular writers on astronomy. J. P. Nichol, for 

 instance, interpreted the spots as mountains, in keeping 

 with the current view, which was held also by Sir John 

 Herschel. 



There had been, it is true, doubts as to the validity 

 of the parallel drawn between Jupiter and the Earth. 

 Bufton in 1778, and Kant in 1785 — neither of them 

 astronomers — had suggested that Jupiter was stifl in 

 a state of great internal heat, and the same suggestion 



