The South Australian Naturalist. 



Pythagoras maintained that the earth was a sphere revolv- 

 ing around a central "fixed fire," thereby anticipating Galileo. 

 In this theory he was followed by Aristarchus, who taught the 

 heliocentric theory of the solar system. The Ionian philosophers 

 believed in the indestructibility of matter, and that all material 

 things consisted ultimately of a single element ; a theory which 

 has in our days received strong reinforcement from recent experi- 

 ments on the structure of the atom. 



The atomic theory of matter was advanced by Leucippus 

 and Democritus, and was afterwards expounded by Lucretius in 

 his "De Rerum Xatura. " Democritus, too, was credited with 

 a belief, the truth of which Avas established by Galileo, that fall- 

 ing bodies traverse equal distances in equal times. Darwin's 

 theor}^ of natural selection and the nebular hypothesis regarding 

 the origin of our solar system were also among the doctrines he 

 maintained. 



The greatest of the Greek naturalists, Aristotle, in his work 

 "Perizoon Historia" gives some interesting and remarkably 

 accurate details of the structure, anatomy, movements, and em- 

 bryology of a multitude of living creatures; he also compiled 

 an interesting record of the plants. To the best of my know- 

 ledge, many of the statements are accpted by present-da}' 

 naturalists. The Romans mainh' followed the Greeks in their 

 incursions into the realm of natural history, and were chiefly 

 compilers. 



Lucretius, in the "De Rerum Natura," quoted above, made 

 many generalisations which have since been established by 

 observation and experiment — among the rest the germ theory of 

 disease. The elder Pliny in his "Historia Xaturalis" treats 

 of physiology, zoology, botany, and mineralogy ; as evidence of 

 the extent of ancient learning on these points, it may be men- 

 tioned that Pliny quotes from 327 Greeks and 147 Roman 

 writers. His death, through too close an observation of Vesu- 

 vius in eruption, calls to mind a similar devotion in the pursuit 

 of knowledge in the case of Bacon and his refrigeration 

 experiment. 



I must not forget the Latin Wordsworth — the gentle, lov- 

 able author of the JEneid, who combined with an intense love of 

 his native land a tender interest in and deep sympathy with the 

 life and habits of his plants and animals. In his Eclogues he 

 waxes enthusiastic over the power and life of Nature as revealed 

 in the Italian spring — the grace and delicate hues of the wild 

 flowers, the quiet beaut}'^ of green pastures, and the rugged ma- 

 jesty of the cloud-capped mountains. In Virgil's advice to far- 

 mers, given in his Georgies, despite some forgivable mistakes, 



