



SCIENTIFIC SIDE-LIGHTS 



Assumption-* 

 Astronomy 



the altitude which the pole star of that day, 

 a Draconis, attained at its lower transit 

 across the meridian. FLAMMARION Popular 

 Astronomy, p. 39. (A.) 



255. ASTRONOMY IN CHINA More 



Fitly Termed Astrology Calculations 

 Grossly Erroneous. Arguments in support 

 of the presumed knowledge of the Chinese 

 regarding navigation are often based on 

 their alleged attainments in astronomy; 

 for they have undoubtedly studied the phe- 

 nomena dealt with by that science since 

 time immemorial. But their calculations 

 of eclipses have been found erroneous; and 

 the astronomer Cassini, in examining an 

 observation of one winter solstice very cele- 

 brated in their annals, discovered therein 

 an error of no less than 487 years. They 

 are rather astrologers than astronomers, 

 and their tribunal of mathematics, exist- 

 ing, as it has, for centuries, has found its 

 chief occupation in indicating to the gov- 

 ernment fortunate days for national enter- 

 prises or ceremonials rather than in gather- 

 ing the results of observation. In brief, 

 their system of astronomy is rigidity itself, 

 and if its predictions fail they argue that 

 the fault is not in themselves, but in their 

 stars, and settle the matter by deferring 

 further prophecy until after the event. 

 PARK BENJAMIN Intellectual Rise in Elec- 

 tricity, ch. 3, p. 79. (J. W., 1898.) 



256. ASTRONOMY MADE POSSIBLE 

 BY MATHEMATICS Ancient Thinkers Pre- 

 pared the Way for Modern Discoverers 

 Reason Directs the Telescope. The age of 

 the Ptolemies was a most brilliant epoch 

 in the prosecution of mathematical inves- 

 tigations. In the same century there ap- 

 peared Euclid, the creator of mathematics 

 as a science; Apollonius of Perga, and 

 Archimedes, who visited Egypt, and was 

 connected through Conon with the school of. 

 Alexandria. The long period of time which 

 leads from the so-called geometrical anal- 

 ysis of Plato ... to the age of Kep- 

 ler and Tycho Brahe, Euler and Clairaut, 

 D'Alembert and Laplace, is marked by a 

 series of mathematical discoveries without 

 which the laws of the motion of the 

 heavenly bodies and their mutual relations 

 in the regions of space would not have been 

 revealed to mankind. While the telescope 

 serves as a means of penetrating space, and 

 of bringing its remotest regions nearer to 

 us, mathematics, by inductive reasoning, 

 have led us onward to the remotest regions 

 of heaven, and brought a portion of them 

 within the range of our possession; nay, in 

 our own times so propitious to extension 

 of knowledge the application of all the 

 elements yielded by the present condition 

 of astronomy has even revealed to the in- 

 tellectual eye a heavenly body, and assigned 

 to it its place, orbit, and mass, before a 

 single telescope had been directed toward it. 

 HUMBOLDT Cosmos, vol. ii, pt. ii, p. 179. 

 (H., 1897.) 



257. ASTRONOMY OF ANTIQUITY 



Substitute for the Telescope Lensless 

 Tubes Excluded Diffused Light. We find, 

 without including the epoch of the Chal- 

 deans, Egyptians, and Chinese, that more 

 than nineteen centuries intervened between 

 the age of Timochares and Aristillus and 

 the discoveries of Galileo, during which 

 period the position and course of the stars 

 were observed by the eye alone, unaided by 

 instruments. . . . We are astonished 

 that Hipparchus and Ptolemy should have 

 been so well acquainted with the precession 

 of the equinoxes, the complicated move- 

 ments of the planets, the two principal 

 inequalities of the moon, and the position 

 of the stars; that Copernicus should have 

 had so great a knowledge of the true sys- 

 tem of the universe; and that Tycho 

 Brahe should have been so familiar with the 

 methods of practical astronomy before the 

 discovery of the telescope. Long tubes, 

 which were certainly employed by Arabian 

 astronomers, and very probably also by the 

 Greeks and Romans, may indeed, in some 

 degree, have increased the exactness of the 

 observations by causing the object to be 

 seen through diopters or slits. Abul-Has- 

 san speaks very distinctly of tubes, to the 

 extremities of which ocular and object 

 diopters were attached; and instruments 

 so constructed were used in the observatory 

 founded by Hulagu at Meragha. If stars be 

 more easily discovered during twilight by 

 means of tubes, and if a star be sooner re- 

 vealed to the naked eye through a tube than 

 without it, the reason lies, as Arago has al- 

 ready observed, in the circumstance that 

 the tube conceals a great portion of the dis- 

 turbing light diffused in the atmospheric 

 strata between the star and the eye applied 

 to the tube. In like manner, the tube pre- 

 vents the lateral impression of the faint 

 light which the particles of air receive at 

 night from all the other stars in the firma- 

 ment. The intensity of the image and the 

 size of the star are apparently augmented. 

 In a frequently emendated and much con- 

 tested passage of Strabo, in which mention 

 is made of looking through tubes, this " en- 

 larged form of the stars " is expressly 

 mentioned, and is erroneously ascribed to 

 refraction. HUMBOLDT Cosmos, vol. iii, p. 

 42. (H., 1897.) 



258. ASTRONOMY OF THE EARLY 

 WORLD A Slow Growth through Protracted 

 Observation. Wherever steppes, grassy 

 plains, or sandy wastes present a far-ex- 

 tended horizon, those constellations whose 

 rising or setting corresponds with the busy 

 seasons and requirements of pastoral and 

 agricultural life have become the subject 

 of attentive consideration, and have gradu- 

 ally led to a symbolizing connection of 

 ideas. Men thus became familiarized with 

 the aspect of the heavens before the de- 

 velopment of measuring astronomy. They 

 soon perceived that besides the daily move- 

 ment from east to west, which is common 



