125 



SCIENTIFIC SIDE-LIGHTS 



Conservation 

 Constituent! 



than one which is unstable, one month pos- 

 sessing 500 bacteria per c. c. and another 

 month 5,000. NEWMAN Bacteria, ch. 2, p. 

 51. (G. P. P., 1899.) 



617. CONSTANCY OF LAWS OF NA- 

 TURE Adapts Universe for Rational Beings. 

 -Unless the laws of Nature were constant, 

 in so far as our experience extends, we could 

 have no certain basis either for science or 

 for practical life. All would be capricious 

 and uncertain, and we could calculate on 

 nothing. Law thus adapts the universe to 

 be the residence of rational beings, and noth- 

 ing else could. DAWSON Facts and Fancies 

 in Modern Science, lect. 1, p. 39. (A. B. 

 P. S.) 



618. 



Altitude Determined 



by Boiling-point. As we ascend a moun- 

 tain, the pressure of the atmosphere above 

 us diminishes, and the boiling-point is cor- 

 respondingly lowered. On an August morn- 

 ing in 1859 I found the temperature of boil- 

 ing water on the summit of Mont Blanc to 

 be 184.95 F.; that is, about twenty-seven 

 degrees lower than the boiling-point at the 

 sea-level. On August 3, 1858, the tempera- 

 ture of boiling water on the summit of the 

 Finsteraarhorn was 187 F. On August 10, 

 1858, the boiling-point on the summit of 

 Monte Rosa was 184.92 F. The boiling- 

 point on Monte Rosa is shown by these ob- 

 servations to be almost the same as it was 

 found to be on Mont Blanc, tho the latter 

 exceeds the former in height by 500 feet. 

 The fluctuations of the barometer are, how- 

 ever, quite sufficient to account for this 

 anomaly. The lowering of the boiling-point is 

 about 1 F. for every 590 feet of elevation; 

 and from the temperature at which water 

 boils we may approximately infer the 

 height. TYNDALL Heat a Mode of Motion, 

 lect. 6, p. 100. (A., 1900.) 



619. CONSTANCY OF VISION-^lw- 



cient Same as Modern Six or Seven Stars 

 Seen in the Pleiades. However diversified 

 the power of vision may be in different per- 

 sons, there is nevertheless a certain average 

 of organic capacity, which was the same 

 among former generations, as, for instance, 

 the Greeks and Romans, as at the present 

 day. The Pleiades prove that several thou- 

 sand years ago, even as now, stars which 

 astronomers regard as of the seventh mag- 

 nitude were invisible to the naked eye of 

 average visual power. The group of the 

 Pleiades consists of one star of the third 

 magnitude, Alcyone; of two of the fourth, 

 Electra and Atlas; of three of the fifth, 

 Merope, Maia, and Taygeta ; of two between 

 the sixth and the seventh magnitudes, 

 Pleione and Celseno; of one between the sev- 

 enth and the eighth, Asterope ; and of many 

 very minute telescopic stars. I make use of 

 the nomenclature and order of succession at 

 present adopted, as the same names were 

 among the ancients in part applied to other 

 stars. The six first-named stars of the 



third, fourth, and fifth magnitudes were the 

 only ones which could be readily distin- 

 guished. Of these Ovid says (Fast., iv, 

 170) : 



" Quae septem dici, sex tamen esse solent." 

 [Which are called seven, but are usually 



seen as six.] 



One of the daughters of Atlas, Merope, the 

 only one who was wedded to a mortal, was 

 said to have veiled herself for very shame, 

 or even to have wholly disappeared. This is 

 probably the star of about the seventh mag- 

 nitude which we call Celseno; for Hippar- 

 chus, in his commentary on Aratus, observes 

 that on clear moonless nights seven stars 

 may actually be seen. Celaeno, therefore, 

 must have been seen, for Pleione, which is 

 of equal brightness, is too near to Atlas, a 

 star of the fourth magnitude. HUMBOLDT 

 Cosmos, vol. iii, p. 48. (H., 1897.) 



62O. 



The Same Constel- 



lations Recognized by Rudest Nations. 

 Amid the innumerable multitude of great 

 and small stars, which seem scattered, as it 

 were by chance, throughout the vault of 

 heaven, even the rudest nations separate 

 single (and almost invariably the same) 

 groups, among which certain bright stars 

 catch the observer's eye, either by their 

 proximity to each other, their juxtaposition, 

 or, in some cases, by a kind of isolation. 

 This fact has been confirmed by recent and 

 careful examinations of several of the lan- 

 guages of so-called savage tribes. Such 

 groups excite a vague sense of the mutual 

 relation ot parts, ?^d have thus led to their 

 receiving names which, altho varying among 

 different races, were generally derived from 

 organic terrestrial objects. Amid the forms 

 with which fancy animated the waste and 

 silent vault of heaven, the earliest groups 

 thus distinguished were the seven-starred 

 Pleiades, the seven stars of the Great Bear, 

 subsequently (on account of the repetition 

 of the same form) the constellation of the 

 Lesser Bear, the belt of Orion (Jacob's 

 staff), Cassiopeia, the Swan, the Scorpion, 

 the Southern Cross (owing to the striking 

 difference in its direction before and after 

 its culmination), the Southern Crown, the 

 Feet of the Centaur (the Twins, as it were, 

 of the southern hemisphere), etc. HUM- 

 BOLDT Cosmos, vol. iii, p. 117. (H., 1897.) 



621. CONSTITUENTS OF THE SUN 



Rays of Nucleus and Photosphere Con- 

 flict Fraunhofer's Lines. The sun, accord- 

 ing to Kirchhoff, consists of a central orb, 

 molten or solid, of exceeding brightness, 

 which emits all kinds of rays, and would 

 therefore, if unhindered, give a continuous 

 spectrum. The radiation from the nucleus, 

 however, has to pass through the photo- 

 sphere, and this vaporous envelope cuts off 

 those particular rays of the nucleus which 

 it can itself emit the lines of Fraunhofer 

 marking the position of the failing rays. 

 Could we abolish the central orb, and obtain 



