486 



KNOWLEDGE 



[Juke 5, 1885. 



THE FACE OF THE SKY. = • . ' ■ 

 Fkom Junk 5 to June 19. 

 I!v F.R.A.S. 



TIIE spots which coutiniie to appear on the sun are now smaller 

 and scarcely so numerous as they have been ; but as there 

 has quite recently been a beautiful display of them, his surface 

 should be watched on all fine days. Map VI. of "The Stars 

 in their Seasons" depicts the night sky. Twilight persists all 

 night long now. Mercury may be caught as a morning star at the 

 beginning of tlie period to which our notes refer, bnt will scarcely be 

 seen during the remainder of it. Venus is an evening star, and, as 

 she does not set until more than an hour after the sun during the 

 second week of the succeeding fortnight, she may probably be 

 picked up without much difficulty. She is becoming gibbous in the 

 telescope. Jupiter, to be seen to any advantage, must be looked at 

 immediatelythe twilight deepens sufficiently. He sets about half-past 

 eleven .at night by the lOth. Tlie visible phenomena of his satellites 

 are naturally becoming fewer. To-night Satellite I. will be occulted 

 at lUh. -JSm. On the ijth Satellite I. will pass off the pilanet's face 

 .at lOh. :;2m. p.m. On the 13th the same satellite will begin its 

 transit at 10 o'clock at night, and on the 14th reappear frota eclipse 

 at lOh, 37m. lis. p.m. Lastly, on the 16th, Satellite IV. will 

 be eclipsed at lOh. 24m. 57s. VV'e liavc omitted all phenomena 

 not certainly visible. Saturn is absolutely invisible. Uranus 

 remains practically stationary between l3 and y Virginis. The Moon 

 enters her last quarter 48 minutes after midnight to-night ; is new 

 iit 10 h. 421 m. p.m. on the 12th, and enters her first quarter at 

 1 h. 485 m. in the afternoon of the 19th. There are no visible 

 occultations of stars during the next fourteen days. When our 

 notes begin the Moon is in Aquarius, but at 2 o'clock to-morrow 

 morning enters Pisces. She is travelling through this great con- 

 stellation until 7 a.m. on the 9th, the interval between which and 

 3 o'clock the nest afternoon she occupies in crossing the N.AV. 

 corner of Cetus. At the last.n.amed hour she enters Aries, where 

 she continues until 9 p.m. on the 10th, passing then into Taurus. 

 In her journey through Taurus she, at 5 a.m. on the 13th, arrives 

 at the western boundary of the northern strip of Orion, on leaving 

 which, twelve hours later, she enters Gemini. She passes out of 

 Gemini into Cancer at 4 a.m. on the 15th, and quits Cancer for Leo 

 at 3 o'clock the next afternoon (that of the IGth). She descends 

 from Leo into Sextans at 9 p.m. on the 17tb, re-emerging at 

 5 h. 3U m. a.m. on the 18th in Leo. She finally quits Leo at 5 a.m. 

 on the 19th for Virgo. We there leave her. 



THE LUNAR ECLIPSE OF MAECH 30. 



TlIE following extract from a communication of Mr. A. B. Biggs 

 to the Lauyiceston Examiner (a Tasmanian newspaper) of 

 April 1 is not without interest. At the middle of the eclipse its 

 magnitude was 0'88 (the moon's dianieter = l) : — 



" Now, although the eclipse of last night was not total, it was so 

 nearly so as to be of very considerable interest in relation to its 

 appearance in shadow, and I laitl myself out for three hours' 

 observation with special reference to this question. I commenced 

 observing shortly after midnight. Tlie penumbra was then gra- 

 dually creeping over the south-cast limb, though more apparent 

 to the naked eye than in the telescope. The ruggedness of this 

 portion of the moon's surface was at this time distinctly visible 

 even in the profile of the full orb (in the telescope, of course). At 

 Oh. 48m. this ruggedness vanished on the approach of the shadow, 

 and seven minutes later this portion of the outline itself was lost. 

 As the shadow advanced, that part adjacent to each limb ajipeared 

 considerably lighter than the general shadow. At this time, about 

 iifteen degrees of the moon's limb on each side was visible within 

 the shadow, increasing during the middle of the eclipse to about 

 25 degrees ; this portion of the edge appearing as a sharp line of 

 light, gradually fading away into the shadow. With the above ex- 

 ception, all within the shadow was utterly obliterated — lost in the 

 dead slaty tint of the sky. I could not distinguish a single crater 

 after once it was fairly within the shadow. Not the slightest trace 

 of the coppery tint was visible throughout." 



A MATHEMATICAL THEORY OF EVOLUTION. 



THE following is the kernel of Mr. Cave Thomas's lecture on 

 " The Bases of a Science of yKsthetics," which has not only 

 an immediate bearing on the subject treated, but on the entire 

 aspect of scientific thought. In reply to the question, " What were 

 the bases of a science of aesthetics ?" ho said: — " His audience 



were perhaps aware that philosophically it was a well-recognised 

 fact that we know nothing of the external world absoutely per xe, 

 but only phenomenally, or as it appears to us in sense. We had, 

 therefore, to ask ourselves whether there be any common and funda- 

 mental characteristic of those phenomen.a. Speaking more imme- 

 diately with reference to the sense of sight, the knowledge of 

 external existence comes to us by moans of the telegraphy of 

 vibrations, which impresses miniature imagery on the retina. We 

 never even " see things," as we express ourselves, of their actual, 

 but only in their relative proportions ; and when we come 

 to analyse the different kinds of impressions on the sense 

 of sight we tind that they are manifested in the three 

 fundamental modes of consciousness — viz., in space, in time, 

 and in force ; and the important truth to bo deduced 

 from this is that these three modes are alike quantifi.-vble, that is 

 to say the terms more, }css, equal, &c., were producible of the 

 three modes ; differences in the sensations of light, colour, are 

 therefore fundamentally quantitative, or proportional differences, 

 differences in light and shade are also fundacientall}- quantitative, 

 or proportional differences, and so also are differences in the con- 

 figuration and superfices of visible images. It may be perceived, 

 then, that the/orm of all visual phenomena is quantitative. Hence 

 the conclusion that all the relations of phenomena, recognised by 

 the sense of sight, whether pleasing or displeasing, are funda- 

 mentally proportional relations and the science of aesthetics, a 

 science of definite proportional relation — that is to say, the beau- 

 tiful in form, in colour, and in light and shade consist in those 

 definite proportional relations which are apposite to the sense of 

 sight to the eye, and these it is the aim of a science of aesthetics to 

 formulate. The lecturer, however, has not limited his investiga- 

 tion to the sense of sight; he has analysed the jihcnomena of the other 

 senses, and has been led to make the following important generalisa- 

 tion, which he believes will aft'ect the whole ftiture current of 

 human thoughts, viz., that the form* of phenomena, of experience, 

 of knowledge is quantitative. If this be a correct generalisation, then 

 adoptation to purpose, fitness, resolves itself into adaptation of pro- 

 position to purpose ; evolution, deveiopmefit, into the becoming of 

 the proportioned in all thingst ; polities, into the proportioned 

 adjustment of material interests, and of social relations ; ethics 

 into the science of proportioned conduct; hihiiene into the science 

 of proportioned living; education into the science of training and 

 developing a proportioned or beautiful race ; asthetics into the 

 science of proportioned taste; and _/ine m-t into proportioned art. 

 Mr. Thomas has completed a work treating all the above subjects 

 fully on this mathematical basis. 



S.4FETV <>v Iron Pillars i.\ Cases of Fire. — We stated some time 

 since that, owing to the upper stoi'ies of a building in Berlin falling 

 in during a fire by the giving way of cast-iron pillars, the Prussian 

 police authorities had issued an edict forbidding the use of cast-iron 

 pillars in any inhabited building, but permitting the ttse of wrought- 

 iron pillars. Cast-iron may only be used provided that each pillar 

 is surrounded by a fixed casting of sheet iron, in such a manner 

 that there is .a good air-space between the two. This edict has 

 provoked much criticism and opposition, and several authorities 

 have reasoned against it, as well as made experiments to disprove 

 the assumption on which it is based. Professor Bauschinger, of 

 Munich, recently made a long series of actual trials with pillars of 

 both cast and wrought-iron. He loaded them with the weights 

 that they are usually allowed to bear in buildings, and heated 

 them first to 300 deg. Cent., then to 000 deg. Cent., and finally 

 to a red heat, and let a stream of cold water play on them, exactly 

 as would be the case in a fire being extinguished by iire-engincs. 

 The cast-iron pillars were much damaged and cracked by this 

 treatment, but continued to carry their loads (juite safely, while 

 those of wrought-iron were much bent before redness was reached, 

 and so twisted when cold water was squirted on to them that they 

 could not carry their loads. The conclusion is that cast-iron is 

 really far safer for buildings than wrought. Pillars of other 

 materials were also experimented with — viz., natural stone, brick, 

 and concrete. The latter stood the test best, resisting a fire of 

 three hours' duration. Also pillars of ordinarj' brick stood very 

 well, but granite, sandstone, and other natural stones did not 

 show as much resistance. If the obnoxious edict of the Berlin 

 police has done no other good, it seems at least to have set a good 

 many people to work on this important subject. — Engineering. 



* Form is here used in its philosophical sense, and as implying 

 that of whatever other attribute we can divest experience, we can- 

 not divest it of the attriliute of quantity. 



t Kvolution in man includes the proportioned development of 

 the body, of the sense, and of the intellect. The proporWoned is 

 the goal of nature. 



