Dkcembkb, 1901.] 



KNOWLEDGE. 



273 



results obtainotl by Prof. A. S. Horscliol and Dr. Von 

 XiessI, including: IGG additional fireballs, I get the 

 following : — 



Ueiffht at Xiimberof Por- 



*lisapi*earaiioo. Firelwillg. oontuRi*. 



Less than 12 niilos .. 15 . 5" 



12 to 21 miles ... 55 ... 210 



22 to 31 „ ... 79 . 30 2 



32 to 41 „ . 39 U-9 



42 to 51 „ ... 37 .. 141 



52 to Gl „ ... 24 ... 92 



Exceeding fil milos . l.'i 5'0 



Thus the independent values derived from the investi- 

 gations of Prof. Herschel and Dr. Von Niessl gejierally 

 corroborate those obtained at Bristol, though they do 

 not indicat^e such an exceptional rarity in the dis- 

 appeai'ances between 'M and 42 miles. 



Prof. Hersehel's heights at disappearance seem pretty 

 evenly distributed between 19 and 30 miles, while the 

 same may be said of Dr. Von Niessl's from 18 to 28 

 miles. 



With reference to the length of path, shooting stars 

 do not often extend over 50 miles, though in rather 

 exceptional cases, when the radiant closely borders the 

 horizon, they may considerably exceed 100 miles; as, for 

 example, the Aquarid of 1900, May 3, already referred 

 to. But the luminous flights of the slow-moving fireballs 

 are usually more than 100 miles in length, and such 

 objects often furnish grand spectAcles, remaining visible 

 from about five to twelve seconds, exhibiting a vciy inter- 

 mittent light, and flashing out brilliantly several times 

 as they plough their way through the atmosphere. 

 Dr. Von Nies-sl's mean length of patli for many large 

 meteors obsen'ed from the continent of Europe and 

 America is much gi-eater than that deduced from similar 

 objects seen in England. Possibly the discordance may 

 be in pai-t explained by the fact that in this country 

 the sphere of observation is so curtailed that the visible 

 limits of very long-pathed meteoi-s cannot be followed, 

 there being no observers in the region nearly under the 

 beginning or end points which must often be placed 

 vertically over the sea. In other parts of Europe and 

 in America, however, the vast expanse of country enables 

 large meteoi-s to be successively seen at distant stations 

 underlying their lines of flight. Thus the fireball of 

 1868, Sep. 5, was computed by Dr. Von Niessl to have 

 traversed a path of 1770 miles, from Servia to France. 



It is seldom that either fireballs or shooting stars are 

 first seen at heights exceeding 100 miles, and it appears 

 questionable whether any have ever been observed at 

 an elevation reaching 130 miles. Heis and Niessl 

 give rather numerous instances where the computed 

 heights have been over 130 miles, and I have also met 

 with a few cases of abnormal elevation, but so far as recent 

 investigations enable me to form a just opinion, I con- 

 clude that a meteor with any part of its real path at 

 a height exceeding 100 miles must be regardetl as a 

 rarity. The very swift meteors begin their observed 

 luminous careers at heights from about 90 to 75 miles, 

 while the slow meteors commence at elevations ranging 

 from 75 to 55 miles. 



An observer, after long acquaintance with the details 

 of these observations, and after much practice in the 

 computation of the heights of meteors, the fall of many 

 of which he has himself witnessed, can generally estimate 

 the height, length of path and velocity of an object to 

 within small limits of error, immediately after seeing it. 

 He can often assign the radiant correctly, and, having 

 carefully noted all the visible features of the object, he 

 recognises it as belonging to a certain class and can thus 

 form a very good idea as to its actual course in the air. 



If the meteor is an ordinary Pcr.seid, observed at a time 

 of night when tlie radiant of that shower is pretty 

 elevate<l, he will bo tolerably siu'o that the flight ranged 

 from about 81 to 5G miles in height. If the object is a 

 slow-mo^■ing fireball, leaving a train of yellow sparks, 

 and directed towai'ds the eastern sky from a westerly 

 radiant not very near the horizon, he will bo tolerably 

 certain that it. descended from a height of about 60 to 

 27 miles along a path of 100 miles or more. 



But meteors sometimes display vagaries capable of 

 putting the most experienced and best judgment in 

 fault. In fact there is probably no branch of astronomy 

 in which more blundoi-s are possible and in which more 

 are actually committed than in meteoric work. Bo the 

 observer ever so practised and his knowledge of the 

 various radiants and of the details influencing their 

 correct detonnination ever so complete, he cannot 

 attribute any meteor to its centre with absolute certainty 

 that it is correct. Even when the ca.se is one in whrclr* 

 ho feels an unusual amount of confidence, he is liable 

 to find afterwards should a duplicate observation come 

 to hand, that he has been mistaken in his judgment. 

 Possibly an old observer could con-ectly assign the 

 radiant in tbrec cases out of four, but it is always a 

 difficult performance, and requires not only that the 

 direction of flight should bo very accurately observed, 

 but that all the visible features of each meteor should be 

 attentively noted, as they often serve to indicate the 

 pretty exact place of the radiant when the path alono 

 leaves it open to doubt. 



CONSTELLATION STUDIES. 



By E. Walter Maundek, f.k.a.s. 



XI.— THE RAM AND THE BULL. 



Close beneath the lower points of the greater W, 

 noticed in our last constellation-study, that is to say, 

 close beneath Beta Persei and Beta Trianguli, is the 

 small but distinguished constellation of the Ram. He 

 can also be found readily by following the stars which 

 mark thoi belt of Andromeda. Proceeding from Nu 

 Andromedse through Mu and Beta, we find at double 

 the distance between Nu and Beta, the extremely flat 

 triangle which marks the Ram's head. As Aratus 

 tells us: — • 



" \o siilendiil j,'i iii.s lii.s goldBu fleece adorn. 

 Two dimly glitter on his crooked horn. 

 If you would (ind him in the crowded skies, 

 Beneath Androniethi's briglit belt, he lies." 



Of these three stai's, the brightest, Alpha, is the furthest 

 to the north and east ; Beta, the next in brightness is 

 next also in position ; and Gamma the most southern 

 and westerly, is the faintest. A compact little triangle 

 about half-way from Alpha Trianguli to the Pleiades 

 comprises practically all the other important stars of 

 the constellation. 



The mythology of the constellation is as little striking 

 as is its actual appearance in the sky. It is, of coui-so, 

 associated in Greek mythology with the voyage of tho 

 Argo ; it is indeed the Ram whoso golden fleece tho 

 Argonauts went forth to seek. But the stoi-y carries 

 no conviction with it, nor is there anything in tho 

 sun'ounding constellations to support the legend, 

 although so great an astronomer as Sir Isaac Newton 

 held that tho stellar symbols were intended simply as 

 a record of tho Argonaulic expedition. 



An explanation which at first sight appeal's more 

 plausible, asserts that the Ram was tho constellation 



