136 



KNOWLEDGE 



[June 1, 1894. 



Periodic 

 Time. 

 Years. 

 7073 

 8-534 

 6 378 

 6-909 

 6-309 

 6-745 



1 95023 

 l-353(i7 

 1-81791 

 2-13940 

 1-42911 

 1-21 



Perihelion Time Perihelion 



Passage. -s-o^^c' Distance. 



1SS9, Sep. 30 



1889. Nov. 29 



1890, Oft. 26 

 1892, June 13 

 1892, Dec. 11 

 1894, Feb. 9 



It will be noted that the perihelion distance of each of 

 these bodies lies considerabl\' outside the earth's orbit. It 

 follows, therefore, that on reaching perihelion at a time 

 when the earth is on the same side of the sun, they are 

 very favourably visible during a considerable part, if not 

 the whole, of the night. An encouraging line of observa- 

 tion is thus indicated to those interested in this branch, 

 for careful sweeping amongst the zodiacal constellations 

 may certainly be expected to reveal further periodical 

 comets belonging to Jupiter's already numerous family. 



Bristol, May 22nd, 1894. W. F. Denning. 



To the Editor of Knowledge. 



Deae Sm, — Prof. Barnard, in his article on "Magnifying 

 Powers," refers to the fact that Saturn will bear the 

 application of higher powers than Jupiter as a " singular 

 peculiarity." I gave what appears to me to be the correct 

 explanation of this matter in the Journal of the LirerpooJ 

 Astronomical Society for February, 1886. 



The focal image of any object of sensible diameter very 

 much resembles the beautiful photographic reproductions 

 which you give us in Knowledge. It is a stippled image, 

 being made up of minute discs ; but it differs from the 

 photographs, in that in the focal image the bright pomts 

 are so close in proportion to their diameter as to 

 overlap. It is exactly as if the image were made up of 

 closely set stars, which with sufficient power exhibit a 

 spurious disc and rings. Any power that raises a disc 

 upon a star -will also raise a disc upon every point of a 

 bright object, and this will soften the outlines and detail ; 

 but as a star disc is not a uniformly luminous patch, but is 

 brightest in the centre, fading gradually to the first dark 

 interference ring, it follows that with loss of brilliancy 

 less of the spurious disc is intense enough to impress the 

 retina, and a less brilliant star apparently gives a smaller 

 disc. As the planets are less bright than stars, the 

 spurious discs of which their outlines and details consist 

 are smaller, and the less brilliant of two planets will be 

 built up of the smaller discs, or finer stippling, and will 

 stand a higher power before the softening effect which results 

 is manifest. Saturn is less bright than Jupiter, therefore 

 it should theoretically bear a higher power, as it is found 

 to do in practice. Jupiter sends us much more light than 

 a star, but that is because of his larger apparent diameter. 

 His surface brightness is, however, much less than would 

 be derived from an equal area of bright stars, but area for 

 area he is much brighter than Saturn. This, I think, 

 explains why Saturn bears more magnifying than Jupiter. 



Yours faithfully, 



Edwin Holmes. 



[If Mr. Holmes is correct, the definition of the details 



visible upon Jupiter's surface should be imi^roved by the 



judicious use of a dark wedge. — A. C. E.\ny.\bd.] 



— ■ » I — 



A BLACK AURORA. 



To the Editor of Knowledge. 



Sir, — In connection with your remarks on this 

 phenomenon in the April issue of Knowledge, I ought 

 perhaps to mention that the haze or cloud- haze in question 

 seemed pretty high up, and appeared to form rapidly in 

 the clear sky before the aurora was seen, as, indeed, often 

 happens. You are probably right in supposing the black 



rays to be intervals between luminous streamers. I could 

 see no luminous beams, but they might have been feeble 

 or even above the layer of illuminated haze, which was 

 apparently thin. Yours, J. Mdnro. 



— *-♦.< — 



To the Editor of Knowledge. 



Blackheath. 

 De.\b Sir, — It may interest your readers to know that 

 a very large and brilliant meteor was observed here on 

 Sunday evening, the 22nd April, at 7.35 p.m., travelling 

 almost due south. The nucleus was extremely bright, and 

 appeared to scintillate, throwing off small jets of flame, 

 which would, I presume, indicate that it was in a state of 

 semi-explosive combustion. No stars being visible at the 

 time — it being still daylight — I cannot say exactly through 

 what constellations it passed, but probably a line drawn 

 from the Great Bear to Leo Major would indicate its 

 path. It burst silently at about the latter point. 

 Yours faithfully, 



F. Montague -James. 



THE QUEEN BEE. 

 To the Editor of Knowledge. 



Sir, — In reading the interesting paper on " Stinging 

 Insects" in last month's Knowledge, I was much surprised 

 to find the queen of the hive bees [Apis nullinca) referred 

 to as being " the mother as well as the ruler of the hive." 

 The latter part of this statement is, I think, quite 

 erroneous ; the mother bee can in no sense be called a 

 ruler. She is, during the breeding season, an object of 

 great regard and attention on the part of the workers, and 

 this, together with her long, graceful form — quite unlike 

 that of the little worker or the burly drone — may perhaps 

 have given rise to this poetic fiction. She moves over the 

 combs attended by a retinue of worldng bees, who offer 

 her food from time to time as she is engaged in depositing 

 her eggs in the cells prepared for their reception. The 

 sole function of the queen is to lay eggs, which, as soon as 

 deposited, are taken charge of by the workers, and are 

 attended to by them through the various stages of develop- 

 ment. If the queen, through an accident or old age, 

 ceases to be prolific, she is cast out without mercy, and 

 the workers raise another queen. 



The whole of the affairs of the hive are regulated by the 

 worker bees— some being attendant on the queen, some 

 acting as nurse bees to the young brood, some gathering 

 pollen, some buildmg new comb, others gathering 

 propolis for sealing all the chinks and crannies of the 

 hive, some guarding the entrance to the hive against 

 the predatory attacks of stocks ui less flourishing cir- 

 cumstances, whilst others (and by far the greatest 

 number) are gathering honey for the benefit of the whole 

 community. 



But though all this is done without confusion, and in 

 the utmost order and harmony, there is, as far as I am 

 aware, no evidence of one having more authority than 

 another. A beehive is almost an ideal commune, where 

 the daily and nightly labours are distributed and transacted 

 with the most beautiful regularity and precision, each 

 doing its own portion with a restless, untiring zeal which 

 is marvellous. 



But by what mysterious means of mter-communication, 

 or by what strange instinct all this wonderful work is 

 arranged and carried out — much of it in the darkness of 

 the hive — so rapidly, with unerring precision, and with 

 the most perfect harmony, who can tell ? 



Yours truly, 



Lancaster, April 16tb, 1894. J. T. Denham. 



