March 1, 1899.] 



KNOWLEDGE. 



63 



" Elements of Astronomy," viz., 100^ 21' 21-o" in 1850, 

 according to Leverrier, and the longitude required in order 

 that it may take place on 31st December last at 10 p.m., 

 according to the Nautical Almanac. If the longitude in 

 1850 was 100' 21' 21-5", and the annual increase is 6r72" 

 (50-238" + 11-482 '), the longitude in 1898 should have 

 been 101° 10 ii", i.e., IV 10' 44 " beyond the winter 

 solstice, which angular distance it would take the earth, 

 travelling at its maj-imum orbital velocity (01' 9' per diem), 

 ten days twenty-three hours fifteen minutes to traverse, 

 thus bringing us to 6h. 15m. p.m. on 1st .January (taking 

 winter solstice at 7 p.m. on 21st December), instead of the 

 time given in the Almanac. The sun's apparent longitude 

 at noon on 3l3t December, according to the Almanac, was 

 279° 53' 31-9' , which would make the earths 99° 53' 31-9", 

 addmg 23' 28-75 ' for the ten hours makes 100° 17' 0", 

 which is 4' 21-5" less than Leverrier's figures for 1850. If 

 those figures are wrong, why are they given in the last 

 edition of Sir K. Ball's book above mentioned ? 



Perplexed. 



[The discordance is due to the perturbation of short 

 period which the moon and planets produce on the earth's 

 motion. Perturbations are divided into two classes, secular 

 and periodic. The advance of the perihelion through 

 11-48" per annum (or through 61-72" referred to the 

 vernal equinox) is a secular perturbation. These secular 

 perturbations have the effect of causing the earth's elliptical 

 orbit to slowly vary, the variations being for long periods 

 uniform both in direction and in amount. The periodic 

 perturbations cause the earth to oscillate from one side to 

 the other of this slowly varying ellipse. One of these per- 

 turbations is very easy to understand ; it is due to the 

 earth describing a small ellipse once a month about the 

 centre of gravity of the earth and moon ; owing to this 

 motion the earth's centre is alternately inside and outside 

 the mean orbit by an amount of some three thousand 

 miles. The planets produce the waves in the earth's 

 motion of large periods and of comphcated forms. Hence 

 it is clear that the position of the earth when nearest the 

 sun is not the same as the perihelion point of the slowly- 

 varying eUipse which is given in the table quoted by 

 " Perplexed." If, however, he takes the values for several 

 years from the Nautical Almanac he will find that they fall 

 sometimes on one side, sometimes on the other, of the 

 values given by the formula he uses. For example, take 

 the following cases : — 



Longitude of Value by 



Time of Perihelion. Earth. FormiJa. 



D. H. o ' o ' 



1896. .January 1 7 100 56 101 9 



1896. December 30 22 100 18 101 10 



1898. January 2 1 102 13 101 11 



1898. December 31 10 100 19 101 12 



1900. January 1 18 101 26 101 13 



In three cases the actual longitude is below the tabular, 

 and, in two cases, above it.] 



Brttig^ ©rntti^ologtral Notes. 



Condiicted by Habby F. Witherby, f.z.s., m.b.o.u. 



• 



On the CoMPARATrvE Ages to which Birds live. By 

 J. H. Gdrney, f.z.s. {Ibis, January, 1899, pp. 19-42). — 

 In a very interesting article under the above title, Mr. 

 Gurney, after deploring our want of knowledge on the 

 subject, discusses a number of facts, collected from various 

 books and papers, regarding the age to which birds live. 

 Stories of birds having lived to enormous ages are, of 



course, plentiful. Of more or less authentic records, the 

 greatest age, that of eighty-one years, seems to have been 

 attained by a sulphur-crested Cockatoo. A domestic 

 Goose was recorded by Willughby as having been killed on 

 account of its destructiveness at the age of eighty. A 

 Mute Swan, called " Old Jack," died at the age of seventy 

 in St. James' Park in 1840. Mr. Dresser, in his " Birds 

 of Europe," gives an instance of a Raven having lived 

 sixty-nine years. Mr. Meade- Waldo has in captivity a 

 pair of Eagle Owls {Bubo ma.vimiis), one of which is sixty- 

 eight and the other fifty-three years old. Since 1864 

 these birds have bred regularly, and have now reared 

 ninety-three young ones. A Bateleur Eagle and a Condor 

 in the Zoological Gardens at Amsterdam are still alive at 

 the respective ages of fifty-five and fifty-two. An Imperial 

 Eagle of the age of fifty-six, a Golden Eagle of forty-six, 

 and a Sea Eagle of forty-two, and many other birds of the 

 age of forty downwards are also recorded. Mr. Gurney 

 discusses the probability that some families or even aUied 

 genera of birds may attain a greater age than others, but 

 owing to the want of information no satisfactory conclusion 

 can be arrived at. The author suggests that wild birds 

 might be marked with an aluminium or white metal ring, 

 bearing date and name of place. 



T/ie Rufous Warbler, a bird new to Ireland {Irish Saturalist, 

 February, 1899, p. 52). — Mr. R. J. Ussher announces that a supposed 

 Nightingale, preserved for tn-enty years in the museum of Queen's 

 College, Cork, and now faded, has been identified by Mr. Howard 

 Saunders as a Rufous Warbler (Aedon galactodes), a southern species 

 which has been obtained in England only three times, and has never 

 before been recorded for Ireland. The bird was shot by Mr. F. K 

 Bohu, at the Old Head of Kinsale, in September, 1876. 



JTondchaf Shrike, a bird nein to Ireland (Ibis, January, 1899, p. 

 loS). — Mr. Richard M. Barrington writes to the Ibis that in 1893 he 

 received from Mr. Patrick CuUen, master of the IJlackwater Hank 

 Lightship, County Wexford, the leg and wing of a bird killed by 

 striking the lantern on August 16th. Mr. Barrington has lately sent 

 the wing and leg to Mr. Howard Saunders, who recognized them at 

 on:;e as belonging to tlie Woodchat Shrike (laniiis pomeranus), a 

 butl which has never before been known to occur in Ireland. 



Sesting of the Goshawk in Yorkshire (Zoologist, January, 1899, 

 p. 28). — An adult female Goshawk (Astiir palumbarius), together 

 with two of its eggs, have recently been presented to the Norwich 

 Castle Museum. Mr. Thomas Southwell states that the bird was 

 shot at its nest about May 13th, 1893, by Mr. W. M, Frank, a keeper 

 on an estate at Westerdale, Cxrosmont, Yorkshire. "The only question 

 is : Was this a truly wild bird, or an escaped one ? In commenting 

 upon this question, Mr. Southwell says that the keeper is unable to 

 state with certainty as to whether the bird had a mate or not; that 

 the bird was very wild ; and that " the inner toe of the right foot is 

 missing, evidently au old injury, as the stump is quite healed." 

 Should anyone have lost a Goshawk in the early part of 1893, the loss 

 of the toe may lead t« its identification. Mr. Southwell remarks : 

 " Since the instance reported by Colonel Thornton, who received a 

 nestling from the forest of Rothiemurchus, ' prior to 1804,' I believe 

 there is no authentic instance of its having bred in Great Britain, 

 although it has been suspected of having done so." 



Richard's Pipit in Cumberland (Ibis, January, 1899, p. 155). 



The Rev. H. A. Macpherson has identified a specimen of Anthus 

 richardii, whicli was shot by Mr. Tom Williamson, on October 10th, 

 1898, on Edderside Moss, near Allonby, Cumberland. 



Barred Warbler in Oj/'orrfiA!>e(J4i.9, .January, 1899, p. 160).— Mr. 

 O. V. Aplin obtained a specimen of Sylvia nisor'ia on November 28th, 

 1898, at Bloxham, Oxon. Mr. Aplin remarks that this specimen (the 

 sixteenth procured in these Islands) " had wandered further inland 

 than any of the other Barred Warblers which have straggled to our 

 shores." 



The Introduction of the Slack Grouse and of some other Birds 

 in Ireland. By G. E. H. Barrett-Hamilton, B.A., p.z.s. (Irish 

 Naturalist, February, 1899, pp. 37-43).— Tliis is a careful paper, 

 dealing chiefly with the many unsuccessful attempts which have been 

 made from time to time to introduce the Black Grouse into Ireland. 



All contributions to the cohimn, either in the way of notes 

 or photographs, should be foncarded to Harry F. Witherby, 

 at 1, Eliot Place, Blackheath, Kent. 



