Nov. 25, 1875] 



NATURE 



69 



holars, a distinguished artist, and numbers of persons of more 

 ■ n average culture ; yet there appears to be no correspondence 

 tween the mind and the length of the index finger. 



R. A. N. 



I 



Extraordinary Tides 



In last week's "Notes" you say, speaking of the unprece- 

 dentedly high tide of the 15th inst., that "no one seems to have 

 expected an unusual tide." Allow me to state, sir, that in the 



.•ctator of Nov. 7th, 1 874, I predicted this extraordinary tide. 



^ a matter of fact, the tide was higher than that of March 



74, through the unusually swollen state of the river by floods 



\ the N.W. gale. 



No extraordinary tide can occur this side of March 1878. 



4, Buccleuch Place, Dulwich B. G. Jenkins 



Further Linkage Work 



In the interesting communication to Nature, vol. xii. pp. 

 2T4-216, Prof. Sylvester gives account of the Hart and the 

 ~ !vester-Kempe "linkages." Of four points, three have work 

 jned. Prob'em : To employ the nondescript point. 



i irst. — The Hart linkage yieHs the Cissoid, exactly as that 

 curve is defined. Thus, with / circling, q resting, and s tracing 

 straight line; r traces cissoid. Second. — The Sylvester-Kempe 

 linkage yields the Hyperbola, in that cur\'e's simplest vector form. 

 Thus, with r opposite, to / resting, and pq, ps in constant direc- 

 tions ; r traces the hyperbola whose assymptotes are these 

 directions. Geo. J. P. Grieve 



Burntisland, N.B. 



A Criminal Dog 



I WAS so much pleased with the anecdote in Nature (voL 

 xfii p. 36) of the criminal dog who buried the cat he had 

 murdered, that I told my wife ; but I did not mention the breed 

 vt the dog. 



She said, " Was it not a retriever ? because they always bury 

 flieir food, so that it may become high." I could but answer 

 that it was a retriever, and added that I was afraid she had hit 

 npon the real reason for the act. R. S. Culley 



General Post Office, Nov. 12 



OUR ASTRONOMICAL COLUMN 



The Binary Star 44 Bootis.— In No. 2,064 of the 

 Astronomische Nachrichien, Dr. Doberck, of Markree 

 Observatory, has given an orbit of this binary, and a 

 comparison with measures to the present year. The 

 elements are — 



Peri- astron passage 



Node 



Peri-astron from node on orb't 



Inclination 



Excentricity 



Semi-axis major ... 



Period of revolution 



1783 01 



65° 29' 



1° 18' 



70° 



5 

 o • 71 



3" '093 

 261 • 12 years. 



Dr. Doberck makes no reference to Sir W. Herschel's 

 se'ond measure in 1802, giving for the angle 62° 59', or 

 less than 3° in advance of his measure 1781, August 17, 

 when the companion was first detected. The measure of 

 1802 was registered s.p. and "corrected by a subsequent 

 obser\'ation to n.f.," as Sir John Herschel states in 

 Memoirs R. A.S. vol. v, p. 46 ; but it is now pretty evident, 

 from a projection of all the measures to 1875, that the 

 quadrant was correctly registered s.p., and consequently 

 the angle for 1802 '246 should be 207° i' according to our 

 present method of reckoning. The angle calculated for 

 this time from the above orbit is 206° 55', and this close 

 agreement must be taken as very satisfactory evidence 

 that Dr. Doberck has given us something like the true 

 orbit, notwithstanding the difficulty of the case. It had 

 been surmised that Sir \V. Herschel's measures were 

 to be increased 180°, Struve, in 18 19, obtaining an 

 angle of 228°, and Herschel and South, in 1821, 229°, 

 but the position of the companion on the preceding 



side of the principal star, instead of the following 

 side where it had been seen in 1781, was accounted 

 for both by Sir John Herschel in his " Microme- 

 trical Measures of 364 Double Stars," and by Struve in 

 " Mensura; Micrometricae," by supposing motion in an 

 orbit passing nearly through the eye of the observer, with 

 the longer axis of the ellipse but slightly inclined to the 

 meridian. Dr. Doberck finds an inclination to the tan- 

 gent plane of the heavens, of 70°. Calculating from his 

 elements, the following appear to have been the angles 

 and distances from 1785 to 1800 : — 



i785'o ... Position 74° -o ... Distance o"-85 



90-0 ... „ 98 -3 ... „ o -55 



92-5 ... „ 132 o ... „ o -50 



1795-0 ... „ 162 7 ... „ o -53 



i8oo-o ... ,, 199 -o ... „ o -86 



The calculated distance for epoch of Sir W. Herschel's 

 measure in 1781 is o"'89, and for that of 1802, i"o5 ; the 

 observed distances being only by estimation in diameters 

 of the companion, g^iving " \ or J diameter " of smaller 

 star in 1781, and "barely \ diameter" in 1802, with 

 power 460 in both years, are perhaps sufficiently well 

 represented, though very admissible correction to one or 

 two of the elements may diminish the distance in 

 1802 or increase that in 1781. 



For comparison with future measures we have from 

 Dr. Doberck's orbit — 



i876"o ... Position 24i'''45 ... Distance 4' -887 

 78-0 ... „ 241 71 ... „ 4 928 



8o-o ... „ 241 -97 ... „ 4 -971 



The Minor Planets. — In No. 35 of the Circulars of 

 the Berliner Astronomisches Jahrbiich, Prof. Tietjen 

 notifies an arrangement which has been entered into by 

 the Observatories of Leipsic, Leyden, Lund, Pola, and 

 Vienna, for the more systematic and regular observation 

 of the small planets. These Observatories have agreed 

 to report to the editor of the Jahrbuch, every fortnight, 

 the names or numbers of the planets which have been 

 obser\'ed, with the dates of observation and the limits 

 within which the planets whose positions are more un- 

 certain have been sought. These communications will 

 be so timed that they may arrive at Berlin on the ist and 

 15th of the month, and will be there arranged, printed, 

 and circulated. An invitation is extended to those Obser- 

 vatories where the small planets are occasionally, though 

 not regularly, observed, to join in the proposed scheme. 

 In the same manner the state of calculation as regards the 

 various members of this group will be made known. The- 

 Milan Observatory has already engaged itself to calcula 

 tion for No. 151. 



Mr, Daniel Kirkwood, of Bloomington, Indiana, writes 

 with reference to the resemblance which exists between 

 the elements of certain minor planets, instancing as the 

 most striking case that of No. 54, Alexandra, and No. 

 141, Lumen. An inadvertent application of the angle 

 usually designated » (or the distance of perihelion from 

 node) in the wrong direction, renders the similarity 

 between the orbits of these planets somewhat less striking 

 than in Mr. Kirkwood's communication, but there is 

 nevertheless considerable resemblance, as the following 

 figures will indicate : — 



Alexandra. LumeK. 



Perihelion 294° 16' 341" 32' 



Node 313° 49' 318° 59' 



Inclination 11° 4/ "° 33' 



Excentricity 0-1987 0-2233 



Mean distance ... 2-7093 27095 



Period .. ... 1628-9 days, ... 1629-0 days. 



The Zodiacal Light. — Those who are interested in 

 the observation of this phenomenon wiU do well to be on 

 the alert during dark evenings in the winter months. 

 The most conspicuous exhibitions of the light in this 

 country during the last few years have occurred in the 

 month of January, the long standing recommendation to 



