344 



SCIENCE. 



[Vol. XXII. No. 568 



errors, and that the whole subject of time had fallen into 

 confusion," is the result of an incorrect standard of time 

 having been used, and still being used. 



Seventh: By the present accepted theories!, it is not 

 known whether the annual rate of decrease in the obliq- 

 uity (which is the same thing as a decrease in the distance 

 of the Pole of the Heavens from the Pole of the Ecliptic) 

 has a decreasing or increasing rate. It is now, and has 

 been during many years taken as a constant quantity of 

 0.476" annually, which is geometrically as unsound, as 

 though it were stated that the Polar distance of a star 

 decreased each year at a uniform rate. It is not known 

 how long this decrease in the obliquity will continue, or 

 when it will become an increase. It has continued during 

 1800 years at least, but when it commenced is not known. 

 What the obliquitj- was 5,000 years ago, and what it will 

 be 5,000 years hence, is not known ; because the true 

 course traced by the Pole of the Heavens relative to the 

 Pole of the Ecliptic has not been known. 



The Second Rotation supplies all these details, and 

 proves their accuracy, by the agreement of calculation 

 with recorded observations. The detail movements of 

 every zenith are given by the Second Rotation, whereas 

 hitherto all zeniths seem to have been imagined to be 

 similarly affected by the so-called "Conical Motion of the 

 Earth's axis.'' It is impossible to conceive more convinc- 

 ing proof of the truth of Drayson's discovery. The Sec- 

 ond Rotation of the Earth merely gives accuracy of de- 

 tail where hitherto there has been vagueness and imper- 

 fect definition. 



The various statements that have been confidently j)ut 

 forward regarding the impossibility of any great change 

 having occurred in the Arctic Circles and Tropics, is due 

 to the fact that the true course of the Pole of the Heav- 

 ens relative to the Pole of the Ecliptic has hitherto been 

 unknown. Such statements, however, having been ac- 

 cepted as if they were statements of fact, without full 

 enquiry, have induced some writers to put forward extra- 

 ordinary theories incapable of being proved, to account 

 for an Arctic climate having descended to about 54"^ lati- 

 titude within comparatively modern times. 



Considering that the true course of the Pole had never 

 been accurately defined until the Second Rotation was 

 made known, it apj)ears sti-ange that so many forms of 

 vague speculation should be seriously discussed as a pos- 

 sible cause of the glacial epoch, whilst the fact that the 

 centre of the circle which the Pole describes is proved to 

 be 6° from the Pole' of the Ecliptic, has been overlooked, 

 or considered quite imjDOssible. 



More especially is this neglect remarkable because 

 twenty-five years ago the dates for the duration and ter- 

 mination of the Glacial Period were accurately given by 

 Drayson in consequence of a knowledge of this beautiful 

 movement, and when scarcely a geologist believed that 

 the dates were anything but erroneous; and now what 

 do we see "? Geologists substantiating by evidences 

 which none can doubt, the absolute accuracy of his ob- 

 servations and calculations. 



It is to be expected, after such results, that astron- 

 omers will define, in unmistakable terms, the true course 

 of the Pole of the Heavens relative to the Pole of the 

 Ecliptic. The definitions of the past will not and cannot 

 satisfy, and a consideration of the following questions 

 ought not to be beneath the notice of any one, because 

 until the matter is solved conclusions as to the proper 

 motion of stars, the changes of latitude of observatories, 

 and even the variation in eccentricity of the Earth's orbit, 

 are assumjDtions only, based upon unsound foundations. 



1. Is the true course of the Pole a circle round the Pole 

 of the Ecliptic as a centre, keeping constantly at 23*^ 28' 

 from it as stated by Herschel and other writers ? 



2. Is it an irregular curve always moving at right 

 angles to the arc joining the Pole of the Heavens to a 

 movable Pole of the Eclif)tic? 



.3. Or, is it a circle round an undefined point, which is 

 supposed to be the mean position of a movable Pole of 

 the Ecliptic ? If so, where is the point ? 



It is probable that the facts of the Second Rotation 

 have not been carefully examined, as it appears that some 

 individuals hold the opinion that it is merely a vague the- 

 ory opposed to well established facts in astronomy. The 

 very reverse is, however, really the case, and the follow- 

 ing are some amongst many problems which can be 

 solved by a knowledge of the Second Rotation of the 

 Earth. 



Such problems cannot be solved by those persons who 

 are unacquainted with it. 



Problem 1. — Calculate the mean obliquity of the Ecliptic 

 for any date, say the 1st of January, 1873, without ref- 

 erence to the oloserved obliquity at any previous date, 

 and without reference to the annual rate of decrease 

 found by observation. 



Where EC=6°-CP=29° 25' 47", and the angle ECP 

 for date 1st January, 1873, is found thus: 



(2295. 2-1873) x40.9"=4° 47' 47.9" = angle ECP on 

 the 1st January, 1873. 



On calculating the value of the side PE, which is the 

 obliquity, this value is found to be 23'' 27' 20.2", and it is 

 recorded in the Nautical Almanac, 1873=23'' 27' 20.88". 



Problem 2. — In Bradley's catalogue of stars for 1st 

 January, 1755, the mean north Polar distance of AljAa 

 Draconis w'as given as 24'^ 26' 47.4". This star is 

 26° 37' 3" from C, the pole of Second Rotation.- Cal- 

 culate" the mean North Polar distance of this star for any 

 other date, say 1st January, 1850, and 1st January, 1890, 

 without any reference to the annual rate of variation in 

 North Polar distance of this star. 



Solution. — the star. Q 



B^/\f^LEr) 



From a knowledge of the Second Rotation: 

 The side PC=29^" 25' 47". 

 The side Ca=26'' 37' 3". 



From Bradley's Record Pa=24° 26' 47.4" on the 1st 

 January, 1755. 



