332 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[Nov. 



satisfied himself by careful examination of tlie recorded observations, could 

 not be accounted for by tlie perturbations of the linown planets ; and that 

 the deviations far exceeded any possible limits of error of observation. In 

 reply to the question. Whether the deviations in question might not be due 

 to the action of an unknown planet? — he stated that he considered it highly 

 probable that such was the case, — being systematic, and such as might be 

 produced by an exterior plan>t. I then inquired whether he had attempted, 

 from the indications ad'orded by these perturbations, to discover the posi- 

 tion of the unknown body, — in order that ' a hue and cry' might be raised 

 for it. From liis reply, the words of which I do not call to mind, I col- 

 lected that he had not then gone into that inquiry ; but proposed to do so, 

 having now completed certain works which had occupied loo muc h of his 

 time. And, accordingly, in a letter vvhirh I received from him after his 

 return to Kiinigsberg, dated November 11, 1842, he says, — ' In reference 

 to our conver.sation at Collingwood, I annnunce to you (melde ich Ihnen) 

 that Uranus is not forgotten.' Doubtless, therefore, among his papers will 

 be found some researches on the subject. 



The remarkable calculations of iM. Le Verrier — which have pointed out, 

 as now appears, nearly the true situation of the new planet, by resolving 

 the inverse problem of the perturbations — if uncorroborated by repetition 

 of the numerical calculations by another hand, or by independent investi- 

 gation from another quarter, would hardly justify so strong an assurance 

 as that conveyed by my expressions above alluded to. But it was known 

 to me, at that time (I will take the liberty to cite the Astronomer-Koyal 

 as my authority), that a similar investigation had been independently en- 

 tered into, and a conclusion as to the situation of the new planet very nearly 

 coincident with M. Le Verrier's arrived at (in entire ignorance of his con- 

 clusions), by a young Cambridge mathematician, Mr. Adams; — who will, 

 I hope, pardon this mention of his name (the matter being one of great his- 

 torical moment). — and who will, doubtless, in his own good time and man- 

 ner, place his calculations before the public. 



J. F. \V. Herschel. 



Sir John Herschel compares the discovery of the new planet to the dis- 

 covery of the Western World : he might have added that America did not 

 take its name from Columbus, but from a later navigator. 



Professor Challis, of the Cambridge Observatory, has published a 

 statement in the Cumbrid):e Chronicle, that, in September and October, 

 18-15, Mr. Adams deposited in the two principal observatories of England, 

 those of Greenwich and Cambridge, calculations of the heliocentric longi- 

 tude, mass, longitude of perihelion, and eccentricity of the orbit, of the 

 supposed planet. M. Le Verrier published a calculation of the heliocen- 

 tric longitude of the planet last June (eight months later). 



To the personal friends of Mr. Adams the dispute must appear a ridicu- 

 lous one : seeing that his discoveries have been a subject of common con- 

 versation among them for the last two years. And they very well know 

 that modesty, which characterises profound science, alone prevented Mr. 

 Adams from making his investigations known in a more public manner 

 than by depositing them in the observatories of Greenwich and Cambridge. 

 His original intention was, we believe, not to take any active steps for the 

 publication of his investigations till the planet had been observed by the 

 telescope. 



The question seems likely to be made the subject of as " pretty" a 

 quarrel as any in which the saians have ever been engaged. At a recent 

 ■leeting of the Paris Academy, the announcement that the Engliish astro- 

 nomers meant to claim for their countryman the honour of first predicting 

 the place, &c., of the new planet was received with manifestations of the 

 utmost indignation. It is stated that in the excess of their wrath, they did 

 not refrain from designating Airey and Herschell — impostors I In a letter 

 in the National, which a correspondent of the LiteruTij Gazette attributes 

 to Arago, Sir J. Herschell and Professors Airey and Challis are said to 

 have entered into a conspiracy to rob M. Le Verrier of his discovery. 

 Herschell in particular is reviled with ingratitude because he is the son of 

 one u'hose fame M. Ara^o made knoicn to Europe.^^ This exceeds the 

 usual limits of even French bombast. 



Our own journals take up the question very coldly. Surely this cannot 

 arise from ignorance of the importance of the subject. However, "the 

 truth is great, and will prevail," and as we happen to know personally 

 that Mr. Adams's claims are indisputable, we do not for an instant doubt 

 that they will soon be established to the perfect satisfaction of the public. 



The planet is said to have a ring and a satellite : its distance from the 

 sun is three thousand two hundred millions of miles — upwards of thirty 

 times that of the earth. The distance of Uranus from the newly dis- 

 covered source of its perturbations is one hundred and fifty millions of 

 miles. The new planet is the largest in our system, except Jupiter and 

 Saturn : its cubic bulk being 250 times that of the earth. 



The Alhinicum, speaking of M. Le Verrier, says incidentally, that " he 

 worked out the problem first" ! A more heedless admission was never 

 made in a scientific journal : if it be, as it appears to be, a mere obiter 

 dictum, the result of sheer carelessuess, it ought, fur truth's sake, to be 



withdrawn immediately. M'e repeat emphatically, that it i!? notorious to 

 ourselves and to all Mr. Adams's scientific friends, that his discoverifi 

 were made long before M, Le Verrier's name was heard of in connectiijii 

 with the subject. 



INSTRUMENT FOR TRACING EAILWAY CURVES. 



Sir — The accompanying sketch and description of an instrument which 

 I have found extremely useful for setting out railway curves is well adapted 

 for all situations, and is very portable and simple. 



A r. C O'P- I) is a permanent frame or square B C being perpendicular 

 to A B, and li C is a moveable limb with a vernier to read ofif the degrees 

 on the quadrant. Instead of making the offsets as heretofore perpendicular 

 to the tangents, they are made by this instrument in the direction of the 

 secants aa 4 c, df, and A c;, &c. (fig. 2.) 



Fig. 1. Fig. S. 



In order to use this instrument, it is necessary to calculate by trigono- 

 metry the angle a b c fig. 2, and the length of the secant, for the purpose 

 of finding the length of the effect a b, the latter is equal to the dillerence of 

 the radius of the cune and the secant; in all cases it is requisite first to 

 determine what length of tangent is most suitable to the ground, on which 

 the curve is to be set out. 



After this the moveable limb B C, is fixed on the quadrant at the angit so 

 found for a b c, and the tangent a b being traced and measured on the 

 ground, the instrument is placed with B of fig. 1, corresponding to 4 of fig. 

 2, and B .A. in the direction of 4 a, being so placed the moveable limb BC, 

 fig. 1, will he in the direction of the required oflFset b c, fig. 2, which is to be 

 measured off accordingly, giving the point c (fig. 2) as the first point in the 

 curve A B. 



For the second and other points df, and A g, and a, the instrument is re- 

 versed, laying the fixed limb B C", fig. 1, on the offset 4 c. B of the instru- 

 ment corresponding with c, fig. 2, the line A B of the instrument being per- 

 pendicular to 4 c, will consequently point on the ground in the direction of 

 the second tangent c d, and at d the second operation is to be performed as 

 at 4, for the oti'set df, and so on. 



The circular openings at \ B C, and c, are for the purpose of receiving 

 nicely fitted rods to keep the instrument in its proper positions on the ground 

 until the necessary prolongations a 4, and b c, and a have been made. 



Wii. Ta:t. 



Military Library, 30, Charing Cross. 



