John Frederick William Herschel

English astronomer, 1792-1871

"Sir John Frederick William Herschel, 1st Baronet was an English polymath, mathematician, astronomer, chemist, inventor, and experimental photographer who invented the blueprint. Herschel originated the use of the Julian day system in astronomy. He named seven moons of Saturn and four moons of Uranus – the planet discovered by his father Sir William Herschel. His ""Preliminary Discourse"" (1831), which advocated an inductive approach to scientific experiment and theory-building, was an important contribution to the philosophy of science. He published a catalogue of his astronomical observations in 1864, the ""General Catalogue of Nebulae and Clusters""."

Source: Wikipedia

Herschel, John Frederick William

Astronom (1792–1871). Eigenh. Brief mit U. („JFWHerschel“). O. O. 1 S. auf Doppelblatt. 8vo. Mit eh. Adresse (Faltbrief).
$ 697 / 600 € (18119)

John Frederick William Herschel (1792–1871), Astronom. E. Brief mit U. („JFWHerschel“). O. O. u. D. [vor 1857] S. auf Doppelblatt. 8°. Mit e. Adresse (Faltbrief). – An J. Hudson von der Royal Society: „I left my papers at the RS Apartmt. the other evening – may I beg the favour of you to let the Porter bring them here as soon as convenient [...]“. – Der Sohn des Astronomen Wilhelm Herschel übernahm von diesem dessen Sternwarte, „entdeckte, daß die Magellanschen Wolken aus Sternen bestehen, gab verschiedene Sternen-Kataloge heraus und führte das Julianische Datum in die Astronomie ein [...] Seine Vielseitigkeit beweist auch die Anwendung der Lichtempfindlichkeit bestimmter Eisensalze zu damals neuen photographischen Verfahren.

Er verbesserte die Cyanotypie. 1842 entdeckte er den photographischen Prozeß zum Belichten von Papierbildern auf der Basis von kolloidalem Gold, den er Chrysotypie nannte“ (Wikipedia, Abfrage v. 17. IX. 2009). – Nach Herschel wurden eine Insel in der kanadischen Beaufortsee und ein Mondkrater benannt. – Mit Siegel und leicht angestaubt..

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Herschel, John Frederick William

Astronom (1792–1871). Autograph letter signed („JFWHerschel“). Collingwood bei Hawkhurst. 4 SS. auf Doppelblatt. 4to.
$ 1,395 / 1.200 € (18976)

To an unnamed member of parliament asking for information about the forthcoming amendment of the law and the consequences for bank deposits and the „Friends Society“: „I have just seen in the Times of yesterday the Draft of a bill for the future regulations of Savings Banks. One claim limits deposits in them to 20£ in any one year. Another disallows trust accounts and a third limits the interest (after a year or so) to £ 2:13:6 per annum. If the bill is intended to affect only Savings Banks it will be to the ‚Friends Society’ merely an inconvenience – but if it be intended as the precursor of a general reduction of interest in the case of such Societies as that [...] it will I fear so far cripple us that in a district like this which is felt to be an unpromising one it will leave us very little chance of success [...] the reduction from 3½ to 2½ per Cent is a very formidable one.

– At all events it nullifies all our tables and torecalculate them at 2½ will be a work of time, serious responsibility and heavy expense – yet with the immediate prospect of this ‚Casus Foederis’ hanging over us it would I think be very unwise [...] to enter into contracts with any who may now apply which we should speedily have to modify to their disadvantage [...]“. – Slightly browned due to paper..

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Herschel, John Frederick William

Astronom und Naturforscher (1792-1871). Eigenhändiger Brief mit Unterschrift. London. 8vo. 3 pp. Doppelblatt.
$ 2,906 / 2.500 € (83846)

Langer und inhaltsreicher Brief an den Berliner Physiker und Geologen Georg Adolf Erman (1806-77): „Excuse me if I reply to your valued letter in my own language having too little the habit of writing German, though I read it with facility. The best thing wich I can do in the matter of Herrn Siemerings Bust of the lamento & his missal Bessel will I think be to lay your notice of it before the R. Astronomical Society, together with the Photograph which accompanies it. All present however is in the needs of the Society which will not resume it sittings for some months.

In meanwhile I beg you will make to Mr Siering my very grateful […] for the photograph in question while is a fine thoughful heart - though with something of an air of sadness which does not quite allow with my […] of him […].

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Herschel, John Frederick William

Astronom und Naturforscher (1792-1871). Autograph letter signed. London. 1 S. Qu.-8vo. Mit eh. Adresse (Faltbrief).
$ 1,395 / 1.200 € (941314/BN941314)

To the Austrian physicist and mathematician Andreas von Ettingshausen (1796-1878): "The enclosed was addressed by me to the Lord von Hammer-Purgstall President of the Imperial Academy in Vienna. - It has now been returned to my hands from Vienna by the Post office, as having been refused being written on 'nicht angenommen'. - Permit me therefore to request you as Secretary to the Academy to receive it as conveying my thanks to that body and to request your attention to the Post-scriptum and believe me to be [...]". - Paper slightly torn from breaking the seal.

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Herschel, John Frederick William

Autograph letter signed ("JFW Herschel").
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An extraordinary letter to Mr. Mr. Henn, discussing Henn's paper on object glasses and the planetary ephemerides: "It is so long since I wrote to you, you will think I have forgotten you. It is not so, but I have been so overwhelmed with business that I have been obliged to neglect my correspondence -much to my regret. Let me first acknowledge your communication on object glasses and on the planetary ephemerides, if I have not already done so, with the tables and the letters accompanying them. They are printed (not the letters) in the forthcoming volume of the Astron. society's transactions. I have now the proof sheets of the former before me, on which allow me some remarks. 1. The second value off as it stands in your MS. is incorrect the factor 1/r + 1/s being accidentally omitted. I have rectified this in the printed copy. 2. You say [... a quote in German, followed by an equation ...]. Now this is not true of the Spherical aberration itself but (if instead of l/n2 p we write x2 /2n2 p the x2 /2 having been inadvertently or perhaps for brevity omitted by you) it is true [symbol] the function which in my paper on object glasses referred to by you, is called ?ƒ is equal to your [symbol] multiplied by [an equation]. In order to rectify this with as little alteration of your words as possible I have substituted for [a German phrase], in the English translation (by Dr. Tiarks) the words 'the coefficient of spherical aberration' and explained in a note that this 'coefficient' means the function above mentioned. 3. When you say '[a German phrase] &c' you seem to say it [doubles] as a theorem that The Spherical aberration of a double lens is Equal to the Sum of the Spherical aberration of its component lenses. Not only no such theorem can be taken for granted, but it is not correct in fact It is true that the 'coefficient' of Spherical aberration in a double lens is the Sum of the 'coefficient of S.A.' ff its component ones, but this is by no means self evident, but requires all the proof (a pretty complicated one) which is given in my paper-to which I have therefore annexed a reference. 4. In deriving my Equations (A) and (z) you have made W = dn/dn1, p=1-W, p1 = 1 W/W, and throughout your paper you have regarded the ratio of the dispersion powers (which I have called W in my Equations) as the same with that of dn: dnl whereas it is in reality dn/n -1: nd1 /n1-1 and the value of W which satisfies my equations (A) (z) is not W = dn/dn1, but W = dn/dn1 X n1 - 1/n - 1. I have therefore made this correction, and in the remainder of your paper have represented the fraction dn/dn1 not by W but by another letter [symbol] to avoid confusion. 5. You have remarked 'that the terms + [equation] and- [equation]' [it should be[ equation]] '[followed by a quote in German].' If this remark be well founded, all my theory of aberrations falls to the ground I am convinced, if you will consider the matter again, you will coincide with me that this paragraph ought not to stand, and admit that I have done right in striking it out of the printed copy. At all events, as you deduce no conclusion from it in what follows, its omission no way vitiates any part of what you have said. 6. In the first example of your very real and useful practical formulae, you have given, you have taken n = 1.53, n1 = 1.60 and you say 'zersXeiing dn = 0.0, dn1= 0.04 also W = 0.25'. Since the values of dn and dn1 are 0.01 and 0.04 the true ratio of dispersive powers or of focal lengths of the glasses is not 0.25 but 0.25 X 60/53. I have therefore struck out 'W =' and left dn/dn1 = 0.25, after which, the numerical calculations, in which W is not involved, are (I suppose) correct I cannot but remark however that no crown x flint glass hitherto met with will give dn/dn1 = 0.01/0.04. The lowest value of [equation] I know of is 0.425 for glasses. So that this example though good is a numerical illustration has no practical meaning. I cannot imagine by what mode of experimenting you have got such very small values as 0.004 and 0.008 in the specimens of glass you tried, for dn and dn1. I presume they do not relate to extreme rays, but I wish you had mentioned what rays they were determined for, and by what [means]. I hope you will now not think me a very severe critic when I tell you that I think very highly of your paper, as a most useful practical work, and which promises to be of the greatest service. A gentleman named Rogers of Lieth has made a considerable improvement (as promises) in the construction of Large telescopes -he corrects a large disc of Crown by a compound lens of crown x flint of much smaller aperture [followed by a sketch] thus. Vide the Vol. III of the Trans. Ast. Soc. I am sorry you should have thought it necessary to send the money for Dr. Pearson's book as I never intended you to pay for it at all events the (2£ 13 shill) you mention to have sent by Perther...has never come to hand. I am delighted to see that you are not contented to observe but deduce results. Your catalogues of stars whose proper motions come out from your obsns so well, are excellent examples. I wish all astronomers would go & do likewise work muchdispute little-use their eyes & draw conclusions the best they can, and trust the next sensation with their fame. I shall shortly find a way to send you my 3d Catalogue of new double stars- this completes my first thousand. What a wonderful work Struve's Catalogue is! My nebulae get on slowly but steadily. Within the last few days I have been examining the Satellites of Uranus. About two there remains no doubt-and I am almost sure there are more, but the planet is most unfavorably situated [...]". - Seal tear repaired.