Beyond the introduction of the spider line it is unnecessary to mention the various steps by which the Gascoigne micrometer assumed the modern forms now in use, or to describe in detail the suggestions of Hooke, 4 Wren, Smeaton, Cassini, Bradley, Maskelyne, Herschel, Arago, Pearson, Bessel, Struve, Dawes, &c., or the successive productions of the great artists Ramsden, Troughton, Fraunhofer, Ertel, Simms, Cooke, Grubb, Clarke and Repsold.
Sir William Herschel was the first astronomer who measured position angles; the instrument he employed is described in Phil.
Herschel writes:- " I have in vain attempted to find lines sufficiently thin to extend them across the centres of the stars, so that their thickness might be neglected."
5 Herschel and South (Phil.
Herschel being senior), was elected fellow of his college in 1814, became assistant tutor in 1815 and full tutor in 1823.
While still an undergraduate he formed a league with John Herschel and Charles Babbage, to conduct the famous struggle of "d-ism versus dot-age," which ended in the introduction into Cambridge of the continental notation in the infinitesimal calculus to the exclusion of the fluxional notation of Sir Isaac Newton.
The treatises on physical geography by Mrs Mary Somerville and Sir John Herschel (the lattewritten for the eighth edition of the Encyclopaedia Britannica) showed the effect produced in Great Britain by the stimulus of Humboldt's work.
Herschel marshals the evidence which can be collected on this point.
He arranges a selection from his observations on the nebulae in such a way as to give great plausibility to his view of the gradual transmutation of nebulae into stars Herschel begins by showing us that there are regions in the heavens where a faint diffused nebulosity is all that can be detected by the telescope.
It seemed to Herschel that he was thus able to view the actual changes by which masses of phosphorescent or glowing vapour became actually condensed down into stars.
- Laplace, Systeme du monde; Sir William Herschel, Phil.
(1814), pp. 248-284; Kant's Cosmogony, translated by Professor Hastie; Sir John Herschel, Outlines of Astronomy; Professor S.
CAROLINE LUCRETIA HERSCHEL (1750-1848), English astronomer, sister of Sir William Herschel, the eighth child and fourth daughter of her parents, was born at Hanover on the 16th of March 1750.
See The Memoir and Correspondence of Caroline Herschel, by Mrs John Herschel (1876).
Herschel, had the chief part in shaping its constitution.
It was in 1837, on reading Whewell's Inductive Sciences and re-reading Herschel, that Mill at last saw his way clear both to formulating the methods of scientific investigation and joining on the new logic as a supplement to the old.
A Orionis, very close to Orionis, is a very fine multiple star, described by Sir William Herschel as two sets of treble stars; more stars have been revealed by larger telescopes.
It may be added that he first examined the conditions of stability of the system formed by Saturn's rings, pointed out the necessity for their rotation, and fixed for it a period (Io h 33 m) virtually identical with that established by the observations of Herschel; that he detected the existence in the solar system of an invariable plane such that the sum of the products of the planetary masses by the projections upon it of the areas described by their radii vectores in a given time is a maximum; and made notable advances in the theory of astronomical refraction (Mec. cel.
It has been found by Sir William Herschel and others that the definition of a telescope is often improved by stopping off a part of the central area of the object-glass; but the advantage to be obtained in this way is in no case great, and anything like a reduction of the aperture to a narrow annulus is attended by a development of the external luminous rings sufficient to outweigh any improvement due to the diminished diameter of the central area.'
The diminution of the star disks with increasing aperture was observed by Sir William Herschel, and in 1823 Fraunhofer formulated the law of inverse proportionality.
The objection raised by Herschel (Light, § 703) to this comparison depends on a misconception.
Of 80 comets seen during the 20 years ending 1893, Professor Herschel found that only two, viz.
A valuable edition of the De aquis (text and translation) has been published by C. Herschel (Boston, Mass., 1899).
The name was first given by Sir John Herschel to an apparatus for measuring the heating effect of solar rays (Edin.
Sir John Herschel took as the northern boundary of the southern ocean the greatest circle which could touch the southernmost extremities of the three southern continents.
It is the birthplace of Sir William Herschel, the astronomer, of the brothers Schlegel, of Ifliand and of the historian Pertz.
Herschel wrote a full account in the Edinburgh Review), and in 1848 Du systeme social et des lois qui le regissent.
The first constructor of reflecting telescopes on a large scale, William Herschel, never published anything about his methods of casting and polishing specula, and he does not appear to have been very successful beyond specula of 18 in.
Herschel and Robinson in The Athenaeum, Nos.
Herschel, who discovered that many of them formed systems of two stars revolving round their common centre of gravity.
Herschel (and for some time Sir James South) had observed them, but their labours were eclipsed by Struve.
On the other hand, scientific men, such as Herschel, Maxwell and Stokes, who approach nature from mathematics and mechanics, and therefore from the universal laws of motion, have the opposite tendency, because they perceive that nature is not its own explanation.
About the year 1774 William Herschel, then a teacher of music in Bath, began to occupy his leisure hours with the construction of specula, and finally devoted himself entirely to their construction and use.
This form was adopted by the - elder Herschel to avoid the loss of light from reflection in the small mirror of the Newtonian telescope.
Now, if a graduated circle B B is attached to the declination axis, together with the necessary verniers or microscopes V V for reading it (see Transit Circle), so arranged that when the telescope is turned on the declination axis till its optical axis is parallel to A A the vernier reads 0° and when at right angles to A A 90°, then we can employ the readings of 2 Herschel, Phil.
For 1824 (part 3, pp. 1-412) will be found a description by Sir John Herschel and Sir James South of the equatorial telescope which they employed in their measurements of double stars.
Sir William Herschel and afterwards F.
His influence on his successors has rather lain in the general stimulus of his enthusiasm for experience, or in the success with which he represents the cause of nominalism and in certain special devices of method handed down till, through Hume or Herschel, they affected the thought of Mill.
Herschel, Peter Barlow and others, but did not receive a final explanation until after the discovery of electromagnetic induction by Faraday in 1831.
103.) 4 See the vigorous passage in Herschel, Discourse on the Study of Natural Philosophy, § 105; cf.
Two other conditions may also be postulated: one is always the elimination of the aberration on the axis; the second either the " Herschel " or " Fraunhofer condition," the latter being the best (vide supra, " Monochromatic Aberration ").
Reflector by Herschel, and later by a 13-ft.
Along with Sir John Herschel and George Peacock he laboured to raise the standard of mathematical instruction in England, and especially endeavoured to supersede the Newtonian by the Leibnitzian notation in the infinitesimal calculus.
There is more than one meaning of William Herschel discussed in the 1911 Encyclopedia.
His last subject of investigation was the motion of balloons, and the last subject on which he conversed was the newly discovered planet Herschel (Uranus).
High) are an inner spur of the Drakensberg running through the Herschel district.
As early as 1839 a scheme of public schools, drawn up by Sir John Herschel, the astronomer, came into operation, and was continued until 1865, when a more comprehensive scheme was adopted.
The change from slave to free labour proved to be advantageous to the farmers in the western provinces; an efficient educational system, which owed its initiation to Sir John Herschel, the astronomer (who lived in Cape Colony from 1834 to 1838), was adopted; Road Boards were established and did much good work; to the staple industries - the growing of wheat, the rearing of cattle and the making of wine - was added sheepraising; and by 1846 wool became the most valuable export from the country.
The latter was struck by the coincidence, and mentioned it to the Board of Visitors of the Observatory, James Challis and Sir John Herschel being present.
Herschel, at the ensuing meeting of the British Association early in September, ventured accordingly to predict that a new planet would shortly be discovered.