As a practical astronomer he remains without an equal. In profound philosophy he has few superiors. By a kindly chance he can be claimed as the citizen of no one country. In very truth his is one of the few names which belong to the whole world.
FOOTNOTES:
[31] James Short, F.R.S. (1710-1768), and John Dollond, F.R.S. (1706-1761), were the most celebrated makers of telescopes of their day. The six-foot Newtonian reflectors of Short (aperture 9.4 inches), and the forty-six-inch achromatics of Dollond (aperture 3.6 inches), were highly esteemed. The Royal Observatory of Greenwich possessed, in 1765, one of each class. In a comparative trial of Short's telescope, at Greenwich, and one of Herschel's first telescopes, the latter was adjudged greatly superior.
[32] At least one of these telescopes had the principal mirror made of glass instead of metal.—Philosophical Transactions, 1803.
[33] The following extract from Fourier's Éloge of Herschel is of interest in this connection. The sum first appropriated by the king was £2,000. This was afterwards raised to £4,000, and a sum of £200 yearly was given for maintenance.
"L'histoire doit conserver à jamais la réponse de ce prince à un étranger célèbre [Lalande?] qui le remerciait des sommes considérables accordées pour les progrès de l'astronomie. 'Je fais les dépenses de la guerre,' dit le roi, 'parcequ'elles sont nécessaires; quant à celles des sciences, il m'est agréable des les ordonner; leur objet ne coûte point des larmes, et honore l'humanité.'"
Lalande's own account is a little different. He says the king exclaimed: "Ne vaut-il pas mieux employer son argent à cela qu'à faire tuer des hommes?"
[34] The memoirs on the parallaxes of stars, written by various astronomers from 1750 to 1800, were mainly directed to the improvement of the methods, or to the discovery of the parallax of some particular star. For example, Lacaille's observations of Sirius, at the Cape of Good Hope, had resulted in a parallax of 9″ for that star—a quantity over forty times too large.
[35] Herschel accepted, as did all his cotemporaries, the Newtonian or corpuscular theory of light.
[36] Thus the position of small stars critically situated in the centre, or on the edges of the nebulæ was always noted. Many of the descriptions are given in the published papers, but the publication of the diagrams would be an immense help to this branch of astronomy. D'Arrest in his reduction of Herschel's nebula observations (1856) writes: "Gewiss wäre es vom höchsten Interesse für die Entwickelung, welche hoffentlich auch dieser Zweig der beobachtenden Astronomie zukünftig erhalten wird, wenn die Herschel'schen Beobachtungen in der Ausführlichkeit in welcher sie, verschiedenen Andeutungen zufolge, handschriftlich vorhanden sind, veröffentlicht würden. Es schliesst sich dieser Wunsch in Betreff der Nebelflecken lebhaft an den an, welcher, schon vor einem Jahrzehnt nach Veröffentlichung der 400 noch unedirten star-gauges von gewichtigerer Seite her geäussert wurde." In this all must agree who have a knowledge of the direction in which we must look for advances in the difficult and important questions of the distance, the motions, and the changes of the nebulæ. Almost the only aid to be looked for from the older observations must come from such diagrams, and we may safely say that the publication of this priceless material, just as it stands, would carry our exact data back from 1833 to 1786, or no less than forty-seven years.