Theory of Colours — trans. Charles Lock Eastlake (1840)

But if the professor in this case has many reasons for respecting the dilettante, the man of science has every motive to be still more indulgent, since the amateur here is capable of contributing what may be satisfactory and useful. The sciences depend much more on experiment than art, and for mere experiment many a votary is qualified. Scientific results are arrived at by many means, and cannot dispense with many hands, many heads. Science may be communicated, the treasure may be inherited, and what is acquired by one may be appropriated by many. Hence no one perhaps ought to be reluctant to offer his contributions. How much do we not owe to accident, to mere practice, to momentary observation. All who are endowed only with habits of attention, women, children, are capable of communicating striking and true remarks.

In science it cannot therefore be required, that he who endeavours to furnish something in its aid should devote his whole life to it, should survey and investigate it in all its extent; for this, in most cases, would be a severe condition even for the initiated. But if we look through the history of science in general, especially the history of physics, we shall find that many important acquisitions have been made by single inquirers, in single departments, and very often by unprofessional observers.

To whatever direction a man may be determined by inclination or accident, whatever class of phenomena especially strike him, excite his interest, fix his attention, and occupy him, the result will still be for the advantage of science: for every new relation that comes to light, every new mode of investigation, even the imperfect attempt, even error itself is available; it may stimulate other observers and is never without its use as influencing future inquiry.

With this feeling the author himself may look back without regret on his endeavours. From this consideration he can derive some encouragement for the prosecution of the remainder of his task; and although not satisfied with the result of his efforts, yet re-assured by the sincerity of his intentions, he ventures to recommend his past and future labours to the interest of his contemporaries and posterity.

Multi pertransibunt et augebitur scientia.

[1] Plate 1, fig. 3.

[2] See Note C.

[3] Some early Italian writers, Sicillo, Occolti, Rinaldi, and others, have treated this subject in connexion with the supposed signification of colours.--T.

[4] The English technical expressions "flat" and "square" have an association of mannerism.--T

[5] Towards the close of 1806, when Weimar was occupied by Napoleon after the battle of Jena.--T.

NOTES.

NOTE A.--Par. 18.

Leonardo da Vinci observes that "a light object relieved on a dark ground appears magnified;" and again, "Objects seen at a distance appear out of proportion; this is because the light parts transmit their rays to the eye more powerfully than the dark. A woman's white head-dress once appeared to me much wider than her shoulders, owing to their being dressed in black."[1] "It is now generally admitted that the excitation produced by light is propagated on the retina a little beyond the outline of the image. Professor Plateau, of Ghent, has devoted a very interesting special memoir to the description and explanation of phenomena of this nature. See his 'Mémoire sur l'Irradiation,' published in the 11th vol. of the Transactions of the Royal Academy of Sciences at Brussels."[2]--S. F.

NOTE B.--Par. 23.

"The duration of ocular spectra produced by strongly exciting the retina, may be conveniently measured by minutes and seconds; but to ascertain the duration of more evanescent phenomena, recourse must be had to other means. The Chevalier d'Arcy (Mém. de l'Acad. des Sc. 1765,) endeavoured to ascertain the duration of the impression produced by a glowing coal in the following manner. He attached it to the circumference of a wheel, the velocity of which was gradually increased until the apparent trace of the object formed a complete circle, and then measured the duration of a revolution, which was obviously that of the impression. To ascertain the duration of a revolution it is sufficient merely to know the number of revolutions described in a given time. Recently more refined experiments of the same kind have been made by Professors Plateau and Wheatstone."--S. F.