Footnotes:
[1] An account of the experiments above alluded to was given in the Analyse des Travaux de la Classe des Sciences Mathématiques et Physiques de l’Institut Royal de France, pendant l’année 1815, par M. le Chev. Delambre, p. 29, &c. The colours produced by repeated reflexions from plates of silver are those of Elliptical Polarization, and are explained at great length in my paper on that subject, published in the Philosophical Transactions for 1830.
[2] As this Patent, in so far as the simple Kaleidoscope is concerned, was to a great extent infringed, it has been supposed that it was reduced in a Court of Law. The validity of the Patent was never questioned by any lawyer, or any philosopher acquainted with its theory and construction, as will appear from the opinion of four competent judges, given in the Appendix.
In a trial for the infringement of a Patent several years ago, a distinguished judge (we believe it was Judge Alderson) stated it as a fact, that the Patent for the Kaleidoscope had been set aside in a Court of Law. The party whose case was prejudiced by this erroneous assertion, applied to me for an affidavit, by which he was enabled to contradict it in Court, and remove any unfavourable impression it might have made upon the jury.
[4] See the article Accidental Colours, in the Edinburgh Encyclopædia, vol. i. p. 88.
[5] An instrument called The Improved Kaleidoscope has been recently brought out in Paris. It is merely the Telescopic Kaleidoscope deteriorated. It consists of a lens fixed at the distance of about two inches in front of the reflectors, and can therefore give symmetrical pictures of objects only at one distance, while it cannot be used as an ordinary Kaleidoscope. The instrument described in the preceding page, with a lens that can be slipped off, is a much better Kaleidoscope.
[7] When this chapter was written (1818), it was very difficult to procure glass sufficiently homogeneous for this purpose: but it can now be procured from the Glass Works of Messrs. Chance & Co., at Smethwick, near Birmingham.
[8] This light was first proposed by myself. See Edinburgh Review, April 1833, vol. lvii. p. 192.