In giving an account of these experiments to M. Biot on the 6th of March 1815, I remarked to him, “that when the angle of incidence (on the plates of silver) was about 85° or 86°, and the plates almost in contact, and inclined at a very small angle, the two series of reflected images appeared at once in the form of two curves; and that the succession of splendid colours formed a phenomenon which I had no doubt would be considered, by every person who saw it to advantage, as one of the most beautiful in optics.” These experiments were afterwards repeated with more perfectly polished plates of different metals, and the effects were proportionally more brilliant: but notwithstanding the beauty arising from the multiplication of the images, and the additional splendour which was communicated to the picture by the richness of the polarized tints, it was wholly destitute of symmetry, as I was then ignorant of those positions for the eye and the objects, which are absolutely necessary to produce that magical union of parts, and that mathematical symmetry throughout the whole picture, which, independently of all colouring, give to the visions of the Kaleidoscope the peculiar charm which distinguishes them from all artificial creations.[1] [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. Although I had thus combined two plain mirrors, so as to produce highly pleasing effects, from the multiplication and circular arrangement of the images of objects placed at a distance from their extremities, yet I had scarcely made a step towards the invention of the Kaleidoscope. The effects, however, which I had observed, were sufficient to prepare me for taking advantage of any suggestion which experiment might afterwards throw in the way.