[14] Some time before the first announcement of the discovery of sun-painting, the following extract from Sir John Herschel’s _Treatise on Light_, in the _Encyclopædia Metropolitana_, appeared in a popular work entitled _Parlour Magic_: “Strain a piece of paper or linen upon a wooden frame, and sponge it over with a solution of nitrate of silver in water; place it behind a painting upon glass, or a stained window-pane, and the light, traversing the painting or figures, will produce a copy of it upon the prepared paper or linen; those parts in which the rays were least intercepted being the shadows of the picture.” [15] In his book on Colours, Mr. Doyle informs us that divers, if not all, essential oils, as also spirits of wine, when shaken, “have a good store of bubbles, which appear adorned with various and lively colours.” He mentions also that bubbles of soap and turpentine exhibit the same colours, which “vary according to the incidence of the sight and the position of the eye;” and he had seen a glass-blower blow bubbles of glass which burst, and displayed “the varying colours of the rainbow, which were exceedingly vivid.” [16] The original idea is even attributed to Copernicus. M. Blundevile, in his _Treatise on Cosmography_, 1594, has the following passage, perhaps the most distinct recognition of authority in our language: “How prooue (prove) you that there is but one world? By the authoritie of Aristotle, who saieth that if there were any other world out of this, then the earth of that world would mooue (move) towards the centre of this world,” &c. Sir Isaac Newton, in a conversation with Conduitt, said he took “all the planets to be composed of the same matter with the earth, viz. earth, water, and stone, but variously concocted.” [17] Sir William Herschel ascertained that our solar system is advancing towards the constellation Hercules, or more accurately to a point in space whose right ascension is 245° 52′ 30″, and north polar distance 40° 22′; and that the quantity of this motion is such, that to an astronomer placed in Sirius, our sun would appear to describe an arc of little more than _a second_ every year.--_North-British Review_, No. 3. [18] See M. Arago’s researches upon this interesting subject, in _Things not generally Known_, p. 4. [19] This eloquent advocacy of the doctrine of “More Worlds than One” (referred to at p. 51) is from the author’s valuable _Outlines of Astronomy_.