above, and with its ale and feptum below fixed in the incifion. A little terra japonica is foftened with water, and being fpread on flips of cloth, five or fix of thefe are placed over each other, to fecure the joining. No other dreffing but this cement is ufed for four days. It is then removed, and cloths dipped in ghee (a kind of butter) are applied. The connecting flips of fhin are divided about the 25th day, when a little more diflection is neceflary to improve the appearance of the new nofe. For five or fix days after the operation, the patient is made to lie on his back; and, on the tenth day, bits of foft cloth are put into the nofirils, to keep them fufficiently open. This operation is very generally fuccefsful. The artificial nofe is fecure, and looks nearly as well as the natural one; nor is the fcar on the forehead very obfervable after a length of time. of the window-fhutter, fall at an angle of about 70° upon a fheet of very fine white paper, I placed a burning wax candle in fuch a pofition, that its rays fell upon the fame paper, and as near as I could guess, in the line of reflection of the rays of day-light from without; when interpofing a cylinder of wood, about half an inch in diameter, before the centre of the paper, and at the dif tance of about two inches from its furface, I was much furprized to find that the two shadows projected by the cylinder upon the paper, inftead of being merely fhades without colour, as I expected, the one of them, that which, correfponding with the beam of day-light, was illuminated by the candle, was yel low; while the other, correfponding to the light of the candle, and confequently illuminated by the light of the heavens, was of the most beautiful blue that it is poffible to imagine. This appearance, which was not only unexpected, but was really in itfelf in the highest degree striking and beautiful, I found, upon repeated trials, and after varying the experiment in every way I could think of, to be fo perfectly permanent, that it is abfolutely inpoffible to produce two fhadows at the fame time from the fame body, the one anfwering to a beam of day-light, and the other to the light of a candle or lamp, without these fhadows being coloured, the one yellow, and the other blue. The experiment may very easily be made at any time by day, and almoft in any place, and even by a perfon not in the leaft degree verfed in experimental researches. Nothing more is neceffary for that purpofe than to take a burning can dle into a darkened room in the day time, time, and open one of the windowthutters a little, about half or three quarters of an inch for inftance; when the candle being placed upon a table or ftand, or given to an affiftant to hold, in fuch a fituation that the rays from the candle may meet thofe of day-light from without, at an angle of about 40°, at the furface of a fheet of white paper, held in a proper pofition to receive them,any folid opaque body, a cylinder, or even a finger, held before the paper, at the distance of two or three inches, will project two fhadows upon the paper, the one blue, and the other yellow. If the candle be brought nearer to the paper, the blue fhadow will become of a deeper hue, and the yellow fhadow will gradually grow fainter; but if it be removed farther off, the yellow fhadow will become of a deeper colour, and the blue fhadow will become fainter; and the candle remaining ftationary in the fame place, the fame varieties in the ftrength of the tints of the coloured fhadows may be produced merely by opening the window-fhutter a little more or lefs, and rendering the illumination of the paper by the light from without ftronger or weaker. By either of thefe means, the coloured fhadows may be made to pafs through all the gradations of fhade, from the deepeft to the lighteft, and vice verfa; and it is not a little amufing to fee fhadows, thus glowing with all the brilliancy of the pureft and most intenfe prifmatic colours, then paffing fuddenly through all the varieties of fhade, preferving in all the moft perfect purity of tint, growing ftronger and fainter, and vanifhing and returning at command. With refpect to the caufes of the colours of thefe fhadows, there is no doubt but they arife from the dif ferent qualities of the light by which they are illuminated; but how they are produced, does not appear to me fo evident. That the fhadow correfponding to the beam of daylight, which is illuminated by the yellow light of a candle, fhould be of a yellowish hue, is not furprifing: but why is the fhadow correfponding to the light of the candle, and which is illuminated by no other light than the apparently white light of the heavens, blue? I at first thought that it might arife from the bluenefs of the fky; but finding that the broad day-light, reflected from the roof a neighbouring houfe covered with the whiteft new fallen fnow, produced the fame blue colour, and, if poffible, of a still more beautiful tint, I was obliged to abandon that opinion. To afcertain with fome degree of precifion the real colour of the light emitted by a candle, I placed a lighted wax candle, well trimmed, in the open air, at mid-day, at a time when the ground was deeply covered with new fallen fnow, and the heavens were overfpread with white clouds; when the flame of the candle, far from being white, as it appears to be when viewed by night, was evidently of a very decided yellow colour, not even approaching to whitenefs. The flame of an Argand's lamp, expofed at the fame time in the open air, appeared to be of the fame yellow hue. But the moft ftriking manner of fhewing the yellow hue of the light emitted by lamps and candles, is by expofing them in the direct rays of a bright meridian fun. In that fituation the flame of an Argand's lamp, burning with its greatest brilliancy, appears in the form of a dead yellow femi-transparent fmoke. How tranfcendently pure and inconceivably bright the rays of the fun are, when compared to the light of any of our artificial illuminators, may be gathered from the refult of this experiment. It appearing to me very probable, that the difference in the whitenefs of the two kinds of light, which were the fubjects of the foregoing experiments, might, fome how or other, be the occafion of the different colours of the fhadows, I attempted to produce the fame effects by employing two artificial lights of different colours; and in this I fucceeded completely. In a room previously darkened, the light from two burning wax candles being made to fall upon the white paper at a proper angle, in order to form two diftinct fhadows of the cylinder, thefe fhadows were found not to be in the leaft coloured; but upon interpofing a pane of yellow glafs, approaching to a faint orange colour, before one of the candles, one of the fhadows immediately became yellow, and the other blue. When two Argand's lamps were made ufe of infiead of the candles, the refult was the fame; the fhadows were conftantly and very deeply coloured, the one yellow approaching to orange, and the other blue approaching to green. I imagined that the greenish caft of this blue colour was owing either to the want of whiteness of the one light, or to the orange hue of the other, which it acquired from the glafs. When equal panes of the fame yellow glafs were interpofed before both the lights, the white paper took an orange hue, but the fhadows were, to all appearance, without the leaft tinge of colour; but to pares of the yellow glafs being af terwards interpofed before one of the lights, while only one pane remained before the other, the colours of the fhadows immediately returned. The refult of thefe experiments having confirmed my fufpicions, that the colours of the fhadows arole from the different degrees of white nels of the two lights, I now endea voured, by bringing day-light to be of the fame yellow tinge with candle-light, by the interpofition of fleets of coloured glafs, to prevent the fhadows being coloured when day-light and candle-light were to gether the fubjects of the experiment; and in this I fucceeded. I was even able to reverfe the colours of the fhadows, by caufing the daylight to be of a deeper yellow that the candle-light. In the course of thefe experiments I obferved, that different thades of yellow given to the day-light produced very different and often quite unexpected effects: thus one freet of the yellow glass interpofed before the beam of daylight, changed the yellow fhadow to a lively violet colour, and the blue fhadow to a light green; two fhcets of the fame glafs nearly de ftroyed the colours of both the fhadows; and three fheets changed the fhadow which was originally vellow to blue, and that which was blue to a purplish yellow colour. When the beam of day-light was made to país through a fleet of blue glafs, the colours of the fhadows, the yellow as well as the blue, were improved and rendered in the higheft degree clear and brilliant; bat when the blue glafs was placed be fore the candle, the colours of the fhadows were very much impair ed. la In order to see what would be to a small arm of wood, or of metal, the confequence of rendering the projecting forward from the bottom candle-light of a still deeper yellow, of the board for that purpofe. A I interpofed before it a fheet of fall ftand, capable of being higher yellow or rather orange-coloured or lower as the occafion requires, glas, when a very unexpected and fhould likewife be provided for fupmost beautiful appearance took porting the candle; and if the board place; the colour of the yellow with the paper faftened upon it be hadow was changed to orange, the furrounded with a broad black blue fhadow remained unchanged, frame, the experiments will be fo and the whole furface of the paper much the more ftriking and beautiappeared to be tinged of a moft ful. For ftill greater convenience, beautiful violet colour, approaching I have added two other ftands, for to a light crimson or pink; almost holding the coloured glafs through exactly the fame hue as I have often which the light is occafionally made obferved the diftant fnowy moun- to pafs, in its way to the white furtains and valleys of the Alps to take face upon which the fhadows are about funfet. Is it not more than projected. It will be hardly neprobable, that this hue is in both cellary to add, that in order to the cafes produced by nearly the fame experiments appearing to the greatcombinations of coloured light? in eft advantage, all light, which is the one cafe, it is the white fnow not abfolutely neceffary to the exilluminated at the fame time by the periment, must be carefully fhut pureft light of the heavens, and by out. the deep yellow rays from the weft; and in the other, it is the white paper illuminated by broad day-light, and by the rays from a burning candle, rendered ftill more yellow by being tranfmitted through the yellow glafs. The beautiful violet colour which spreads itself over the furface of the paper will appear to the greatest advantage, if the pane of orange-coloured glafs be held in fuch a manner before the candle, that only a part of the paper, half of it for inftance, be affected by it, the other half of it remaining white. To make thefe experiments with more convenience, the paper, which may be about 8 or 10 inches fquare, fhould be pafted or glued down upon a flat piece of board, furnished with a ball and focket upon the hinder fide of it, and mounted upon a stand; and the cylinder fhould be faftened Having fitted up a little apparatus according to the above directions, merely for the purpofe of profecuting thefe inquiries refpecting the coloured fhadows, I proceeded to make a great variety of experi ments, fome with pointed views, and others quite at random, and merely in hopes of making fome accidental difcovery that might lead to a knowledge of the caules of appearances which ftill feemed to me to be enveloped in much obfcurity and uncertainty, Having found that the fhadows correfponding to two like wax candles were coloured, the one blue, and the other yellow, by interpofing a fheet of yellow glats before one of them; I now tried what the effeet would be when blue glafs was made ufe of inftead of yellow, and I found it to be the fame; the shadows were ftill coloured, the one blue, blue, and the other yellow, with the difference, however, that the colours of the shadows were reverfed, that which, with the yellow glafs, was before yellow being now blue, and that which was blue being yellow. I afterwards tried a glafs of a bright amethyst colour, and was furprized to find that the fhadows ftill continued to be coloured blue and yellow. The yellow, it is true, had a dirty purple caft; but the blue, though a little inclining to green, was nevertheless a clean, bright, decided colour. Having no other coloured glass at hand to push these particular inquiries farther, I now removed the candles, and opened two holes in the upper parts of the windowflutters of two neighbouring windows, I let into the room from above two beams of light from different parts of the heavens, and placing the inftrument in fuch a manner that two diftinét fhadows were projected by the cylinder upon the paper, I was entertained by a fucceffion of very amufing appearances. The fhadows were tinged with an infinite variety of the most unexpected, and often moft beautiful colours, which continually varying, fometimes flowly, and fometimes with inconceivable rapidity, abfolutely fafcinated the eves, and commanding the most eager attention, afforded an enjoyment as new as it was bewitching. It was a windy day, with flying clouds, and it feemed as if every cloud that paffed brought with it another complete fucceffion of varying hues, and moft harmonious tints. If any colours could be faid to predominate it was purples; but all the varieties of browns, and, almost all the other colours I ever remembered to have feen, appeared in their turns, and there were even colours which feemed to me to be perfectly new. Reflecting upon the great variety of colours observed in these last experiments, many of which did not appear to have the leaft relation to the apparent colours of the light by which they were produced, I began to fufpect that the colours of the fhadows might, in many cafes, notwithftanding their apparent brilli ancy, be merely an optical deception, owing to contraft, or to fome effect of the other neighbouring colours upon the eye. To determine this fact by a direct experiment, I proceeded in the following manner. Having, by making ufe of a flat ruler inftead of the cylinder, contrived to render the fhadows much broader, I fhut out of the room every ray of day-light, and prepared to make the experiment with two Argand's lamps, well trimmed, and which were both made to burn with the greateft poffible brilliancy; and having affured myfelf that the light they emitted was precifely of the fame colour, by the fhadows being perfectly colourless which were projected upon the white paper, I directed a tube about 12 inches long, and near an inch in diameter, lined with black paper, against the centre of one of the broad fhadows; and looking through this tube with one eye, while the other was clofed, I kept my attention fixed upon the fhadow, while an afliftant repeatedly interpofed a fleet of yellow glafs before the lamp whofe fight correfponded to the fhadow I obferved, and as often removed it. The refult of the experiment was very ftriking, and fully confirmed my ful picions with refpect to the fallacy ધર્મ |