major's presence; for by this time the gallant officer was fully charged with indignation.

"Jacob," exclaimed he, "you must take care that I am not exposed to a repetition of this annoyance. Should any of the spinster tribe honour me with another call, inform them that I am from home, or tie up the knocker, and tell them that I am sick-dead-buried! Say anything, but spare me such another visitation!"

Had occasion required, Jacob would doubtless have acted in strict accordance with the major's injunctions, as he always considered it his duty to obey orders with military exactness. Yet the old adage of "like master, like man," was not exemplified in the case of the major and his valet; inasmuch as a little incident, which occurred on the very next day, showed that the valet by no means shared his master's antipathy to spinsters. For when Jacob, in one of his visits to the village, quite unexpectedly met with an old acquaintance of that class whom he had not seen for many years, he was greatly delighted, and very cordial greetings were exchanged. From the mutual explanations which followed, Jacob learned that his friend was and had been for many years our vicar's housekeeper-for it was no other than Annette. It was perhaps from a tender and deferential regard for the strong prejudices of his master, aggravated as they had been by the incidents just related, that Jacob refrained from mentioning to him the circumstar.ce of his acquaintance with Annette. But the reasons which could have determined Annette to maintain a similar reticence on the same subject towards the vicar, with whom she was usually very communicative, can be divined only by those who are better acquainted than ourselves with the motives which govern female breasts.

A morning came when the sun shone gloriously, and the chil

dren were delighted to know that they should that day be able to learn something of the laws by which the beautiful tints of earth and sky are produced-how the sunbeam clothes the flowers with their lovely dyes, and arrays the landscape in its variegated hues. They were summoned to the library at the accustomed hour, and found that Mr. Seymour had again caused that apartment to be darkened by having all the shutters closed. But through the hole in the shutter of the eastern window streamed a small direct beam of intense sunlight.

"I am about to repeat for your instruction," said he, "a very noted experiment of Sir Isaac Newton's. You see I have here one of the triangular pieces of glass which hang on the lustre in

the drawing-room, from which I have detached this one, to serve in place of a more perfect piece of apparatus. Now, Tom, do you hold this piece of white cardboard perpendicular to the beam of light, for I wish everybody to observe the bright circular spot of white light, which you know is an image of the sun, by reason of the same laws which gave us yesterday the image of the rose, when its rays passed through a small opening. Observe what happens when I place the triangular piece of glass lengthways over the opening in the shutter. The white spot is gone from the cardboard; but if Tom will hold it a little higher, you will see that we have got something else instead."

"What splendid colours!" cried several voices simultaneously, as the prismatic spectrum fell on the cardboard.

Mr. Seymour explained that the elongated patch of varied colours was the image of the sun drawn out by the glass refracting the differently coloured rays of the sunlight in various degrees.

"You have, no doubt, been accustomed to think of the light of the sun as something simple and uncompounded, whereas this experiment is sufficient to show that every ray of sunshine consists of an infinity of differently coloured rays, which the little piece of glass has the power of separating from each other."

Louisa here inquired how many colours there might be in the image on the cardboard.

"It is usual,” said Mr. Seymour, in reply, "to reckon seven distinct colours in the 'solar spectrum,' as this image is called. The names given to these are red, orange, yellow, green, blue, indigo, and violet."

"I see all these!" cried Louisa.

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"But observe that they graduate into each other, so that there are portions of the spectrum which cannot be said properly to correspond with any one of these names. You observe a colour between the green and blue, which cannot be called by either name separately. The orange is really a similar transition tint between the yellow and the red; and although we have a distinct name for this colour, we have none for an indefinite number of intermediate hues which the eye readily distinguishes; so that the colours are not in reality seven, but are infinitely numerous."

Fanny asked if the colours did not in some way come out of the glass, for she had often seen colours like these in the lustre.

THE SOLAR SPECTRUM.

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"The colours you have seen, my dear, are formed precisely In this way, and if you placed your eye in the position of the cardboard, you would see such colours on looking towards the glass. But you will presently be convinced that the colours cannot be derived in any way from the glass, but belong to the light itself; for you will see that when we mix the colours together again, we shall reproduce colourless light; but although there are means of doing this with the coloured rays you see on the cardboard, I will obtain white by mixing colours in a simpler way. Before I open the shutters I wish you to observe that the red end of the spectrum is nearer to the position of the unrefracted image of the sun; hence the red rays are spoken of as the 'least refrangible,' and the violet as the 'most refrangible.' The shutters having been opened, Mr. Seymour produced a

Orange 27.

Yellow 40.

Green 60.

Blue 60.

Indigo 48.

circular disc of cardboard, on which sectors of vividly coloured papers had been pasted of the colours indicated in Fig. 26, which also shows by the numbers the sizes of the sectors - the entire edge of the circle being supposed to be divided into 360 equal parts. It was explained. that the space taken up by each colour was assigned so that the disc might have as nearly as possible the same proportion of each colour as the solar spectrum. A pin having been put through the centre of the disc, it was thus attached to a piece of wood, and made to rotate rapidly in an upright position by a touch of the finger. When the disc was in very rapid movement, the colours all became invisible, and the face of the disc appeared to be light grey, almost white; to the no small astonishment of the juvenile party.

Fig. 26.

"You will all understand from our former experiments with the thaumatrope that each colour in the revolving disc leaves its own impression on the retina; so that if only the red sector were present, we should have the appearance of a paler but uniformly red disc, and so on. And as the same is true of each of the colours, the result is that the effect of one is covered by that of

the other, so that the colours are virtually mixed in the eye, and they produce, as you see, the sensation of white."

This composition of white light by variously coloured rays was perfectly understood, and greatly delighted the youthful specta tors; but as the effect required a very rapid spinning of the disc, which was only maintained a very short time, Mr. Seymour adopted an expedient which permitted a more leisurely examination of this interesting and instructive phenomenon. He attached the disc to the upper part of a large humming-top, and when this was set in motion, the requisite rapidity was maintained for several minutes. Mr. Seymour now presented the children with several "colour tops," as they are called, which he said would instruct them in the formation of various tints by the mixing of different colours in precisely the same manner as in their experiment of the coloured disc.

Here we may mention that Tom subsequently constructed by himself a disc on a larger scale, in which the alternation of the coloured sectors was repeated several times; and by making experiments with various proportions of the coloured papers he used, he succeeded at length in so adjusting the colours, that the resulting tint was very nearly white, or, at least, no one colour could be said to predominate. Tom learnt on the present occasion that the reason why the impression resulting from the mixture of the tints was not perfectly white was partly the difficulty of proportioning the coloured surfaces, but chiefly because no pigments we possess are of a perfectly pure colour. And in reply to a question of his as to whether red, blue, yellow, &c., paint would, when mixed together, form white, Mr. Seymour told him that the mixture of pigments introduced another class of effects.

"If you will arrange one of these colour-tops so that red and green may be mixed in the eye, you will obtain a neutral or grey tint; but if you take a piece of transparent red glass, and put over it a piece of green glass, you will find, on looking through the two, that you have not added green to red, but that the light which passes through consists of those coloured rays which can pass through both glasses; and as a glass of a pure red colour would stop all but red rays, and a similar green glass all green rays, the superposition of two such glasses would be opacity. But the colouring matter in glass, although allowing rays of a certain refrangibility to pass more abundantly, always permits