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and disappointment at being baffled by the watchful guardians of the unhatched queen, from whom the hoarse sound comes. In the afternoon of the same day the last mentioned female left her cell. I saw her come forth in majesty, finely and delicately formed, but smaller than the other. She immediately retired within a cluster of bees, and I lost sight of her. Next morning, on opening the shutter of the hive, I perceived the youngest queen rushing apparently in great terror over the face of the comb, and turning round the edge of it to the other side; and in the next moment the other queen was seen pursuing with equal rapidity. I now fully expected to witness Huber's combat of queens, and was about to wheel round the hive on its pivot, to inspect their proceedings on the other side, when business called me off. I returned in half an hour, thinking I might yet be in at the death, but found all was over ! The young queen was lying on the alighting-board on her back, in the pangs of death, newly brought out by the bees, and doubtless the victim of the elder queen.

I observe two circumstances respecting this last queen, one of which agrees perfectly with the experience of Huber, while the other is at variance with it. While the young queen remained a virgin, not the slightest respect was paid her by the bees; not one gave her food, she was obliged to help herself, and in crossing towards the honey-cells, she had to scramble over the crowd, not an individual of which would get out of her way, or seemed to care whether she fed or starved. But no sooner did she begin laying than the scene was changed, and complaisance, respect and attention, became the order of the day; one after another extended the proboscis with food, and at every step of her progress a circle was formed round her by her admiring people. The other circumstance, and which varies from the experience of Huber, respects the sound emitted by the queens. He says that the workers form no guard around the cells of artificial queens,—that these are perfectly mute, and he makes several remarks by way of accounting for it. The above experiment completely contradicts this. The cell of the young queen was guarded most vigilantly, and both emitted the sounds alluded to, perhaps once every minute, for several hours together.

Experiment II.-This experiment, which was entirely practical, and consisted in turning to account the result of the first experiment, respected the formation of artificial swarms, an expedient, in my opinion, never to be resorted to, but in such cases of necessity as that I am about to detail. From the first to the third week of June my hives had all thrown their top-swarms; but instead of throwing their second in ten or twelve days thereafter, as is generally the case, four of them had not cast nearly three weeks after. This was probably owing to the unfavourable state of the weather, which, by delaying the swarming, had furnished the reigning queen with an opportunity of putting to death one or two of her intended successors. In these circumstances, from the crowded state of the hive, a mass of bees as large as a man's head hung from the alighting-board of each hive; a sight grievous to the Apiarian, as these outliers are quite idle. Determined to avail myself of Schirach's and Huber's discoveries, I cut out of the Mirror-hive a piece of comb about three inches square, containing eggs and worms, and fixed it in an old hive full of empty comb. I then removed out of sight one of the hives which had an outlying, or rather outhanging, mass on its alighting-board, instantly clapped down in its place on said board the empty hive, and forced the idlers to enter. They made a tremendous noise, and seemed disconcerted at finding, instead of the rich combs they had hitherto been familiar with, nothing but empty cells. This agitation was kept up all day by the continued arrival of the bees belonging to the original hive, who had been abroad when their habitation was changed, and who now added greatly to the population. At noon next day I inspected the new establishment (a leaf-hive of Huber), and found, to my satisfaction, the foundations of three queen-cells laid in the small piece of brood-comb I had given them. In due time a queen was hatched,—the hive prospered, and at the end of the season I took from it four and a half pints of honey. Finding this trial succeed so well, I instantly fell to work with two more in similar circumstances, and with the same success. One of these died about a month after, but from causes which had no connection with the experiment; the other I kept over winter, and it has now swarmed, (July 1. 1823).

I had still another which hung out, and from this also I forced a cast, but by a method which has been often adopted by others. I carried the full hive into a dark place, turned it up, placed an empty hive over it, mouth to mouth, and drove it partially. Perceiving that half the bees had gone up, and knowing that in these cases the queen is always among the foremost, I immediately replaced the old hive in its former station, and carried the new one, containing the queen, to a little distance. As the old hive had plenty of eggs and young brood, the bees were at no loss to procure another queen; and the new one having a queen, proceeded to work in all respects as a natural young swarm. The old one I kept over winter, and it east this sunanner.

ART. V.-On the Refractive and Dispersive Power of different Species of Glass, in reference to the improvement of Achromatic Telescopes, with an Account of the Lines or Streaks which cross the Spectrum. By Joseph FRAUENHofer of Munich. Concluded from Vol. IX, p. 299.

As the lines of the spectrum are seen with every refracting substance of uniform density, I have employed this circumstance for determining the index of refraction of any substance for each coloured ray. This could be done with the greater exactness, as most of the lines are very distinct and well marked. For this purpose, I selected the largest lines, because with substances of low refractive power, or with prisms of small refracting angles, the lines of less magnitude could scarcely be perceived with a strong magnifying power. The lines which I chose were those marked B, C, D, E, F, G, H, in Fig. 5. of Plate VII. (Vol. IX.) I made no use of the line b, because it is too near F, and I endeavoured to use the middle one between D and F. It is not practicable to measure large arcs, such as BH, but only small ones like BC, CD, because, in order to see the lines of the different colours distinctly, the eye-glass requires to be displaced.

The following Table contains the measures of the angles obtained from different kinds of glass, and other refracting subStanceS.

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In order to measure these angles, I employed the same theodolite which I have already mentioned. The measures were taken six times. The distance of the theodolite from the window of the dark room into which the light entered, was only 24 feet. The correction of the angle to arising from the distance 4.25 inches of the prism from the axis of the theodolite, would have been very considerable. In order to avoid the uncertainty which arises from a great correction, I determined the angle a for the light of a lamp, as the rays D, Fig. 5. and R, Fig. 4. Plate VII. Vol. IX, have the same refrangibility. In this case the lamp was at a distance of 692 feet; the correction of a was

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very small; and, with the prism with which I made these experiments, it was only 40".5 for water. I have measured, then, only the arcs BC, CD, DE, &c. The corrections are small, and consequently very exact. With the prism they amounted, for BC only to 2".5, for CD to 6".5, and for DE to 8". All the angles in the preceding Table have received this correction. Calling a the angle of the incident ray, 6 the angle of the emergent ray, ! the angle of the prism, and n the index of refraction, we obtain

70 - V (sin g + cos & sin z)* + (sin J sin *] - sin ob If the angle of the incident ray is equal to the angle of the emergent ray, and if * is the angle which the incident ray forms with the emergent ray, we shall have sink (k+4). sin # 4. This last expression for n will not be rigorously correct in substances with a great dispersive power, and for an emergent ray, the angle of which is not equal to that of the incident ray, for the latter cannot be so, excepting to only one of the emergent rays, such as that at D, on the supposition that the prism does not change its place. In making use of the last Formula for calculating the indices of refraction with great accuracy, I only measured the arcs BC, CD, DE, &c. when the distance of the two lines was the smallest. But this distance corresponds only to two lines of the spectrum, if a ray in the middle of them makes the smallest angle with the incident ray. When I measured, for example, the arc GH, the place of the prism was such, that a ray, nearly in the middle between G and H, formed the same angle with the prism that the incident ray did. The prism has this position when the angle of refraction of this mean ray is a minimum. By the help of the telescope, and by turning the plane on which the prism rests, this position may be easily found with the greatest exactness. With substances of a less dispersive power, or with prisms of a smaller angle, the same care is not requisite to obtain this degree of accuracy. Calling En the index of refraction for the ray E, we have

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