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hibited to our wondering view whole dynasties of monarchs of whom history is silent. Mr. Fellowes very sensibly tickets his coins with the name of the place where they were severally found, on purpose to make them serve as historic records; he seems to consider them of the Homeric age, or thereabouts, and remarks that, like fossils in geology, they may be useful in indicating a date and a name to their different localities.'

Addison's Cynthio sarcastically observes that 'to have a relish for ancient coins it seems necessary to have a contempt for the modern.' And small, in truth, can be our self-congratulations on the score of coinage.

"O, when shall Britain, conscious of her claim, Stand emulous of Greek and Roman fame?'

The perfection of machinery is attained by us, but our dies are below mediocrity. It is true that money must stack or pile for commercial purposes, but even the flattest jetton might be wedded to an elegant device: it is true that rapidity of mintage is a desirable object, but it may be equally well exerted on a good die, as on a bad one. Mr. Akerman who understands these matters thoroughly, and has done so much for his favorite study says with scornful brevity:

'Of the coins of our monarchs, succeeding Queen Anne, it will scarcely be necessary to speak, except to notice their utter insignificance both in design and execution.'

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But Hans has pointed proudly to his dear father"For that I fought-your brother his sword against it drew;

For that have I done battle, for that your brother slew!"

The stranger glances downward, then in Hans' face does gaze

He strives to lift his arm, but that arm he cannot raise

"And didst thou slay him yonder, in rightful war it fared?

And wilt thou now forgive me? Come, Hans, I am prepared!"

JANET W. WILKINSON.

SONNET TO A LADY PRAYING.

From the Metropolitan. WHEN on thine eyes of holy light I gaze, And see them gently, with imploring grace, Turn to that fount of still more holy light, Thy lip full ripe with extasy of praise, By tears of rapture made more purely bright, And all the expressive silence of thy face, And move, in beauty equal to thine own, My soul then longs from life to spread its wing, Of Him whose praise no lip less pure should sing. To realms of glory, the eternal throne O! since within thy hallowed bosom lie All we should learn, the holy secret give; Teach me to live, that I may never die; Teach me to die, that I through death may live!

BRITISH ASSOCIATION.

From the Literary Gazette.

ing and valuable matter from the reports made to this Association, at its late session at Cork and we can assure our readers of profit from the perusal.-ED.

The general Committee met at 3 o'clock, Aug. 16th-the Earl of Rosse in the chair-and a good attendance of members, including the Marquis of Northampton, Sir W. Hamilton, Professor Robinson of Armagh, Col. Sabine, &c. &c.

This report was adopted; and Prof. Robinson moved the thanks of the committee to government for the 10001. grant, taking occasion to We have taken some pains to extract interest-caille in the southern hemisphere was only illustrate the importance of the subject. Lasecond to Bradley in the north; and the services of both to astronomy were of interest to the whole world. But Lacaille's labors had remained a dead letter till this work was undertaken. He stated that the mere observation of a star might be made in two seconds, which it would require two hours to calculate; and thus, except for what the British Association had done in this respect, and now with the liberal aid of government, the whole was lost to the lovers of science. With regard to Lalande's Histoire Céleste, Bonaparte, who was no mean judge of what such services deserved, created him a peer of France, with a pension; and now we had gone far beyond what he had accomplished, by reducing his observations. Whenever science applied to government for assistance on real grounds, he had always found the answer such as to deserve acknowledgments similar to those he now moved.

The minutes of the last two meetings were read and confirmed; also a complimentary letter from the Italian Society of Sciences at Modena.

The report of the council was read by Col. Sabine.

number to be printed had not been decided upon. This will be determined at the present meeting, and a farther sum applied for, to procure the requisite preface, for press corrections, and other contingencies. The catalogue will include nearly 10,000 stars, and will be of high value to all astronomers.

Sir W. Hamilton expressed gratitude for the extreme service already practically rendered; and he looked forward to the completion of the work with great interest. He was certain that, even if there had been no other fruit of the existence of the British Association, this important contribution to astronomical science would entitle it to the memory of all ages.

The principal point of the report of the council referred to the resolution passed at Manchester, that application be made to government to undertake the publication of the Catalogue of the Stars in the southern hemisphere, which Mathematical and Physical Science.-Dr. have been reduced and prepared for publication Robinson read a brief report accounting for the at the expense of the British Association, and delay of printing the British Association catathat the president and council of the Royal logue of stars. The whole of the reductions, Society be requested to support the application. with a few trifling exceptions, have been made; A report was accordingly drawn up and sub- and no farther expenditure on this account will mitted to the above officers of the Royal So-be required. The cause of delay was, that the ciety, and co-operation asked: they declined to accede, and the application was transmitted to Sir R. Peel by the British Association alone. The reply of the lords of the treasury expressed regret that they were not originally apprised of the intention of embarking in the work in question, or of the probability of government being called upon for aid, and stated the inconvenience of being required to defray expenses of works already commenced without any previous consideration or concurrence of their lordships, and asked for information as to the circumstances which have rendered the funds of the British Association incompetent to complete the work. This was done by showing the large pecuniary grants already made for scientific inquiries by the Association, the sums for which they are now liable, and likely to be immediately called upon to disburse, &c. The result was a treasury authority for an issue of 1000l. towards printing the copies of the reduced Catalogue of Stars of Lalande and Lacaille. The council congratulated the general committee on the ready disposition which her Majesty's government has Prof. Lloyd stated that this physical optical shown to receive favorably and to comply with problem had hitherto baffled theory. He had the recommendation thus made by the British been engaged in its investigation, but he could Association on the behalf of science. Another not as yet boast of success. He thought the point was, the arrangements made at the ob- solution depends on assuming that the ether servatory at Kew. Persons have been appointed varies in imperceptible degrees, instead of terto take charge-a regular meteorological regis- minating abruptly on the metal, constituting an ter was commenced, under the superintendence indefinite number of layers indefinitely near to of Prof. Wheatstone, in Nov. last-a self-regis- each other. The ray of light varies with every tering meteorological apparatus, which we have varying portion of the medium; and, at each already described, has been deposited there-infinitesimal change, a portion of the wave is and an electrical apparatus established in the cupola by private subscription. Records of these will be submitted in the course of the meeting.

Prof. Powell's communication contained a list of various substances which exhibit the phenomenon of elliptical polarization. As far as his observations had yet gone, it seems restricted to metallic substances and their compounds. It would be desirable to determine the metallic proportion of the latter, and the nature of the elliptical vibration for each.

reflected, and again the next portion-an infinite sum of indefinitely small reflected waves resulting and producing the phenomenon. A difficulty, however, occurring, forced him into a second

1843.]

THE BRITISH ASSOCIATION.

hypothesis, still retaining the sum of infinitesimal reflections, but assuming that the ether does terminate abruptly on the metal, although not on the successive layers.*

411

of Copernicus. It is to be inferred, then, that
the chemical or tithonic power of moonlight is
solar light, as if these rays were absorbed on the
far less, in proportion to brilliancy, than that of
surface of the moon.

Meteorological Observations at Plymouth.-
The first series of
Mr. Snow Harris gave a most satisfactory ac-
count of his stewardship.
tabulated results were from Whewell's anemo-
meter, which windgauge Mr. Harris has greatly
improved, and from which he expected to get an

Prof. Kane submitted to the section Prof. Draper's proofs of the newly discovered property of light. The subject treated was chlorine gas. That a change is produced therein by exposure to the solar rays is well known; but the novelty disclosed is, that the gas absorbs the rays, or that they become latent, altering the character of the gas. After exposure to the sunbeams, chlorine gas, its electro-negative proper-integral of the wind, the direction and intensity ties being increased thereby, unites readily with hydrogen. This state Prof. Draper terms the tithonic, and has given the same title to the ray of light which he says is absorbed, and which corresponds in refrangibility with the indigo ray. Two glass tubes of chlorine were mixed with hydrogen, the chlorine of the one having been previously exposed and tithonised, that of the other made and kept in the dark. The mixed gases were carefully placed in a beam of light admitted at a window, the tithonised chlorine instantly united with the hydrogen, the untithonised not; but becoming slowly tithonised by the exposure, did at last combine with its hydrogen. This exaltation of the electro-negative properties of chlorine is not temporary; the change is permanent; and its nature is said to be the absorption of the tithonic ray, similar to the disappearance of heat in water to produce ebullition. If the disturbance were merely molecular, it would be transient, but this is not the case; for when once the gas is tithonised, it never loses it; the electro-negative property of the chlorine is permanently increased.†

in a given time. The observations had been
continued for two years, and the first conclusion
to be drawn was, that the resultant of the cur-
Mr. Ostler's
rent at Plymouth resembled a trade-wind from
south to north; second, that the rate of the cur-
rent was five miles an hour.
anemometer will not register small forces, which
is a desideratum; but the mean hourly pressure
obtained from it was a result of interest. Both
the instruments have greatly advanced in useful-
ness since taken up by the British Association;
but they are far from perfect yet. The series of
hourly observations for the barometer, thermo-
meter, and hygrometer, have been extraordinary
for the last year to Christmas 1842. They have
been continued now for five years, and projected
in curves; but the remarkable fact is, that the
curve for 1842 is very nearly the mean of the
whole. The connection between the intensity
of the wind and the oscillation ef the barometer
Mr. Harris proposes to con-
is also striking,-intensity low, barometer high,
and vice versa.
cially in regard to Whewell's windgauge, which
tinue the observations to the end of 1843, espe-
Mr. H. thought possible to make as perfect as a
The final report will be
chronometer, and he asks for a farther small
grant: the instruments at the end of 1843 to be
deposited at Kew.

Dr. Robinson mentioned a circumstance
which appeared to him to bear out the views of
the absorption of rays from the solar light. He
had hoped to succeed in obtaining accurate de-
lineations of the irregularities of the lunar sur-ready for York next year.
face by means of the daguerreotype process.
He had prepared a plate after the process of
Claudet, and placed it in the focus of a telescope
directed to the moon. The light was so intense,
that the eye could scarcely be employed to ad-
just the plate; and Dr. Robinson thought there
would be no difficulty in obtaining a correct re-
presentation of Copernicus. There was also
attached to the telescope a clock-movement, so
accurate that no variation of position could oc-
cur. Notwithstanding this, and after an exposure
of half an hour, there was on the plate no trace

Prof. Lloyd read an extract from a letter which he had received from Mr. Ostler, communicating that he had effected improvements in his anemometer, whereby he could obtain very superior records. He had projected a new form of vane, which greatly reduced the oscillation; and he had doubled the size of the pressure-plate, which gave smaller observations, and yet it was not too large for hurricanes.

Prof. Lloyd described the present method of representing physical results, and the difficulty points obtained. He proposed the bisecting the of connecting by a regular curve the series of interval of these by a new series of points, the connecting line of which, avoiding the excessive points and steering a mean course, would be the true curve and the nearest approximation to ex

* Our readers will remember the interesting dis-
cussions on the theories of light which rendered
Sec. A. at Manchester A. 1. There were present
then flint and steel advocates of opposite views;
but this year unanimity of opinion seems to pre-act graphical representation.
vail to a considerable extent; and therefore sec-
tional discussion is less interesting and profitable.
This arises, doubtless, from the absence of many of
the peers of science already noticed and it per-
vades most of the Sections.-Ed. L. G.

The absorption of heat by ice changes its
character permanently, and alters, moreover, its
specific gravity: may not a like absorption of the
tithonic" ray produce a new form of chlorine gas,
which the testing its specific gravity may develop?
-Ed. L. G.

Mr. Hutchinson's new theory may briefly be described as the resultant of the velocities of the revolving motions of the earth on its axis and in its orbit. The accordance or opposition of which, and their several relations to each other, being considered sufficient to account for atmospheric variations, diurnal atmospheric tides, barometric alternations, the annual maxima of Humboldt, &c. &c.

Mr. S. Harris said, that Mr. Hutchinson's

theory was ingenious and worthy of attention. | to the surface of the glass. Although the result It would be curious to see what relation to phy sical forces the orbitual and diurnal rotations may have.

The principal point submitted to the section was the subject of winds, and their relation to the barometer. There appear to be two kinds, -winds of translation and of oscillation. The trades, monsoons, &c., are examples of the former; the latter are winds of local origin, prevalence of rains, &c. It is desirable to make out the law of these movements, and to this end the reduction of the observations is to be continued by Mr. Birt. Already there are marked manifestations of Brussels being a nodal point, and hence hopes of success.

Since the last meeting of the British Association, the committee have obtained and published, in the 11th and 12th numbers of Taylor's Scientific Memoirs, translations of the four following works: Gauss's Dioptric Researches; Dr. Lamont's Account of the Observatory and Instruments at Munich; Gauss's Magnetic Observations at Göttingen; and Lamont's Magnetic Observations (three years) at Munich. No portion of the grant placed at the disposal of the committee has been expended; and this is to be attributed, if we rightly interpret and apply what fell from Sir W. Hamilton, to the acquirements and industry possessed and devoted to the advancement of science by the accomplished lady of the gallant colonel.

Total reflection is a problem in physical optics which has long excited curiosity, and baffled research. Newton's explanation of it affords no account of the phenomena in cases of polarized | light. He considered, however, total reflection to be an insurmountable proof against the undulatory theory of light; and this opinion, very generally adopted, retarded the progress of this science for a century. Poisson was the first to see the mode of solution, by imagining the motion in one direction of two fluids superposed, the one of greater density than the other: the motion would not pass into the rarer medium, and hence the common method of expression was not available, the expression being by sines and cosines multiplied by exponential functions. Fresnel, however, made the greatest advance; he formed certain formulas and expressions, reduced from values verified by experiment, for refracted light. But of refractions beyond the surface he could form no conception; he labored for six years, but he had not the dynamical equations for the motion of light in transparent media. Prof. M'Cullagh found them by conjecture in 1835. He only has recently applied them, and has been able to assign not merely the laws of insensible refraction, but also to explain the nature of total reflection, and to prove each by mutual confirmation. He described the laws of insensible refraction, dependent on the motion of the molecules in rarer medium, being elliptic, not rectilinear, the elliptic vibrations increasing in magnitude as they recede from the glass. In one case only will the vibrations be right lines, and that is when light is polarized vertically. When polarized in the plane of incidence, the vibrations are ellipses, the minor axes being parallel and the major perpendicular

is exactly the same as Fresnel predicted, the laws of total reflection have never before been explained. The explanation, moreover, applies to doubly-refracting crystals, or to the refraction of a crystal in a fluid of a higher refractive power. The laws are extremely beautiful, and completely connect Fresnel's laws of double refraction with the laws of insensible refraction and total reflection.

Dr. Peacocke (chairman pro tem.) proposed the thanks of the section to Prof. M'Cullagh for this exposition of his important researches. He designated the realizing Fresnel's anticipation as the greatest march ever made in physical optics.

The labors of the committee are proceeding. German works which may influence their decision have been ordered. The final report may be expected to be ready for the meeting next year.

The observations conducted by Prof. Lloyd in the magnetic observatory of the University of Dublin extended over a period of four years and a half. The elements observed were, 1, magnetic declination; 2, magnetic inclination; 3, horizontal component; 4, vertical component of the total force. They were not, however, all accurately observed from the first in 1828. There had been a difficulty in obtaining the third element, which difficulty, however, he had overcome. The results of observation were given in a diagram, showing the diurnal changes of declination and inclination for the summer months, for the winter months, and for the whole year. First element; the change of declination is extremely small during the late hours of night and those of early morning-it decreases to 7 A. M. and then rapidly increases, motion westerly, to maximum at 1 P. M.; the succeeding maximum is at 10 P. M. In summer the evening maximum disappears, in winter the reverse takes place; also for the morning maximum, which is well marked in the summer months. The maximum easterly movement is 7 A. M., minimum 1 P. M. It does not reach a maximum in the afternoon, it increases to midnight but slowly, and then faster to morning maximum, and afterwards decreases rapidly. The daily range is greatest in August, being then 13'7; least in January, 7'2. The mean daily range for Dublin is 9.3 minutes. One remarkable fact, however, is, that the period of the minimum at past 1 P. M. is nearly constant during the year. Second element: magnetic inclination has two maxima and minima during the day-a minimum at 3 A. M., maximum 5 A. M.; principal minimum past 10 A. M., principal maximum 6 P. M. In the summer months the morning fluctuation is obliterated. In the winter months the double maxima and minima appear, and also a third maximum, the evening maximum breaking into two. The daily range is greatest in July, 0-0045; least in January, 0.0008; mean, 0-0024. Third element, obtained by balance-magnetometer and by induction, whence are deduced the changes of total intensity and inclination: inclination greatest past 10 A. M., minimum between 5 and 6 P. M., extending in winter to 2', and in summer to double that amount. It corresponds nearly in

period with the intensity, the curves being similar, but inverted. There appears to be a daily change in the total intensity decreasing to 9 A. M., increasing with double maxima and minima in the afternoon; and so remarkable as to lead to the belief that these phenomena depend on the sun. But on farther experiments and comparisons, Prof. Lloyd was led to conjecture that there were other causes than the direct action of the sun, acting indirectly. The change of total force appears to observe law, but it is extremely small in comparison with the changes of declination and inclination. The observations to determine the annual or secular change are not yet numerous enough; but he hoped to complete them before the next meeting of the Asso-ganic matter must have been removed. On these, ciation.

Col. Sabine spoke to the great interest attaching to these observations, and to the prodigious labor given to them in Norway. The observations have been taken there every ten minutes, day and night, and the results are in course of reduction.

Dr. Scoresby communicated the results of his experiments on the circumstances which affect the energy of artificial magnets, their mutual relation, influences, and anomalies. He spoke also of the value of large magnets for locomotion, and of their being so much more useful to this end than electro-magnets. He has constructed a magnet that will support a ton weight.

After mentioning the views entertained by Möser and Draper, and remarking on the very unscientific nomenclature of the latter, the author proceeded to show that the hypothesis of latent light radiating in darkness, was quite uncalled for and unnecessary in explaining these very remarkable phenomena. That the effect is due in some way to the calorific element, the author thinks he has proved by the following experiments. A condensed prismatic spectrum was kept fixed by a good heliastat upon one spot on a plate of copper for three hours. The plate was then submitted to the action of mercurial vapor. The space covered by the visible chromatic spectrum was untouched by the vapor, which had deposited in a thin film over the other parts of the plate; but over the space occupied by the extra-spectral red ray the deposit of va por was much greater than on any other part, forming a well-defined white space. The experiment was varied by allowing a very condensed prismatic spectrum to traverse slowly over a copper plate for two hours. It was found, on exposing the plate to the vapor of mercury, that the space covered by the luminous spectrum was, as before, left free of vapor; but a well-defined line marked the path of the extra-spectral red ray. An arrangement was made by which, by means of colored media, the calorific, luminous, and chemical rays were isolated with tolerable purity. Under each of these, a copper plate, having a design in paper on its surface, was placed, and left exposed to the light of the sun for an hour. On removing the plates in the dark, and exposing them to the vapor of mercury, there was no impression found upon either plate, except the one under the influence of the red rays. This experiment was many times repeated, the results being in each case the same.

The author then mentioned the theory of M. Fizeau, which theory has been followed by some others, who attribute the formation of these images to an organic film of a volatile nature, which he supposes diffuses itself over the surfaces of all bodies. It was contended, that if the impressions were thus formed, they would exist only on the surface of the plates, whereas it had been found that a molecular change was produced to some considerable depth in the plate, that many surfaces might be removed, and still the image rendered apparent. Several experiments were instituted, in which copper plates carefully polished with polishing stones and water, and then boiled, and so dried that any ormedals and coins, all of them carefully washed in boiling water, were placed, and allowed to remain for different periods. While, at the same time, plates and medals, which by rubbing with the hand had been covered with these supposed films, were placed alongside of them. All were examined in the same way, and the effects were nearly the same upon the boiled plates as upon the others. We select two of these experiments in illustration. On a copper plate, which had been kept for some time in boiling water, bronze and silver medals prepared in the same way were placed, the whole being at the temperature of 61.5 Fahr. The temperature was elevated by the spirit-lamp to 89°, and the whole left in contact until the thermometer fell to 62°. Breathing on the plate gave a defined outline of the space occupied by the silver medal, the vapor being deposited on the space covered by the rim. But the vapor of mercury attacked the plate generally, leaving the space corresponding with the rim quite free of vapor. Of the bronze medal there was no impression. It has been repeatedly observed, that when two medals, having in relation to heat different conducting powers, are placed on the same plate, that one interferes with the impressions which the other would have made if placed by itself. On a piece of plate-glass, washed with boiling-water and caustic potash, with a bronze medal, a silver one, a sovereign, and a shilling, placed on its surface, was placed under the receiver of an air-pump, and a good exhaustion kept up for 18 hours; a very distinct image of each of these coins and medals was seen when the plate was vaporized. Thus it appears to be proved that the action is quite independent of any organic film or deposit of dust, which has also been brought forward in explanation of these magical phenomena.

The next paper in the list was No. 8. This supplementary report, the principal points of which only were submitted to the section, presents the results of experiments in a more complete shape than those which Mr. Scott Russell had formerly laid before the Association; the essential difference in the characteristics of the different classes of waves having been ascertained. In water there are four distinct classes of waves; of these the fourth is the common sound-wave, introduced merely to give completeness to the system. The third class had not previously been examined to any considerable extent, if at all. The following is the

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