soon as they return hither. But I assure you, on the word of a king, I never did intend any force, but shall proceed against them in a legal and fair way, for I never meant any other. And now, since I see I cannot do what I came for, I think this no unfit occasion to repeat what I have said formerly, that whatsoever I have done in favour, and to the good of my subjects, I do mean to maintain it. I will trouble you no more, but tell you I do expect, as soon as they come to the house, you will send them to me; otherwise I must take my own course to find them.' With these words the disappointed king rose and retired, amidst loud cries of 'Privilege! privilege!' and the house instantly adjourned. That night the city was a gayer place than the court. Early on the following morning the commons, safe in 'that mighty heart,' sent Mr. Fiennes with a message to the lords, to give them notice of the king's coming yesterday,' and to repeat their desires that their lordships would join with them in a petition for a guard to secure them, and also to let them know that they were sitting at Guildhall, and had appointed the committee for the pressing Irish affairs to meet there. The commons then appointed that a permanent committee should sit at Guildhall, in the city of London, with power to consider and resolve of all things that might concern the good and safety of the city; and thereupon adjourned till Tuesday, January 11th, at one in the afternoon. In the meantime, Charles had sent orders to stop the seaports, as if the five members could be scared into a flight. On the morning, after a night of painful doubt and debate, Charles set off to the city in person, with his usual attendants, but without any reformados or bravos. On his way he was saluted with cries of Privileges of parliament !' 'Privileges of parliament!' and one Henry Walker, an ironmonger and pamphlet writer, threw into his majesty's coach a paper whereon was written, To your tents, O Israel.' The common council had assembled at Guildhall, and they met the king as he went up to that building almost alone. Concealing his ill-humour, and his irritation against the citizens, he thus addressed them:-'Gentlemen, I am come to demand such persons as I have already accused of high treason, and do believe are shrouded in the city. I hope no good man will keep them from me; their offences are treasons and misdemeanours of a high nature. I desire your loving assistance herein, that they may be brought to a legal trial. And whereas there are divers suspicions raised that I am a favourer of the Popish religion, I do profess in the name of a king, that I did, and ever will, and that to the utmost of my power, be a prosecutor of all such as shall any aways oppose the laws and statutes of this kingdom, either Papists or Separatists, and not only so, but I will maintain and defend that true Protestant religion which my father did profess, and I will continue it during my life.' This conciliatory speech produced little or no offect; Charles did not get the five members, but he got a very good dinner at the house of one of the sheriffs, and after dinner returned to Whitehall without interruption or tumult. TRUE DISCOUNT. (1) What is the true discount on £320 due in 4 months at 6 per cent. per annum ? (2) What is the present value of £370 due 100 days hence at 41 per cent. true discount? (3) What is the true discount on £627 due in 120 days at 10 per cent. per annum ? (4) A bill of £78 10s. will become due on the 1st of September; what ready money will pay it on the preceding 3rd of July, allowing 6 per cent. per annum true discount? (5) What is the present value of a £762 bill payable on October 13th, if I discount it on August 1st at 8 per cent.? (6) Should I gain or lose by using true instead of ordinary discount in the above case, and how much? SCIENCE AND POETRY. (From the Museum of Science and Art,' by Dr. Lardner.) noc-tur'-nal, nightly cli-mat-o-lo'-gi-cal, relating to the laws of climate ul'-tra trop'-i-cal, beyond the tropics in-com-pat-i-bil'-i-ty, inconsistency vis'-u-al, relating to the sight hy-per-crit'-i-cal, critical beyond reason as-tro-nom'-i-cal, relating to the science of astronomy lo'-cus stan-di (Lat.), a standing place or-i-fice, an opening pos-te'-ri-or, later, back pho-to-met-ric, relating to the measurement of light In one of his Irish melodies, so familiar to all lovers of poetry and music, Moore has the following lines : Oh! had we some bright little isle of our own, In a blue summer ocean far off and alone, Where a leaf never dies in the still, blooming bowers, And the bee banquets on through a whole year of flowers; With so fond a delay, A thin veil o'er the day; Where simply to feel that we breathe, that we live, Now this is good poetry, but bad science. An 'isle' in which ' a leaf never dies,' and in which the flowers bloom through the year, must necessarily be within the tropics, a latitude to which the succeeding lines about the 'fond delay' of the sun and the night, which only draws a thin veil o'er the day,' which pro duces, in other words, only a few hours of twilight, are utterly inapplicable. In tropical latitudes the variation of the length of the day is very inconsiderable. It is a little more or less than twelve hours, and that is all. The night is, consequently, subject to a variation similarly limited. Instead, therefore, of the very long day and the very short nights which the poet ascribes to his 'isle' in the blue summer ocean, there would necessarily be nights, the duration of which could never be much less than twelve hours in any part of the year. But this is not all. Instead of enjoying a constant nocturnal twilight, so beautifully described by the poet as a veil drawn over the day, the inhabitants of the tropics enjoy scarcely any twilight at all, being plunged in nocturnal darkness almost immediately after sunset. This arises from astronomical causes, which will be very easily understood. Twilight is produced by the reflection of the sun's light from that part of the visible atmosphere upon which the sun continues to shine after sunset until its depression below the horizon amounts to about 18°. Now it is apparent, that the more nearly perpendicular to the horizon the diurnal motion of the sun is, the sooner will its orb attain this depression of 18°. In the higher latitudes, where the celestial pole is not very far removed from the zenith, the sun is carried round in a diurnal circle, making a very oblique angle with the horizon; consequently, after it sets, its depression below the horizon increases very slowly, and a long interval elapses before the depression amounts to 18°. In some latitudes, at the season of Midsummer, it is not so much as 18° even at midnight; and in such places the poet might very truly say, The night only draws A thin veil o'er the day. But the latitudes in which this can take place are very different indeed from those in which A leaf never dies in the still blooming bowers, And the bee banquets on through a whole year of flowers. The distance of the celestial pole from the northern point of the horizon being always equal to the latitude of the place, the depression of the sun below the horizon at midnight will be found by subtracting the latitude of the place from the sun's polar distance. Now, the sun's polar distance at Midsummer is 664°, and in order that its depression at midnight should not exceed 18°, the latitude of the place must at least be equal to 66°, diminished by 18°, that is 481°. It follows, therefore, that an entire night of twilight can only take place at latitudes higher than 48°. But to produce the effect expressed by the poet, a twilight should be maintained much stronger than that characterised by the scientific sense of the term. A twilight which would be only a 'thin veil drawn over the day,' would be such as can be only witnessed in latitudes like those of Norway and Sweden, the northern parts of Scotland, the Orkneys, &c. In tropical latitudes, on the contrary, the celestial pole has an altitude less than 231°, and the diurnal path of the sun makes with the plane of the horizon an angle greater than 66°. After sunset, the sun therefore descends very rapidly, and the more rapidly the nearer the place is to the line. At the line itself the sun attains the depression of 18° in about seventytwo minutes after sunset; and although the twilight in the scientific sense of the term would not terminate till then, it comes to a close much sooner in the poetic sense of the 'veil drawn o'er the day.' In short, an almost sudden darkness succeeds sunset, and, in like manner, sunrise succeeds as suddenly to the darkness of night. In a word, the poet, in the beautiful lines cited above, has combined incompatible astronomical and climatological conditions. The perpetual summer necessarily infers tropical latitude, while the short twilighted night infers a high, not to say a polar latitude. It would, perhaps, be deemed hypercritical to examine how far the naturalist would justify the poet in his allusion to the industry of the bee in a tropical climate. The honey-bee, which no doubt was the insect alluded to by the poet, is, for the most part, confined to ultra tropical latitudes. Since, however, there are certain species of this insect found in the lower latitudes, it may be admitted that the poet has, at least in this point, a locus standi. Having had the pleasure of the personal acquaintance of the author of the Melodies, I once pointed out to him these scientific incompatibilities in his lines. He replied good-humouredly, that it was lucky when he wrote the song that such inconsistencies did not occur to him; for, if they had, some pretty thoughts would inevitably have been spoiled, since he could not have been brought knowingly to take such liberties with the divinities of astronomy and geography. The allusion and imagery which Moore loved to seek in certain parts of physical science were generally much more consistent with physical truth, without being less beautiful, than that which we quoted above. How happily, for example, did he avail himself of that beautiful property of the iris by which it accommodates the eye to greater and less degrees of light, enlarging the pupil when the light is faint, and contracting it when it is intense. The iris, as is well known, is the coloured ring which surrounds the dark spot in the middle of the eye; this dark spot being not a black substance, but a circular orifice through which the light is admitted to the membrane lining the posterior part of the internal chamber of the eye. This circular orifice is called the pupil, the retina being the nervous membrane which produces the visual perceptions. The iris which surrounds the pupil has a certain power of contraction and expansion, which is produced by the action upon it of proper muscles provided for that purpose. The quantity of light admitted through the pupil to the retina is increased or diminished in the proportion of the area of the pupil, which increases and diminishes in proportion to the square of its diameter; a very small variation of which therefore produces a very considerable proportionate variation of the quantity of light admitted. If a person, after remaining for some time in a room dimly lighted, pass suddenly into one which is strongly illuminated, he will become instantly sensible of pain in the retina, and will involuntarily close his eyes. After a short time, however, he will be enabled to open them and look around with impunity. The cause of this is easily explained. In the dimly lighted room the pupil was widely expanded, to collect the largest quantity possible of the faint light, so that a sufficient quantity might be received by the retina to produce a sensible perception of the surrounding objects. On passing into the strongly illuminated room the expanded pupil admits so much of the intense light as to act painfully on the retina before there is time for the iris to adjust itself so as to contract the aperture of the pupil. After a short interval, however, this adjustment is made, and the area of the pupil being diminished in the same proportion as the intensity of the light to which it is exposed has been augmented in passing from one room to the other, the action upon the retina is proportionally mitigated, so that the eye can regard without pain the surrounding objects. The reverse of all this takes place when the eye suddenly passes from strong to feeble illumination. The pupil contracted when exposed to the strong light is not sufficiently open to admit the rays of feeble light necessary to produce visual perception, and for some time the surrounding objects are invisible. When, however, the proper muscular apparatus has had time to act upon the air so as to enlarge the pupil, the rays are admitted in greater quantity, and the surrounding objects begin to be perceived. These phenomena are beautifully expressed by the lines of Moore: Thus when the lamp that lighted The traveller, at first goes out, |