them more uniformity in density, and greater refractive power. The And now, to trespass on your time only for a few minutes longer, I will conclude this Paper by offering a few remarks on reflecting telescopes. The reflecting instrument was the invention of Father Mersenne, a Frenchman, in the middle of the seventeenth century, by which chromatic aberration was superseded. This was a most important move towards perfection in telescopic observations. main feature of these instruments is, as is tolerably well known, the having a concave mirror, on which the rays of light are received, and from thence are thrown forward to a certain point, and the image thus formed magnified by means of the eye-piece; but the construction has varied in details. Thus Newton's plan was, to have a small plain mirror, inclined at an angle of 45°, near the point where the rays met, to throw them on one side of the tube or body, and there to place the eye-piece. That suggested by Gregory had a small aperture in the centre of the large speculum; opposite to this he placed a second mirror, of an inch or less in diameter, in the axis of the larger one, and thus the image is viewed through the eye-piece of the speculum. In this arrangement, the observer views the image in a line with the tube and the object itself. In that of the Newtonian arrangement, the observer is at the side; and, from this last circumstance, it is extremely convenient when viewing objects in the zenith, or approximately so. Cassegrain's plan was a modification of Newton's. Herschel's plan differed from all these. He inclined the large speculum in order to throw the light to the extreme edge of the upper opening of the tube, so that the observer sat with his back to the object under observation. This was the plan he adopted in the large instrument which he erected at Slough in 1789, which had a diameter of four feet. This E instrument has, in regard to size, been quite eclipsed in our own time by the leviathan instrument of the late Lord. Rosse. This form of instrument offers such advantages to the observer in the way of convenience of posture while observing, that I am not surprised it still finds so many adherents. But all reflectors have a most serious drawback in the way of liability, amounting almost to a certainty, of becoming oxidised; and when one has become so deteriorated, nothing, but going through the whole process of re-working, can restore it to its original efficiency. It is a simple matter to remove the tarnishing by a hand process; but in so treating a speculum, however perfect its original figure may have been, this is certain to ruin it. From these facts, I have formed the opinion that reflecting telescopes should be in the hands only of the amateur workman. As successful workers of metallic specula may be named Ramsden, Short, Reichenbach, and others. Much has been done and said of late about glass-silvered specula. The performances of some of these instruments, worked by Mr. With, of Hereford, have been good; but they oxidise sooner than a good metallic speculum; and though it is true that they can be re-silvered at a nominal cost, yet I have to learn why, in the process of hand polishing, there should be an immunity from spoiling their figures any more than in the metal specula. From these and other circumstances, I have no hesitation in saying, that, in this country at least, where humid atmospheres so prevail, the refracting telescope will ever remain the favourite instrument among the star-gazing fraternity. LANDMARKS IN ENGLISH CONSTITUTIONAL HISTORY. BY J. A. PICTON, F.S.A. SYNOPSIS. The continuity of English institutions-Difference in this respect from Continental history-Capacity for self-government possessed by the Low German races-Traces to be found in Cæsar and Tacitus-The principles involved-Migration to England-Institutions of the AngloSaxons-The effects of the Norman Conquest-Inferences from Domesday Book-Rise of the feudal system-Continuance of the fundamental Saxon institutions-Evils of the feudal system-Influence of the Church-Saxon institutions in the reign of Henry I.-Objects of Henry II.-Abuses of the sacerdotal jurisdiction-1st Landmark: The Constitutions of Clarendon, A. D. 1164-Assize of Clarendon-Assize of the Forest-First taxing of chattels -Commission under Richard I.— Reign of John-2nd Landmark: The Great Charter-The nature of it-Thirteenth century-Fiscal difficulties-Growth of the representative principle-Summons to arm-Provisions of Oxford-3rd Landmark: The issue of Writs to the Boroughs, 1264-Reign of Edward I.— 4th Landmark: The Statute of Mortmain, A.D. 1279-Writs for distraint of knighthood, A. D. 1278-Statute of Westminster-5th Landmark: Statute " Quia Emptores," A.D. 1290-6th Landmark: "De Tallagio non Concedendo," A. D. 1297-Circumstances which led to this-The Petition of Right-The Bill of Rights-The Habeas Corpus Act. THE most remarkable feature about the history of England is the continuity of its institutions. In the words of our poet laureate, language not more poetical than true, our country is hailed as In this respect, England differs from almost every continental nation. To say nothing of France, which in the last century deliberately cut herself adrift from all traditions and associations of the past, it will be found that both Germany and Italy, partly owing to their innumerable subdivisions of territory and changes of dynasty, and partly from the want of sympathy and co-operation between the different orders of society, have lost, to a very large extent, that traditional and historical connection of the present with the past, which is the peculiar glory of England.—I say advisedly of England, for it is to the south of the Tweed that the flame of freedom has been kept alive in the darkest hour; and never in the worst of times allowed to be utterly extinguished. Ireland, unfortunately, has never known or appreciated true freedom at any period of her history; and Scotland, until her union with her southern sister, passed through continual paroxysms of despotism, alternating with turbulence and anarchy.* It is a singular fact that the capacity for self-government seems to belong, in a peculiar degree, to the Low German races, the Saxons, the Angles, the Flemings and Hollanders, and, in a lesser degree, to their Scandinavian kindred. However this may be, it has certainly not developed to anything like the same extent amongst the other races of the earth. Its germ will be found to exist in the earliest accounts we possess, in the pages of Cæsar and Tacitus, of * L'Angleterre est le type le plus parfait de la marche régulière des États sortis de la feodalité du moyen âge, puisque sans rompre avec sa royauté, avec sa noblesse, avec ses comtés, avec ses communes, avec son Eglise, avec ses universités, elle a trouvé moyen d'étre l'État le plus libre, le plus prospère, et le plus patriote qu 'il y ait."-ERNEST RENAN, Reforme Intellectualle et Morale, 1871. This idea of continued and uninterrupted development is one that seems absolately to over-ride our age. It is scarcely possible to open any real and able book on any subject without encountering it in some form. It is stirring all science to its very depths; it is revolutionising all historical literature."--LECKY, History of Rationalism, i. 183. the primitive inhabitants of the German forests. The two great principles on which all true liberty must be based,personal, individual freedom, limited only by necessary restrictions, and mutual responsibility between the governors and the governed,-may be traced through all the devious course of the Anglo-Saxon history; sometimes obscured and hidden under a cloud, sometimes breaking forth into violence and outrage; but at length gaining the ascendancy, and, finally triumphant, gradually pervading all our institutions, moulding the national character, and bringing all our laws into harmony with justice and right. The story is a noble one, and has been often told. In the glowing pages of Macaulay it shines with attractive brilliancy; and in the more philosophical treatises of Hallam and Palgrave we may see realised the truth of the maxim that The I am not about to repeat the tale; my task is a much |