appear in parallel planes, the furthest image appearing through the first apparent surface. Small pictures have a singular effect applied in this manner.

When other sounds co-exist with the fundamental, the images are multiplied, but they become fainter as their number increases: these multiplied images are equally visible, whether the vibrations be rectilineal, elliptical, or circular.

A New Optical Experiment.

As that property of vision which occasions the apparent duration in the same places of visible images, after the objects which excite them have changed their positions,* has enabled us to submit to inspection the phenomena above described, it may not be irrelevant to subjoin a description of an apparatus which illustrates the transient duration of the impressions of light in a very evident manner.

At the back of a wooden frame, about six inches in height and breadth, and from one to three inches or more in depth, a circular plate of glass is placed, upon which a design is painted with transparent colours; at the front, is placed, parallel to the glass, a circle of tin, covered on its exterior surface with white paper, and having the space between two adjacent radii cut out. This circle moves freely on its centre round an axis, supported by a bar in front, and is put into rapid and regular motion by the application of any mechanical principle proper for the purpose; and a catch is so placed, that when the motion ceases, the aperture shall be concealed by the bar which supports the axis,

If a light be placed behind the transparent painting, and still better if it be concentrated by a lens, on making the circle revolve with rapidity, the whole of the picture will be rendered visible at one view, although but very limited portions are successively presented to the eye.

The intensity will differ in proportion to the excess of the transmitted light above that which falls in front of the circle; it will, therefore, increase the distinctness of the picture, to darken the latter as much as possible.

*It has been proved by the Chevalier d'Arcy, from the only experiments approaching to accuracy which have been made on this subject, that the extent of this duration is eight thirds. See his "Memoire sur la durée de la sensation de la vue:" Hist. de l'Acad. An. 1765.

352

London in 1826, with respect to its present State of Architectural Advancement. Read before the Literary and Philosophical Society of Liverpool: Sessions 1826,

HAVING lately had opportunities of examining the external aspect of the British Metropolis with much attention and in great detail, and having compared it with such of the other European capitals as I have seen, and with the rest, from a careful inspection of plans, descriptions and drawings, it has occurred to me that a few observations on the subject would not be altogether undeserving the attention of this society.

I find it generally admitted that, with respect to architectural improvement, London has made greater advances since the late peace, than in the entire century which preceded that most auspicious event. Public spirit has been more directed into this channel; the remission of war has enabled the nation to devote more expense to such objects; and above all, a taste for architectural embellishment, both in public buildings and private dwellings, has accompanied the natural progress of arts and knowledge in this refined community. If the career which has so lately been entered upon should happily not be interrupted by the recurrence of war, a still greater improvement in this most striking and resplendent of all the arts may be confidently anticipated.

As the architectural pretensions of London are therefore, in a very great degree, of a recent date, the subject is not destitute of novelty; no writer, as far as my knowledge extends, having as yet published any notices of the British capital in its present state. The inquiry must be admitted to be interesting, since the vast city, in its actual condition, presents a spectacle to which the history of ancient and modern civilization, in all probability, affords no parallel. Within the limits of this civilization, there is reason to believe so large a mass of human beings have never before been congregated on so small a space of ground. As to the great cities of antiquity, our information concerning their size and population is too vague, as well as too scanty, to enable us to speak with any precision If we are to believe the exaggerations of Herodotus and other

ancient writers, the cities of Nineveh and Babylon were of a magnitude to which nothing in subsequent ages will bear a comparison; but even if their extent be admitted as described, the manner in which they were built and inhabited would still afford grounds for believing that their population did not equal that of London. The pretensions of ancient Rome are somewhat more plausible. The development, however, of the ruins of Herculaneum and Pompeii have afforded us an insight into the comparative density of the inhabitants in ancient and modern towns, which tends much to abate our estimate of the eternal city; so that, rejecting the extravagant notions of Vossius, Lipsius, and other modern writers, we may, after a careful comparison of circumstances, suppose with Hume, that the population of ancient Rome may have reached somewhere about a million. The other great cities of ancient times, such as Ephesus, Agrigentum, Syracuse, Antioch, Alexandria, &c., need not be mentioned, since no calculation that I have seen raises their population to a million. With respect to modern ages, it has been thought by some writers that two or three cities of China and Japan exceed the limits of the British capital in size and population; but in the first place, no accurate census of these cities has ever been taken, and in the second, it is believed that a considerable portion of their inhabitants consists of hordes of Tartars or other migratory tribes; so that these places may safely be put out of the question in any inquiry which respects the cities of the civilized world. Our information concerning their detail is besides too imperfect to be made the basis of any observations.

This digression concerning the unexampled magnitude of our metropolis is not wholly impertinent in estimating its physical properties as a city. Many of its peculiarities, and some of its principal defects, arise necessarily from its enormous

extent.

London owes its pre-eminent size to a conjunction of circumstances which have never concurred, in any other instance, to the formation of a great capital:-1. It is the greatest seaport in the world; 2. It is the greatest manufacturing city ever known; 3. It is the seat of the most opulent government that ever existed. The first of these assertions admits of no

dispute. The second seems somewhat more doubtful, because many other places appear to exhibit a greater mass of manufacturing industry; but in this point we are deceived by the vast extent of the metropolis, and the consequent diffusion of its scattered manufacturers. According to a late statement of Mr. Huskisson, the silk manufacture alone now reaches the enormous amount of fourteen millions sterling per annum, and is consequently, after cotton, the greatest staple of the country. Of this immense fabric, London is the principal seat, and it nearly engrosses many others of a smaller extent, but yet forming an immense aggregate when taken collectively, such as jewellery, plate, porter, books, newspapers, and many others.

Being, then, unquestionably the richest, largest, and most populous city of Europe; the seat of a wealthier court, and a more opulent body of nobility and gentry, than any other metropolis; it seems only a natural and reasonable expectation that it should likewise excel all others in the number and magnificence of its public edifices and private dwellings; in its general elegancies and accommodations as a city, and in all the appendages and decorations which naturally accompany so manifest a superiority. But this is very far from being the case, and our striking deficiencies in these points afford matter for one of the severest of our national reproaches. An overgrown capital is essentially a great evil, as it is the natural confluence of the worst species of misery, corruption, and crime. It brings together the greatest extremes of luxury and poverty, of rudeness and refinement. The natural, though insufficient compensation for these excesses, is sought for in the splendour of its decorations, and the superiority to which the ornamental arts of life may there be expected to attain. The art of architecture especially, the only one of the arts which requires great wealth for its successful prosecution, may there be expected to rear its head in proud pre-eminence; but the enlightened traveller, who comes to London with this very justifiable prepossession, will find himself miserably disappointed. Till within the last few years, that most splendid and impressive of all the arts has been almost wholly neglected, and the extension and improvement of the capital was left in the hands of sordid ignorance and barbarous caprice.

So much for the general view of the subject: 'I shall now beg leave to descend to a few more minute particulars.

The great architectural superiority of London, such as it is, consists in the number, size, and general neatness of its principal streets and squares. No other city can boast so great a number of streets, equal to those of London in length and breadth, and so uniformly well built. Petersburgh, Berlin, Naples, Turin, Genoa, Antwerp, Edinburgh, and other places, have perhaps finer streets than any in London, but in respect to their number there is no comparison. At present, also, it may be affirmed, that since the completion of the line of street extending from Carlton-house to the Regent's-park, it would not be easy to find in any other city, even a single street which greatly exceeds that magnificent range of buildings.

- Remarks of a similar kind may be applied to the squares. If we assent to the critical canons established on this point, that architectural beauty is constituted by variety amidst uniformity, and that in every regular figure the subordinate parts should bear a certain proportion to each other, it will be found that every square in London is manifestly imperfect. There is none that can be compared with the great square of St. Petersburgh, the Place Vendome at Paris, the Place Royale at Brussels, the Place of St. Marc at Venice, or even with the principal squares in Edinburgh. Yet, when we consider their number, their spaciousness, their enclosures, and their general neatness, they form altogether such an assemblage as no other city can rival. The new squares, such as Bryanstone, Torrington, Bedford, Russell, &c., are tolerably uniform, but they want variety and architectural decoration in their constituent parts. The old, such as Grosvenor, Portman, St. James's, &c., have sufficient variety in parts; but having neither uniformity nor proportion in their whole, nor much beauty in their details, their pretensions are still less. Fitzroy, Tavistock, Belgrave, and Regentsquares, if completed on their respective plans, as far as they are at present developed, will comprise most of the requisites of a handsome square, though not without considerable faults.

If we descend from these general features, to the individual mansions which form this stately assemblage of streets and squares, we shall find them, for the most part, utterly beneath