three-quarters of an inch thick. When these were placed edge to edge, they enclosed a lens-shaped cavity, four feet in diameter, and six and a half inches thick in the middle. This cavity was filled with 140 pints of spirit of wine; and a lens was thus produced which would melt a farthing in half a minute. The focus was, however, very large, and, in order to concentrate it, the rays were received upon a second lens, by which they were brought to such a narrow focus, that pieces of forged iron were fused in fifteen seconds, and hardened steel melted in five minutes. Its effect on platina was curious; some grains of this metal appeared to be drawn together, diminished in bulk, and prepared for fusion; a little afterwards, it bubbled up and smoked; all the grains were united into one mass, but without forming a spherical button, like other melted metals. so much has been done of late years, in the production of an intense heat by chemical means, especially by the oxy-hydrogen blowpipe; that it is not very probable that burning glasses, acting by solar rays, will occupy so much attention hereafter, as they have hitherto. The relation between a burning lens and the oxy-hydrogen blowpipe, is somewhat analogous to that between a sun-dial and a chronometer: the lens and the sun-dial can only be used while the sun is shining: the blowpipe and the chronometer are available in spite of weather, or of temperature, or of the darkness of night. THE SMOKE-JACK. "I give you joy of the report A WORK of considerable learning and extent might by a master's voice. The most powerful burning apparatus ever made was constructed by Mr. Parker, a London optician, about the beginning of the present century. It consisted of two convex glass lenses, connected together by the apparatus represented in our cut. There is a conical-shaped frame-work, at the upper and broad end of which is fixed the larger of the two lenses, and at the lower end the smaller lens. The large lens was double convex; when fixed in the frame it ex-monly as the cook; but now the smoke-jack performs, posed a surface of thirty-two and a half inches; it in a far more effectual and less expensive manner, was three and a quarter inches thick in the middle; the office which a little boy or a poor little dog once focal distance, six feet eight inches; diameter of focus, held. Indeed, one of the strongest incentives to the one inch; and weight of the lens, 212 pounds. The adoption of automatic machinery is the superiority smaller lens exposed a clear surface of thirteen inches and regularity of the work performed by it, compared diameter when in the frame; it was about one and a with the productions of human or animal machines, half inches thick in the middle; focal distance, twenty-that have a will of their own, not always controllable nine inches; diameter of focus three-eighths of an inch; and weight of the lens twenty-one pounds. It appears that boys were employed to turn the The combined focal length of the two lenses was five spit, both before and after dogs were trained to that feet three inches; and the diameter of the focus, half office. Du Cange speaks of a boy-turnspit so early an inch. The conical frame-work was intended as 1201. We also meet with an anecdote of Louis merely to keep the lenses in their proper relative the Eleventh, (about 1460) to the following effect. positions. A rack and pinion was placed beneath the A whim of the monarch led him to visit the royal machine, so that it could be elevated or depressed, kitchen, to see what was going forward. He found a according to the altitude of the sun. A little platform little boy turning the spit. The boy was handsome, or stage was fixed behind the smaller lens, and the and his appearance so engaging, that the king thought stage was capable of being so adjusted, that any sub-him deserving of some better office than the one he stance placed on it would be precisely in the focus of the instrument. With this apparatus experiments were made before the Royal Society. Gold, platina, nickel, and cast-iron, were fused in three seconds; a cube of steel, weighing ten grains, melted in twelve seconds; minerals, gems, lavas, and bodies of similar refractory natures, were fused in times varying from sixteen to eighty seconds. A diamond of ten grains, when exposed to the lens for thirty minutes, was reduced, by evaporation, to six grains. Ten cut garnets were taken from a bracelet, and exposed to the lens; in a few seconds, they all fused together into a globular form. It is remarkable, as showing how little we yet know of the connexion between light and heat, that although the lunar rays are so beautifully clear and bright, not the slightest effect could be produced on a very delicate thermometer, when the lunar rays were concentrated on it by Parker's lens. A similar experiment was tried on the lunar rays, by Buffon and Tschirnhausen, but with a similar want of success; though millions of lunar rays were congregated in one spot, no sensible heat could be perceived. Sir David Brewster, thirty years ago, proposed many improvements in the constructing of burning apparatus, chiefly by combining transmission and reflexion to produce joint effects; and there is no doubt that, in an optical point of view, these suggestions were worthy of the distinguished author, But filled. Louis accosted him, inquired whence he came, who he was, and what he earned by his employment. The turnspit, not knowing the king, replied to his queries, without the least embarrassment, "I am from Berny, my name is Stephen, and I earn as much as the king." "What then does the king earn?" asked Louis. "His expenses," replied Stephen, "and I mine." The king, pleased with the smartness of the reply, promoted the turnspit to the situation of groom of the chamber. The employment of dogs as turnspits has given a distinctive name to a peculiar class of those animals. The turnspit is described as a spirited, active, and industrious kind of dog, once considered as an indispensable attendant on the spit, which, by a peculiar contrivance, and the aid of its own exertions, it was enabled to turn at an even pace. The body of this animal is long, the legs very short, and the tail curled on the back; its usual colour is grayish, with black spots. Gmelin notices three varieties of this family of dogs; one of which has straight feet, another curved feet, and the third has the body covered with long curly hair. The terrier is the Gmelinian Canis vertagus. The method of teaching these dogs their duty was summary rather than humane. The dog was put into a hollow wheel, or drum, and a few live coals with him; thus situated, the poor animal could not pause without burning his legs; he therefore kept up a constant gallop within this canine treadmill. It will be readily supposed that these dogs were not much attached to their profession; for, setting aside the unpleasant associations connected with their apprenticeship, it was hard work to run in a wheel for two or three hours, turning a piece of meat double or treble their own weight. -- Many droll occurrences are connected with canine turnspits; we select one which took place at Bath many years ago. It is related that a party of wags hired the chairmen, on one particular night, to carry off all the turnspits in the town, and lock them up till the following evening. This was done; and next day multitudes of cooks were to be seen in the streets;"Pray have you seen my Toby?" says one. Why," replies the other, "I was coming to ask you if you had seen our Chloe;" when up comes a third inquiring for "her Pompey." There was no roast meat in Bath that day; but there was a good deal of perplexity on the one hand, and amusement on the other. It will be seen from this anecdote, that the turnspits were under the especial protection of the cooks. The introduction of the smoke-jack has happily superseded the use of dogs; and modern cooks have transferred their affection to the cat, which, compared with its canine predecessor, does, indeed, enjoy a sinecure. The principle upon which the smoke-jack acts may be shown by an easy experiment. Upon a flat disk of thin pasteboard describe the spiral, as in fig. 1; let this be cut out, and extended, by raising the centre above the first revolution. Make a small indentation in the centre of the spiral, and then poise it on the point of a wire, as in fig. 2. If the apparatus be placed on a warm stove, or the flame of a lamp or candle be applied below it, the spiral will turn round, apparently without any cause, and continue to spin with considerable velocity. The cause, however, is the air, which, being rarefied by the presence of a heated body, ascends, and thus produces a current which propels the spiral. screw works into a wheel on the axis of the pulley that turns the spit, and the latter is thus carried slowly round. The vanes should be placed in the narrow part of the chimney, where the motion of the smoke and heated air is swiftest: the vanes should also occupy nearly the whole horizontal space of the chimney, so that the greater part of the current may be intercepted. Another form of kitchen-jack is shown in fig. 4, in which the descent of a heavy weight is the moving power. In this machine a line, or chain, of considerable length, is coiled round a central barrel: the other end of this line is passed over pulleys, which are usually situated outside the house, so as to allow a greater range for the weight. A pulley is attached to the spindle of the central barrel, and another is attached to the spit, and both pulleys are connected by means of an endless chain. The suspended weight, in descending very slowly, uncoils the line by turning the barrel round, and thus the spit is made to revolve. To ensure an equable motion, and to get rid of those jerks and irregular revolutions which arise from the unequal spitting of the meat, a toothed wheel is placed on the axis of the barrel: the teeth work in a double-threaded screw, placed upon the spindle of a horizontal fly-wheel, which, rotating with considerable velocity, prevents any irregularity in the motion of the barrel. The weight is wound up by means of a key, which fits on to the projecting square end of the spindle of the barrel. 1 Upon this principle is the mechanism of the smokejack constructed, as represented in fig. 3. A number of vanes of thin sheet-iron are arranged in a circle, but they are all set obliquely. When a fire is lighted below, the air of the chimney becomes rarefied, ascends, and creates a partial vacuum: fresh air pours in, and, by the construction of the fire-place, the greater part of it must pass through the burning fuel. This gives to the "draught" of air in the chimney a considerable ascensive force, which force is greater in proportion as the chimney is tall; the ascending air, therefore, striking upon the surfaces of the inclined vanes, causes the spindle, to which they are attached, to rotate, and this motion is communicated to the spit by means of a small bevelled wheel, which works into another small wheel, placed upon a horizontal axis, with a screw cut upon the other end of it; this THE tree of knowledge is grafted upon the tree of life; and that fruit which brought the fear of death into the world, budding on an immortal stock, becomes the fruit of the promise of immortality.--SIR HUMPHREY DAVY. THE affections imply a spirit of self-sacrifice, and often our virtues, like our children, are endeared to us by what we suffer for them.-SHARPE. J THE wheat, although it lies awhile in earth, Where we in immortality shall shine.-WITHER. GENUINE praise, like all other species of truth, is known by its bearing full investigation; it is what the giver is happy that he can justly bestow, and the receiver conscious that he may boldly accept; but adulation must ever be afraid of inquiry, and must to their degrees of moral sensibility Be shame to him, that gives and him that takes. 6. SARACENIC ARCHITECTURE. WHEN Constantine, in A.D. 328, founded the city of Constantinople, he enriched it with the treasures of Rome: all that could be removed was taken from the "imperial city," to adorn his new capital. At a subsequent period, when the successor of Constantine removed from the city every valuable specimen of art, (which Alaric had spared in the sacking of Rome,) he loaded several ships therewith, which were driven by a tempest upon the coast of Sicily; the commander was killed, and the Saracens, then in possession of the country, carried their spoils to Alexandria. The Arabian, Saracenic, or Moorish architecture is another illustration of the remark already made of the influence of religion upon architecture. The religion of Mohammed was diffused from Indus to the Nile, by Arabs, whose fanatical zeal led them to put to the sword all who refused to own the doctrines of the Koran. The Roman power had declined, and the eastern countries, once subject to it, were so enfeebled by luxury or misrule, as to fall easily under the dominion of the arch impostor and his immediate successors. In a very few years Syria, Persia, and Egypt were VOL. XVI. totally subdued; more than four thousand Christian churches were destroyed, and rude shrines, called maschiads, afterwards mosques, were substituted. But as the religion of Mohammed became more securely settled, its followers acquired a love of luxury and splendour, accompanied by a taste for learning and the arts of life. The literature of the Greeks was translated into Arabic, and schools were established for the study of science, especially mathematics, in which the Arabians greatly excelled. Thus, while Europe was involved in darkness,-while the rude tribes of the north subjected the fairer portion of the Roman empire to devastation and ruin,-the Arabians were advancing in civilization, and obtaining that efficiency in the arts of peace and war, which made them so long celebrated. The earlier style of the Saracenic architecture bears some resemblance to that which prevailed in the Byzantine empire. It is probable that the cupolas of their earlier buildings were suggested by those of Sancta Sophia, and similar structures; and the columns which they, employed, if not actually taken from existing Roman structures, were rude imitations of them. But as they advanced in science and 513 art, they seem to have constructed temples peculiar to themselves; and, disdaining any longer to borrow the idea of them from the nations they had conquered, they invented, or rather composed, from the study of Egyptian, Greek, and Roman édifices, that style which, even to the present day, is to be seen wherever Mohammedan dominion prevails. Saracenic architecture is singularly light and fantastic, yet marked with grace and elegance. It is exceedingly difficult to define, on account of that endless variety of form which everywhere prevails. Their columns are slender and variously formed, and are employed generally to support low arcades: the shafts are short and thin; plain, or ornamented with lines in perpendicular or spiral grooves: the capitals are either imitations of the Grecian orders, or formed of foliage variously disposed, and crowned with a plain abacus. In Saracenic architecture we always find large numbers of these columns, either clustered or in rows. The Arabians are also celebrated for their arches of which three sorts were employed; viz., the crescent, or horse-shoe arch, the round arch, and the cuspid arch. The first form of arch is peculiar to Mohammedan architecture. The crescent is the symbol of the Mohammedan faith, as the cross is of the Christian; and its form is said to have been first introduced in architecture by Muavia in his new capital of Damascus. It was called the sacred arch, and was splendidly adorned with sculpture: it formed the usual entrance of mosques. This arch may be considered as the really distinctive feature of the Saracenic style. The round arch was simply an imitation of that of the Romans, and seems to have been used indiscriminately by The cuspid arch was formed by segments of circles, meeting in a point at the vertex. the Arabians. 7. THE SECOND CHRISTIAN ERA. They dreamt not of a perishable home WORDSWORTH. DURING the middle ages, when intercourse between distant nations, and even between neighbouring states, was unthe arts of civilized life were almost in a torpid state; when certain and difficult; when the pursuits of commerce and improvements were slowly introduced, and carelessly received, it is especially worthy of remark that architecture became more widely diffused, at the same time that it presented a greater uniformity of feature, than has been the case in any succeeding, and apparently more favourable to each other in all the buildings of that date, however distant the countries in which they were constructed, but there was also a rapid adoption of new forms and combinations: so that, whenever a variation of style occurred in any particular spot, the knowledge and imitation of it were speedily found to prevail in places the most remote; and even such buildings as had been commenced according to some other style were altered and fashioned in accordance with the As the religion of Mohammed forbade the representation of animals, the ornaments of the Arabians consisted of coloured glazed tiles and mosaics, which were employed in a fanciful yet tasteful manner, in adorning their apart-period. And not only did there exist a striking resemblance ments: other ornaments were made to consist of texts of the Koran, inlaid in the form of mosaics, and often adorned with precious stones; of plants, stalks, and foliage gracefully entwined, either painted or formed in highly relieved stucco. The enrichments of Moorish edifices are very much confined to flat surfaces, the walls being sculptured all over with ornaments. The appearance of the buildings erected by Mohammedan conquerors in Spain leads to the supposition that the idea of thus ornamenting them must have been derived from the hieroglyphical embellishments of Egyptian temples. From the general appearance of these Moorish ornaments has arisen the term Arabesque or Moresque, applicable to all ornaments of a fantastic cha racter. Another species of ornament, called fret-work, is also prevalent in Arabian architecture. It is said to have originated with the Persians, as a sort of screen capable of admitting air and light, and excluding the direct rays of the sun. This form of ornament admitted of a great display of elegant taste. Corbelling has also been referred to the same style: but its origin is very doubtful. Corbels are projections from a wall, intended for the support of any object. The Arabians used them most in their castles, to support a projecting parapet, in the floor of which were perpendicular holes, called machicolationst, whence the besieged could, under cover, dart missiles, and pour down melted pitch, and other destructive materials, on the besiegers who should attempt to scale the walls. new mode. To account for this remarkable fact, we may observe that, at the period of which we are speaking, when the lay por tion of the community was engaged in constant warfare and devastation, the only safe places of retreat where industry might be employed, and the arts might be exercised, were the churches and convents. The study of architecture was chiefly confined to the members of religious communities; and at that time also, the skill and taste of the architect had scarcely any other object than the erection and ornament of sacred edifices: hence we may trace, in the intercourse maintained between the different monasteries, and in the frequent journeys performed by monks, on the concerns of their various orders, the means by which a knowledge of architecture, and of the variations introduced therein from time to time, might be transmitted from one country to another, and acted upon in the manner before mentioned. But another, and more universally prevailing cause for the similarity of architectural buildings at that period, seems states of Italy to trade, commerce, and independence, and to be the awakening of Lombardy and the neighbouring the formation among their citizens of companies, free corporations, or guilds, possessed of the exclusive privilege of exercising their peculiar trades or professions. Not only mere mechanical employments, but those of a more intellectual nature, were submitted to the shackles and We see the Arabian style well displayed in the numerous mosques, tombs, and mausoleums of the Mohammedan religion; the most prominent features of which are the towering domes and encircling minarets. The latter are light, circular turrets, rising high above the other parts of the building, and furnished at the upper parts with project-restrictions of these guilds, and were only to be entered on ing galleries, where the muezzins call to prayers. The figure at p. 253 represents this act, as also some of the broader features of Arabian architecture. We may also refer to the description of the Moorish palace of Alhambra, (Saturday Magazine, Vol. I., p. 114,) as affording some idea of the splendour of Saracenic architecture. About the tenth century, however, the caliphs introduced sculptured animals, such as lions, griffins, &c., supporting columns, and adorning fountains. This word, resulting from the union of a Latin and a Greek word, implies war-sieves. by a hard and severe apprenticeship. kings and queens were emulous of filling their dominions When Lombardy had embraced the Christian faith, its full activity the talents and resources of the company of with churches and monasteries: thus were called into builders, who had associated themselves into similar bodies to those just described, and who, after passing the different fixed stages of apprenticeship, were received as masters, and entitled to exercise their professions as "free and employment for these companies, or make their privileges of accepted masons." But Lombardy itself could not long find great and important benefit to them: another sphere was accordingly sought by them, and in the north of Europe, where the gradual spread of Christianity produced a corresponding need for sacred edifices, they found that occupa tion which had begun to fail them in their native land. Endowed by the Pope with peculiar rights and privileges, the masonic associations went from city to city, and from country to country, regulating for themselves the price of their labour, prohibiting native artists from entering into competition with them, and claiming entire exemption from the laws and statutes of the countries in which their services were required. Whether they entered a country of their own accord to seek employment there, or whether they were called thither by missionaries who had preceded and prepared the way for them, they were always headed by a chief surveyor, who governed the whole party, and appointed one man out of every ten, under the name of "warden" to overlook the nine others in their work. Thus did the architects of all the sacred edifices derive their knowledge from the same source, and obey the rules of the same central school; and thus is explained the otherwise inexplicable fact of the similarity of construction in buildings the most remote from each other, and which are known to have been erected almost simultaneously; hence also the rapidity with which changes in the style of architecture were adopted in different countries more or less distant from each other. So numerous at length were the masonic companies, that many were frequently seeking to erect religious edifices in the same country; while so emulous were they of distinction in their art; so devoted in the employment of their faculties on that single study, that, difficult and complicated as their subject was, they were enabled to attain an eminence, and to advance the art to a degree of perfection, which would be to us altogether past belief, did not the result of their labours, in many cases, remain to prove their extraordinary skill. For the purpose of securing to themselves all the benefits of their craft, the corporate bodies of free and accepted masons are found to have guarded with peculiar care the knowledge which they had themselves attained; gradually revealing it under oaths of profound secrecy to those who wished to become members of their community, and making it a perfect mystery to the public at large. It appears, also, that they either closely concealed, or even destroyed the calculations and working plans which they must have had to aid them in their labours; so that they have left few traces of the skill by which they performed their admirable works. On the diminution of papal influence in different countries, and on the increase of learning and industry among the inhabitants, the jealousy of the native sovereigns was awakened at the intrusion of bodies of foreigners, possessing privileges as wide, and rights as exclusive, as were those of the free-masons. The support derived by these companies from the papal see, being also more precarious, they gradually began to decline: so that, in consequence, in some places they dissolved their communities; in others they were expelled; until at last they ceased altogether to follow their profession, and nothing remained of this once powerful body but an empty name and formulary, which others have adopted and appropriated to their own use for the concealment of pursuits, which, if not positively beneficial, are at least innoxious to the world. The progress of architecture was for a while suspended on the approach of the thousandth year after the birth of our Saviour, owing to the very prevalent idea that that would be the period of his re-appearance, and of the destruction of the globe. It was not until the time had passed by, and men began to recover from their fright and torpor, that they could apply themselves to the repair of their churches and monasteries, or to the completion of those which had been left neglected at the period of general dismay. But, subsequently to this, we find the number of churches rapidly increasing, and many a stately pile may be traced as the work of the architects of that century. The Crusades too, which ensued in less than a century after the bygone millenium, greatly increased the revenues of the church, and were in consequence the means of augmenting the number of religious edifices in every Christian country. At the same period an improvement took place in civil architecture. The nobles who were bound to the Holy Land often sold privileges and enfranchisements to the cities under their control; and this producing an increase of wealth and independence to the citizens, they soon began to want, and to erect, edifices for civil purposes, which were often extensive and magnificent. In Lombardy, and in the cities of the Adriatic, were seen the first magnificent town halls; and later we may trace them in Germany. from thence we find them adopted in Belgium, Bruges, Ghent, Antwerp, and Amsterdam. We do not find that the free-masons, privileged as they were by the papal authority exerted on their behalf, could ever find access to the Greek empire; nor does it appear that the regions which fell under the sway of the Mohammedan powers were much indebted to Rome, or to the freemasons, for their architectural buildings, though they seem to have borrowed from Constantinople and from the Greeks. Where the Moorish kings held sway, we find the Christians, in Spain, to have copied their style of architecture; and it was not until the Catholics had acquired a decided superiority in that country, that the Gothic style of architecture began to prevail. We have already stated that the introduction of the arch was productive of great and important changes in Roman architecture. One of the features of the style which succeeded the ancient Roman was that which is now called groined vaulting, the idea of which must soon have presented itself to any one employed in the construction of a common cylindrical vault; since the intersection of two of the latter would produce the groined vault. The ribs of the groins were made to rest on columns, and the differences of character in that species of architecture which we are about to consider arose from the various modes of arranging this system of arches. The style of building which prevailed in Europe from the fall of the Roman empire till the sixteenth century, and which is marked by the consistent application of the pointed arch, has been classed under the general name of GOTHIC ARCHITECTURE. This name has been objected to, as being incorrect, and as conveying an erroneous idea of the origin and invention of the style to which it is appropriated; yet, however ill chosen the epithet may be, or however contemptuous the sense in which it was originally applied, the usage of it has become so confirmed through a succession of ages, and it is also now so difficult to find a more fitting appellation, that it seems altogether useless to attempt to explode it. "The architecture of the middle ages," and "Christian architecture," have been suggested as more expressive of the style in question; but both these terms are objectionable, and involve some degree of error. Perhaps "Pointed Architecture" may be considered the least exceptionable term, and may be used synonymously with the word "Gothic." It will not be uninteresting to place before our readers a few, out of the many theories which have been started as to the origin of pointed architecture-theories amid which, as it has been said, it is as easy to find the pole as to arrive at the truth. “Sir Christopher Wren was of opinion," says his son, "that what we now vulgarly call the Gothic, ought properly and truly to be named the Saracenic architecture refined by the Christians, which first of all began in the East, after the fall of the Greek empire, by the prodigious success of those people that adhered to Mahomet's doctrine, who out of zeal to this religion built mosques, caravanserais, and sepulchres, wherever they came. These they contrived of a round form, because they would not imitate the Christian figure of a cross, nor the old Greek manner, which they thought to be idolatrous, and for that reason all sculpture became offensive to them. They then fell into a new mode of their own invention. The quarries of great marble by which the vanquished nations of Syria, Egypt, and all the East had been supplied for columns, architraves, and great stones, were now deserted. The Saracens, therefore, were necessitated to adapt their architecture to such materials, whether marble or freestone, as every country readily afforded. They thought columns and heavy cornices impertinent, and might be omitted; and affecting the round form for mosques, they erected cupolas in some instances with grace enough. The holy war gave the Christians who had been there an idea of Saracen works, which were afterwards by them imitated in the West, and they refined upon it every day, as they proceeded in building churches." Lord Aberdeen supports Wren in this theory, and says, "If a line be drawn from the north of the Euxine through Constantinople to Egypt, we shall discover in every country to the eastward of this boundary frequent examples of the pointed arch, accompanied with the slender proportions of Gothic architecture; in Asia Minor, Syria, Arabia, Persia, from the neighbourhood of the Caspian through the wilds of Tartary; in the various kingdoms, and throughout the whole extent of India, and even to the furthest limits of China. It is true that we are for the most part unable to |