First Steps to Geometry.

(Continued from page 54.)

PROBLEM VI.

Echoes in Buildings.

THE application of the principles of reflection has been thought of great importance in the construction of buildings. All places intended

THROUGH a given point c, to draw a line for public speaking and the performance of parallel to a given line ▲ B.

music should be constructed in that form, and with those provisions, known to give a ready passage to sound without the interference of reverberation. In small apartments the form is of but little importance, so far as regards the production of echo, for the incident and reflected sounds so rapidly follow each other, that there is no perceptible interval between them in fact, they are brought to the ear as a single sound. In large buildings, on the other hand, in churches, theatres, and concertrooms, the echo is heard after the principal sound' has ceased; and if the building is so constructed as to return several echoes in very different times, the effect will be unpleasant. It is owing to this that in cathedrals the service is usually read in a sustained, uniform tone, rather that of singing than speaking, the voice being thus blended in unison with its echo. A good reader will time his syllables, if possible, so as to make one fall in with the echo of the last, which will thus be merged in the louder sound, and produce less confusion in his delivery.

It is very difficult to direct the architect in the construction of a building best suited for sustaining sound. One effect should certainly be sought, that of obtaining reflection; and one should be avoided, that of an echo from one sound, blending with a note of a different pitch.

Third Method.-When the parallel line is to avoided. be at a given distance c F.

From any two points E and D, in the line A B, as centres, and with cr as a radius, Draw G H touching these arcs, in 1 and x, and it will be the parallel required.

describe the arcs i and K.

(To be continued.)

Everything that can stifle a sound should be Windows, deep recesses, carpets, and curtains, are, in every respect, injurious to the propagation of sound. They have the effect of preventing reflection, which should always be promoted, as a means of increasing intensity. Particular forms have been sometimes recommended, as fit to reflect sounds; but if the laws governing the reflection of sound are the same as those which influence the direction of light, they can be of little service. It would be easy to arrange reflecting surfaces of a particular form, in such a manner, that the speaker being in one focus and the hearer in the other, the sound would have great intensity; but, under ordinary circumstances, it is required to convey sound of great intensity over the whole of a building, and not to concentrate the effect upon any one point.

But while the architect aids the reflection of sound, he must be careful to prevent the posPERPETUAL MOTION.-This vain delusion, if sibility of an echo. This is especially necesnot still in force, is at least as standing a sary in concert-rooms; for, as a number of fallacy still as ever. Joseph Hutt, a frame- notes may be struck in a short interval of time, work-knitter, in the enlightened town of it is possible that the echo of one may interfere Hinckley, professes to have discovered it, and only wants £20, as usual, to set it a-going.Builder.-[Joseph Hutt has got a rival; for one of our correspondents informs us that he has had "peptual mottion" working in a box since the first of June.-ED. DECORATOR'S ASSISTANT.]

with the original sound of another, and a constant discord would in this case afflict the ear of an auditor.-Higgins's Philosophy of Sound.

The improvements in Durham Cathedral are making most satisfactory progress.

Garden Decoration.

stantial for objects of ornament. We will venture to say, however, that no one design will be found without something to recommend it; and it is our intention to insert one or more of them occasionally, so as to comprise a rich assemblage of ideas on this department of rural architecture.

the park.

We are aware that ornamental buildings are much more sparingly introduced in garden scenery now, than they were a century ago, and, we think, very properly. It is in much better taste to dignify common useful edifices, seat, with a thatched roof, who was erected The above engraving represents a round such as cottages, lodges, barns, sheds, bridges, by the Duke of Marlborough, at White seats, &c., by better materials, better con- Knights, about the year 1812. It is formed trivance within, and better architectural entirely of straight branches of the maple and design without, than to throw away money on the larch, beneath a circular thatched dome; temples, grottoes, and root-houses; but, the rustic pillars support an architrave of taste though we allow that these useful objects and beauty, displayed in the most simple ought to be first attended to, we cannot materials. Thin slices from the heart of the consent that the others should be excluded; and, indeed, we think most of our readers will yew tree, form medallions, which are grafted agree with us that all exclusive plans are bad, symmetry as to produce a surprising effect; into small sprays of larchwood, with so much for the simple reason that they are exclusive. and the pebbled floor is disposed in leaves and Let a gentleman first attend to his own circles, with equal simplicity and grace. On dwelling-house, the residence of himself, and the back of this bower is a seat which fronts of those servants and domestic animals on which so much of his own enjoyments and comforts depend; for, till his own family is at ease, he cannot be expected to think much of SUSPENSION BRIDGES.-Suspension bridges the enjoyments of others. Let him next see appear to have been amongst the earliest conthat every human being that lives on his trivances for effecting passages across rivers, estates, and labours for him, or pays him rent, torrents, and ravines. The most ancient of is commodiously, conveniently, and comfort- these are generally met with in the East, ably lodged. After that, let him examine into although they have been discovered in other the improvements which may be made in the parts of the world. Humboldt mentions that, lodgings of the useful quadrupeds and other in South America, there are numerous bridges animals on his demesne, or on his tenanted lands; and, having satisfied his own conscience and the opinion of good men, in all these particulars, let him then turn to the pleasing task of adding ornament to utility; of superadding to works of art what the wise and beneficent Author of nature always adds to his works, something calculated to entice and invite.

of this description formed of ropes, made from the fibrous parts of the roots of the great American aloe (Agave Americana). These ropes, which are three or four inches in diameter, are attached on each bank to a rude framework composed of the trunk of the Schinus molle; where, however, the banks are flat and low, this framework raises the bridge so much above the ground as to prevent it from being accessible. To remedy this inconvenience, steps or ladders are, in these cases, placed at each extremity of the bridge, by ascending which, all who wish to pass over, readily reach the roadway, which is formed by covering the ropes transversely with small cylindrical pieces of bamboo. Suspension bridges formed of iron have been discovered in China, the most remarkable of which is the bridge Chukacha-zum, in Thibet, stretched over the Tehintchieu river, and situated about eighteen miles from Murichom. It is thus described in Turner's "Embassy to the Court of Thibet:"| "Only one horse is admitted to go over it at a time; it swings as you tread upon it, reacting at the same time with a force that impels you every step you take to quicken your pace. It may be necessary to say, in explanation of its construction, that on the five chains which support the platform, are placed several layers of strong coarse mats of bamboo, loosely put The communications which we propose to down, so as to play with the swing of the make upon this subject from time to time, we bridge; and that a fence on each side conwish to be considered in the light of hints and tributes to the security of the passenger." The ideas for these inviting superadditions: some date of the erection of this bridge is unknown of them may not be approved of, as being too to the inhabitants of the country, and they rustic; others, as being too finical or refined; even ascribe to it a fabulous origin. The some, as being paltry, and of temporary dura- length of the bridge appears to be about 150 bility; and others, as being too grave and sub-feet.

Copyright of Designs.

THE act 5 and 6 Vict., c. 100, which repealed all previously existing ones, extended to a considerable extent the period of copyright in designs.

III. Articles of manufacture wholly or chiefly of glass.

IV. Articles of manufacture
wholly or chiefly of earthenware.
V. Paper-hangings.
VI. Carpets.

VII. Shawls, where the design is applied solely by printing, or by any other process by which colours are or may hereafter be produced upon tissue or textile fabrics.

VIII. Shawls not comprised in Class VII. IX. Yarn, thread, or warp, the design being applied by printing, or by any other process by which colours are or may hereafter be produced.

X. Woven fabrics, composed of linen, cotton, wool, silk, or hair, or of any two or more of such materials, if the design be applied by printing, or by any other process by which colours are or may hereafter be produced upon tissue or textile fabrics; except the articles included in Class XI.

before publication. Piracy is punished by a penalty of not less than £5 nor more than £30, to be paid to the proprietor of the design, and to be recovered by an action of debt or for damages, or by summary proceeding before two justices.

THE ITINERARIUM, OR RAILWAY COMPASS.By this act the articles to which designs may The object of this invention is at all times to be applied are divided into thirteen classes: show to the engineer the speed of the engine, I. Articles of manufacture composed wholly the distance to the next station, and the exact or chiefly of any metal or mixed metals. position on the line, which will be useful at II. Articles of manufacture composed night, or in foggy weather. There is a chronowholly or chiefly of wood. meter, which will, of course, show the railway composed time. It will also register on paper a description of the journey, and the exact speed tracomposed velled during every mile. This paper may be taken off at the end of each journey, the date and number of engine marked on, and filed in the railway office. The apparatus has a dial, the circumference of which is divided into the number of miles on the railway, and all the stations are correctly marked down at the proper distances from each terminus. A finger or indicator points to that place on the dial occupied by the engine on the line of railway. There is a small finger, which revolves once in two miles, by which the engineer can ascertain his speed. There is also another small finger, which revolves once in sixty journeys, or about 10,000 miles, by means of which it can be ascertained what distance the engine has performed during a considerable period, say ten weeks; and as many engineers are paid by mileage, it would settle all disputes as to the distance run during the week or fortnight for which they receive their wages. Within the apparatus the speed and distance is registered. A long strip of paper is previously marked with perpendicular lines, which represent miles, and with horizontal lines, which represent minutes; and it is so arranged that one division of the perpendicular lines is wound on a cylinder when the engine has advanced one mile. Connected with the chronometer is an apparatus moving a pencil, which marks the paper cross one division line in one minute of time; by these means (according to the perpendicular or diagonal mark on the paper) the stoppage and velocity of the engine can be precisely ascertained. The itinerarium is moved by means of a separate wheel running on the rail, and is not affected by breaks or slipping, &c.; it is placed in a convenient place, so that the engineer may readily see it, and at night it is illuminated. The Manchester and Leeds Railway Company have allowed the inventor to test the experiment on one of their engines, and several trips have been made with the apparatus, which fully realised the expectations formed concerning it. Manchester Express.

XI. Woven fabrics composed of linen, cotton, wool, silk, or hair, or any two or more of such materials, if the design be applied by printing, or by any other process by which colours are or may hereafter be produced upon tissue or textile fabrics, such woven fabrics being or coming within the description technically called furnitures, and the repeat of the design whereof shall be more than twelve inches by eight inches.

XII. Woven fabrics not comprised in any preceding class.

XIII. Lace, and any article of manufacture or substance not comprised in any preceding class.

The act gives to the proprietor of a design, not previously published, the sole right of applying it to ornamenting articles of the first, second, third, fourth, fifth, sixth, eighth, and eleventh classes, for three years; to articles of the seventh, ninth, and tenth, for nine months; and to articles of the twelfth and thirteenth classes for twelve months, whether such design be applicable for the pattern, or for the shape and configuration, or for the ornament of the articles, or for two or more such purposes, and by whatever means the ADDITION TO THE BRITISH MUSEUM.-The design may be applicable, whether by print- sculptures in honour of Nimrod and his vicing, or by painting, or by embroidery, or by tories, which were lately dug up at Ninevah, weaving, or by sewing, or by modelling, or by have been deposited in the British Museum. casting, or by embossing, or by engraving, or They are well worthy of a visit, being fine by staining, or by any other means whatso- specimens of ancient art. The material in ever, manual, mechanical, or chemical, sepa- which they are wrought is gypsum, or soft rate or combined. The benefits of copyrights plaster stone, on which the effects of time are of designs are made to depend on registration | scarcely visible.