ANY two sides of a right-angled triangle being given, to find the third side. 1. When the base and perpendicular are given, to find the hypotenuse. Add the square of one of the legs to the square of the other, and the square root of the sum will be equal to the hypotenuse. 2. When the hypotenuse and one of the sides are given, to find the remaining one. Subtract the square of the given side from the square of the hypotenuse, and the square root of the remainder will be equal to the other side. Example 1.-The height of a tower, standing close by the edge of a ditch, is 54 ft., and the 1425) 8400 7125 14308) 127500 114464 13036 Therefore the string must be rather more than 714 ft. long. Example 2.-The height of a precipice, standing close by the side of a river, is 103 ft., and a line of 320 feet will reach from the top of it to the opposite bank; required the breadth of the river? 21791 Dissolve three pounds and a half of clear Therefore the width of the river must be pale resin and one gallon of oil of turpentine; 303 ft. nearly. (To be continued.) IRON IN THE ROMAN STATES.-M. Gauthier, a French engineer and manager of the iron works of Terni, in the Papal States, has just discovered, after long researches, an iron mine of great richness, extending from Monte Nero to the town of Gualdo Tadini. The ore is said to yield sixty per cent. of pure iron of excellent quality. There are numerous watersources in the vicinity, which will serve to work the machines necessary for working the ore. This new mine and that of Tolfa will, it is said, supply all the iron which the Roman States can require, including what will be necessary for the projected iron bridges and railways. ARTISTS' OIL-COLOUR CAKES.-Grind the required colour with oil of turpentine, in which has been dissolved, in the cold, about one-sixth of its weight of powdered mastic; let them dry, then place the stone over a slow charcoal fire, so as to soften the colour, and add a sufficient quantity of a warm solution of spermaceti in half its weight of poppy-oil, to make the mass into a proper paste; remove the heat, work until it begins to harden, then form the mass into pieces, and mould them into cakes. When wanted for use, rub them down with poppy, nut, or linseed oil, and turpentine, as required. or, mix four pounds of clear Venice turpentine and five pounds of oil of turpentine. N.B. Both are good common varnishes for wood or metal. 43. Engravers' Transfer Varnish. Take six ounces and a half of mastic in tears; twelve ounces and a half of resin; and of genuine pale Venice turpentine and sandarach, of each, twenty-five ounces. Dissolve, add one quart of turpentine varnish, agitate well, and strain. 44. Engravers' Stopping-Out Varnish. Make lamp-black into a paste with turpentine. 45. Wainscot Varnish. Same as mahogany varnish (No. 41, ante), but use paler gum and oil. 46. Ground Varnish for Transparencies. Dissolve wax in oil of turpentine. THE DONCASTER RACE CUP.-The Doncaster Cup this year was executed after Mr. Cotterill's design, and embodies an incident taken from the old chronicle records of the battle of Ascalon, The cover has an equestrian group, representing Richard Coeur de Lion battling with Saracens. The cup, itself, is richly decorated in the Italian style. Glue. 4. Hatmakers' Glue. From the tendons of the legs of neat cattle and horses. It is brown, opaque, and soft; grows moist in damp weather, but does not render the felt brittle. 5. Fish Glue. Is made in like manner from various membranous and solid parts of cetaceous animals. 6. Parchment Glue. PROFESSOR SCHÖENBEIN'S IMPROVED PAPER. GLUE is an inspissated animal jelly or gelatine, principally prepared from the parings and waste pieces of hides and skins, the refuse of tanneries, and the tendons and other offal of slaughter-houses. These should be carefully preserved from damp, being very liable to decomposition. When required for use, they should be steeped for about fourteen or fifteen days in milk of lime (slaked lime mixed up Shreds or shavings of parchment, vellum, with water), and then drained and dried. white leather, &c., dissolved by boiling in This forms the process of" cleaning," or pre-water, forming a nearly colourless glue. paration;" but before being converted into glue, the materials are generally steeped in weak milk of lime, well rinsed in water, and exposed to the air for twenty-four hours. In a letter from Professor Schöenbein to M. After this they are placed in a copper boiler, Dumas, dated March 28th, 1840, the author two-thirds filled with water, and furnished communicated a new method he has diswith a false bottom, perforated so as to pre-covered, by means of which the following provent them from burning, and as much is piled perties may be given to the paper in common on as will fill the vessel and rest on the top of use:-"1. Prepared paper has much more it. Heat is next applied, and gentle boiling tenacity and greater consistency than common continued until the liquor on cooling forms a paper. 2. When dipped in water it does not firm gelatinous mass. The clear portion is then lose its consistency, but is affected as parchrun off into another vessel, where it is kept ment would be. 3. It receives with equal heated by means of a water-bath, and allowed facility both writing and printing ink. 4. It to repose for some hours to deposit, when it is does not require sizing to render it suitable run into the congealing boxes, and placed in a either for writing or printing. 5. The injurious cool situation. The next morning the cold effects produced by the chloride of lime are gelatinous masses are turned out upon boards avoided in prepared paper." M. Schöenbein wetted with water, and are cut horizontally into states that his process is simple, inexpensive, thin cakes with a stretched piece of brass wire, and easy of application, and the new paper and then into smaller cakes with a moistened flat offers many advantages, particularly for bank knife. These cakes are next placed upon notes and for paper-hangings. The vegetable nettings to dry, after which they are dipped fibre of this paper renders it possible to make one by one into hot water, and slightly rubbed of it a substance as transparent as glass, and with a brush wetted with boiling water, to give impermeable to water. The author has made them a gloss; they are lastly stove-dried for of it bottles, balloons, &c., the sides of which sale. During this time, the undissolved portion may be made as thin as a plate of mica. of skins, &c., left in the copper is heated with Another property of this paper is, that it fresh water, and the whole operation is re- developes a very energetic electric force. By peated again and again, as long as any gela-placing some sheets on each other, and simply tinous matter can be extracted. The first runnings produce the palest and best glue. The refuse matter from the tanners and leather-dressers yields, on the average, when dried, 50 0-0 of its weight of glue. The following are varieties: rubbing them once or twice with the hand, it ANTIQUE FIRE-PLACES.-In pulling down the| deanery at Lincoln, two very ancient open fire-places and chimneys have been discovered, which are conjectured to be part of the original building of Dean Gravesend in 1254. Both are of wrought stone, with tiled backs, and have been made for the burning of wood upon the hearth; and each chimney forms the half of a four-sided pyramid, with the apex ending in the ceiling of the rooms. Correspondence. STEAM-BOILER EXPLOSIONS. To the Editor of the DECORATOR'S ASSISTANT. SIR,-I perfectly agree with your corres- I believe it to be no uncommon thing for steam-engines to be worked on board vessels, having no one on board capable of performing the office of engineer; but if a certificate by the maker of the boiler were to be placed in some very conspicuous position in each vessel conveying passengers, stating in a plain and understandable manner the pressure the boiler is capable of; also a steam-gauge, showing the actual pressure upon the boiler, which should likewise have a safety-valve, over which no person on board could have any control, I think some of the passengers would always be on the look-out for their own personal safety, keeping a check upon the engineer, or rather labourer, employed to work the engine. I am, Sir, your obedient servant, London, Sept. 12, 1847. PHILO-SAFETY. [The suggestion of our correspondent appears to us to be a very good and practicable one, and we cannot too earnestly recommend such a method of preventing disaster; but, to our thinking, a great deal of risk is incurred through the state of the boiler, which, by being out of repair or worn out, is liable at any moment to explode. This cannot be remedied in the manner "Philo-Safety" proposes, and therefore we think that nothing could be better than a regularly-appointed inspector, whose express duty it should be, at certain intervals, to examine into and report upon the state of the boilers of the river steam-boats.-EDITOR DECORATOR'S ASSISTANT.] Review. THE CHEMIST. Edited by Messrs. Watts and Dr. P. J. Murphy.-London: Geo. Peirce, 310, Strand. No. XCIII. This is an excellent number of an oldestablished magazine, containing a vast number of articles on chemistry, experimental, agricultural, and manufactural; as also pharmacy, materia medica, therapeutics, &c., selected with great discrimination and ability. WAXED PAPER.-This paper, which is employed to form extemporaneous steam or gaspipes, &c., is prepared by placing cartridge paper on a hot iron plate, and rubbing it over with bees'-wax. Notices to Correspondents. Part IV. of the DECORATOR'S ASSISTANT, in an embellished Wrapper, is now ready, price Sevenpence. Parts I. and II. still continue on sale. In consequence of the great and increasing demand for the Back Numbers of the DECORATOR'S ASSISTANT, Subscribers are respectfully requested to complete their Sets without delay. We beg to thank those Correspondents who have pointed out omissions in the "Illustrated Glossary of Technical Terms used in Architectural and Interior Decoration," now publishing in this Work, and also to inform them that such will be inserted in an Appendix, which we intend to give at the end. We shall, also, feel obliged by Correspondents favouring us with any corrections, additions, &c. NOTICE TO OUR READERS AND CORRESPONDENTS.-The article on "Varnishes," now publishing in the DECORATOR'S ASSISTANT, being intended to be rendered as complete as possible, such of our Readers as may be in possession of information or receipts, will confer a favour on us by forwarding them, and at the same time assist in disseminating useful knowledge, for which, at present, no other channel exists. QUERIES. [In order to collect as much useful information as possible, Required-A receipt for making ink to mark cases with.- Required-1. A receipt for a composition to make flexible REGIOMONTANUS (Manchester).-Such a step on our part J. B.-In such a handwriting as yours, use about double the ness. VOLTA. Your friend was perfectly right; the ancients did employ sponges for the purpose of painting. Adams, Curious. QUESTIONS TOO TRIVIAL OR INAPPROPRIATE.-H., John To SIGN-PAINTERS, &c.-Designs for Letters, Ornaments, &c., made, and, if necessary, engraved, on the most reasonable terms, with punctuality and despatch. particulars, &c., address (if by letter, post paid) to Mr. Wm. Gibbs, Ornamental Draughtsman and Engraver, at the DECORATOR'S ASSISTANT Office, 17, Holywellstreet, Strand, London. For London: Published at the Office of the SPORTING LIFE, 17, Holywell-street, Strand (where all communications to the Editor are to be addressed); and to be had of all Booksellers.-Saturday, September 25, 1847. Printed by W. COOLE, Lumley Court, Strand. |