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This is effected with pumice-stone and tripoli earth. The pumice-stone must be reduced to an impalpable powder, and put upon a piece of serge moistened with water: with this rub lightly and equally the varnish substance. The tripoli must also be reduced to a very fine powder, and put upon a clean woollen cloth, moistened with oliveoil, with which the polishing is to be performed. The varnish is then to be wiped off with soft linen, and when quite dry cleaned with starch or Spanish white, and rubbed with the palm of the hand. Process for giving various Objects a Pearly Lustre. To produce the iridescence of mother-of-pearl on stone, glass, metal, resin, paper, silk, leather, etc., Reinsch adopts the following process: 2 parts of solution of copal, 2 parts of that of sandarac, and 4 parts of solution of Damara resin (equal parts of resin and absolute alcohol) are mixed with half their volume of oil of bergamot or rosemary. This mixture is to be evaporated to the thickness of castor-oil. If this varnish be then

drawn, by means of a feather or brush, over the surface of some water, it will form a beautiful iri. descent pellicle. This film is now to be applied to the objects which are to be rendered iridescent. The vessel in which the water is contained, on which the pellicle has been produced, must therefore be as large as or larger than these objects. The water should have about 5 per cent. of pure solution of lime added to it; its temperature should be kept at about 72°. The objects are dried in the air.

To Prevent the Formation of Fungi in Timber.

The following paint has been found successful: Flour of sulphur, 3088 grs.; common linseed-oil, 2084 grs.; refined oil of manganese, 463 grs.

Prevention of Rotting of Wood.

Take 50 parts of rosin, 40 of finely powdered chalk, 300 parts or less of fine, white, sharp sand, 4 parts of linseed-oil, 1 part of native red oxide of copper, and 1 part of sulphuric acid. First heat the rosin, chalk, sand and oil, in an iron boiler; then add the oxide, and, with care, the acid. Stir the composition carefully, and apply while hot. If too thick, add more oil. This coating, when cold and dry, forms a varnish hard as

stone.

CEMENTS.

Hydraulic Mortar.

Rosendale Cement

Slaked lime, 1 bu.; calcined clay, 14 bu.; washed Is made by calcining the limestone or cementsand, 14 bu.

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Sand, 100 lbs.; marble-dust, 100 lbs. ; freestone, 100 lbs.; red lead (minium), 3 lbs. ; litharge, 3 lbs.; linseed-oil, 21 pts.

Genuine Roman Cement, Or pozzuolana, from the neighborhood of Vesuvius, is a peculiar mixture of silica, clay, and lime, which has been calcined by the volcano. It

is used mixed with lime and sand. The following is the formula of Vitruvius: 12 parts pozzuolana well powdered, 6 sharp sand well washed, 9 rich lime, recently slaked. It has the power of rapidly hardening under water.

Artificial Portland Cement.

One hundred lbs. of pure, dry chalk is moistened and ground in a mill with excess of water; to this is added 1374 lbs. of pure alluvial clay, and the two are thoroughly incorporated. The mixture is made into balls, which are dried and caloined in an ordinary lime-kiln.

stone, found above the Potsdam sandstone and below the Utica slate of the New York survey. It iron, with some salts of potash and soda. consists of silica, magnesia, alumina, oxide of stone is found in eastern New York, New Jersey, Pennsylvania and Virginia.

Artificial Hydraulic Cements

The

Are made 1, by combining thoroughly slaked lime with from 10 to 40 per cent. unburnt clay, and burning the mixture in a kiln; 2, by grinding clay and chalk as directed above for Portland Cement; 3, by making artificial pozzuolana from calcareous sand and clay, and calcining it; 4, by the use of silicate of soda: 8 or 10 per cent. of a solution of the consistence of thin syrup, is to be mixed with mortar of fat lime.

Cement for Rooms.

A coat of oxide of zinc (zine white) mixed with size, is applied to the wall, ceiling or wainscot; over this, one of chloride of zinc, prepared in the same way. The two unite and form a cement smooth and polished as glass.

Parolie Cement.

whey out, dry and pulverize, and warm over■ Take unsalted curd of skimmed milk, press the stove. Of this, 90 parts; caustic quicklime, in fine powder, 10 parts; powdered camphor, 1 part Mix intimately and keep in small bottles corked perfectly tight. To use, mix the required amount with water with a palette-knife, and apply immediately.

To make Cement for Floors.

Earthen floors are commonly made of loam; and sometimes, especially to make malt on, of lime and brook-sand, and gun-dust or anvil-dust from the forge. The manner of making earthen

floors for plain country habitations is as follows: take lime and coal-ashes well sifted, with a small quantity of loam clay; mix the whole together and temper it well with water, making it up into a heap; let it lie a week or 10 days and then temper it over again. After this, heap it up for 3 or 4 days, and repeat the tempering very high till it becomes smooth, yielding, tough and gluey. The ground being then levelled, lay the for therewith about 24 or 3 in. thick, making it smooth with a trowel. The hotter the season is, the better; and when it is thoroughly dried, it will make the best floor for houses, especially malt-houses.

Pew's Composition for Roofing Buildings. Take the hardest and purest limestone (white marble is to be preferred), free from sand, clay or other matter; calcine it in a reverberatory furnace, pulverize and pass through a sieve. One part, by weight, is to be mixed with 2 parts of clay well baked and similarly pulverized, conducting the whole operation with great care. This forms the first powder. The second is to be made of 1 part of calcined and pulverized gypsum, to which is added 2 parts of clay baked and pulverized. These two powders are to be combined and intimately incorporated, so as to form a perfect mixture. When it is to be used, mix it with about of its weight of water, added gradually, stirring the mass well the whole time, until it forms a thick paste, in which state it is to be spread like mortar upon the desired surface. It becomes in time as hard as stone, allows no moisture to penetrate, and is not cracked by heat. When well prepared it will last any length of time. When in its plastic or soft state, it may be colored of any desired tint. Zeiodelite.

part

Zeiodelite is made by mixing together 19 lbs. of sulphur and 42 lbs. of pulverized stoneware and glass. The mixture is exposed to a gentle heat, which melts the sulphur, and then the mass is stirred till it becomes thoroughly homogeneous, when it is run into suitable moulds and allowed to cool. This preparation is proof against acids in general, whatever their degree of concentration, and will last an indefinite time. It melts at about 248°, and may be re-employed without loss of any of its qualities, whenever it is desirable to change the form of an apparatus, by melting at a gentle heat and operating as with asphalte. At 230° it becomes as compact as stone, and therefore preserves its solidity in boiling water. Slabs of zeiodelite may be joined by introducing between them some of the paste heated to 392°, which will melt the edges of the slabs, and when the whole becomes cold it will present one uniform piece. Chambers lined with zeiodelite, in place of lead, the inventor says, will enable manufacturers to produce acids free from nitrate and sulphate of lead. The cost will be only one-fifth the price of lead. The compound is also said to be superior to hydraulic lime for uniting stone and resisting the action of water.

To make Cement for Canals. Take 1 part of iron filings, reduced to sifted powder, 3 parts of silica, 4 parts of red clay, the same quantity of pulverized brick, and 2 parts of hot lime; the whole measured by weight and not by bulk.

Put the mixture into a large wooden tub, in order that nothing foreign may be introduced into it. If sufficient water is poured out to extinguish the lime and give a degree of liquidness to the cement, and if all the component parts are briskly stirred, a great degree of heat will be emitted from

the lime, and an intimate union formed by the heat.

Cement for Cast-Iron.

In mixing cement for cast-iron, put 1 oz. of sal ammoniac to each hundredweight of borings, and use it without allowing it to heat. Multiply the length of any joint in ft. by the breadth in in., by the thickness in eighths, and by 3; the product will be the weight of dry borings, in lbs. avoirdupois, required to make cement to fill that joint nearly.

Or, take of sal ammoniac, 2 oz.; flowers of sulphur, 1 oz.; clean cast-iron borings or filings, 16 oz.: mix them well in a mortar, and keep them dry. When required for use, take 1 part of this powder and 20 parts of clean iron borings or filings, mix thoroughly in a mortar, make the mixture into a stiff paste with a little water, and apply it between the joints, and screw them together. A little fine grindstone sand added improves the

cement.

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Pack it close in an iron vessel, and cover with water.

For Mending Iron Retorts.

Fifteen lbs. fire-clay, 1 lb. saleratus, with water sufficient to make a thick paste. This mixture must be applied to the broken part of the retort when the retort is at a good working heat; after this has been done, cover it with fine coal dust, and charge the retort for working.

Cement for Rock-work and Reservoirs. Where a great quantity of cement is wanted for coarser uses, the coal-ash mortar (or Welsh tarras) is the cheapest and best, and will hold extremely well, not only where it is constantly kept wet or dry, but even where it is sometimes dry and at others wet; but where it is liable to be exposed to wet and frost, this cement should, at its being laid on, be suffered to dry thoroughly before any moisture has access to it; and, in that case, it will likewise be a great improvement to temper it with the blood of any beast.

The mortar must be formed of 1 part lime and 2 parts of well-sifted coal-ashes, and they must be thoroughly mixed by being beaten together; for on the perfect commixture of the ingredients the goodness of the composition depends.

To make Mortar.

Mortar is composed of quicklime and sand, reduced to a paste with water. The lime ought to be pure, completely free from carbonic acid, and in the state of a very fine powder; the sand should be free from clay, partly in the state of fine sand, and partly in that of gravel; the water should be pure, and, if previously saturated with lime, so much the better. The best proportions are 3 parts of fine, and 4 parts of coarse sand, 1 part of quicklime, recently slaked, and as little water as possible. There should always be enough water added at first; if water is added after the slaking has begun, it will be chilled and the mortar lumpy.

The addition of burnt bones improves mortar by giving it tenacity and renders it less apt to crack in drying; but they ought never to exceed of the lime employed.

When a little manganese is added to mortar, it acquires the important property of hardening

under water; so that it may be employed in constructing those edifices which are constantly exposed to the action of water. Limestone is often combined with manganese; in that case it becomes brown by calcination. Tunisian Cement.

This is composed of 3 parts of lime, 1 of sand, and 2 of wood-ashes; these ingredients are mixed up with oil and water alternately, till they compose a paste of the desired consistency.

Water-cement, or Stucco.

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A New Cement.

Take 56 lbs. of pure coarse sand, 42 lbs. of pure Another.-Glue, 12 oz.; water, sufficient to disfine sand; mix them together, and moisten them solve it; add 3 oz. of rosin, melt them together, thoroughly with lime-water; to the wetted sand and add 4 parts of turpentine or benzine. This add 14 lbs. of pure fresh-burnt lime, and while beat-should be done in a carpenter's glue-pot, to avoid ing them up together add, in successive portions, burning. 14 lbs. of bone-ash. The quicker and more perfectly these materials are beaten together, and the sooner they are used, the better will be the cement; for some kinds of work it will be better to use fine sand alone, and for others coarse sand, remembering the finer the sand is the greater quantity of lime is to be employed.

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M. Edmund Davy prepares a new cement, which is well spoken of, by melting in an iron vessel equal parts of common pitch and gutta-percha. It is kept either liquid under water, or solid to be melted when wanted. It is not attacked by water, and adheres firmly to wood, stone, glass, porcelain, ivory, leather, parchment-paper, feathers, wool, cotton, hemp, and linen fabrics, and even to varnish.

Aquaria Cement.

One part, by measure, of litharge; 1 part plaspowdered rosin; mix all together. This may be ter of Paris; 1 part fine beach-sand; part fine kept for years, while dry, in a well-corked bottle; when used, make in a putty with boiled linseedoil; a little patent dryer may be used; it will stand water at once, either salt or fresh.

New Gutta-percha Cements.

Turkish Cement for Joining Metals, Glass, etc. Dissolve mastic in as much spirit of wine as will suffice to render it liquid; in another vessel dissolve as much isinglass (which has been pre-fabrics: Gutta-percha, 40 lbs. ; caoutchouc, 3 lbs.; For uniting sheet gutta-percha to silk or other viously soaked in water till it is swollen and soft) shellac, 3 lbs.; Canada balsam, or Venice turpenin brandy as will make 2 oz. by measure of strong tine, 14 lbs. ; liquid styrax, 35 lbs. ; gum mastic, glue, and add two small bits of gum-galbanum or ammoniacum, which must be rubbed or ground 4 lbs.; oxide of lead, 1 lb. till they are dissolved; then mix the whole with a sufficient heat; keep it in a phial stopped, and when

it is to be used set it in hot water.

Solution of India-rubber.

A solution of caoutchouc, or India-rubber, for repairing india-rubber shoes, is prepared in the following manner: Cut 2 lbs. of caoutchouc into thin, small slices; put them in a vessel of tinned sheet-iron, and pour over 12 to 14 lbs. of sulphide of carbon. For the promotion of solution place the vessel in another containing water previously heated up to about 86° Fahr. The solution will take place promptly, but the fluid will thicken very soon, and thus render the application difficult, if not impossible. In order to prevent this thickening and difficulty, a solution of caoutchouc and rosin (colophony) in spirits of turpentine must be added to the solution of caoutchouc in sulphide of carbon, and in such quantity that the mixture obtains the consistency of a thin paste. The solution of caoutchouc and rosin in spirit of turpentine should be prepared as follows: Cut 1 lb. of caoutchouc into thin, small slices; heat them in a suitable vessel over a moderate coal fire, until the caoutchouc becomes fluid; then add lb. of powdered rosin, and melt both materials at a moderate heat. When these materials are perfectly fluid, then gradually add 3 or 4 lbs. of spirit of turpentine in small portions, and stir well. By the addition of the last solution, the rapid thickening and hardening of the compound will be prevented, and a mixture obtained fully answering the purpose of gluing together rubber surfaces, etc. Marine Glue.

Out 3 parts India-rubber into small pieces, and

For uniting sheet gutta-percha to leather, as soles of shoes, etc.: Gutta-percha, 50 lbs.; Venice turpentine, 40 lbs.; shellac, 4 lbs.; caoutchouc, 1 lb.; liquid styrax, 5 lbs.

Metallic Cement.

A metallic cement, which answers for all purposes and becomes hard in the heat, may be ob tained in the following way: One hundred parts of oxide of zinc, with the same quantity of sulphate of lead, are triturated with 30 parts of linseed-oil, and then a mixture consisting of 100 parts of black oxide of manganese and 100 parts of peroxide of iron added until the mass forms a stiff dough. This is beaten in a mortar for 12 hours, during which the remainder of the above mixture of iron and manganese is added by degrees. The goodness of the cement may be recognized by its not crumbling when rolled out between the fingers.

Cement for Stoneware, by M. Heller. Gelatine is allowed to swell in cold water, the jelly warmed, and so much recently-slaked lime added as is requisite to render the mass sufficiently thick for the purpose. A thin coating of this cement is spread while warm over the gently-heated surfaces of fracture of the articles, and let dry under a strong pressure. What oozes out is removed directly with a moist rag.

Yates' Water-proof Cement.

and dissolve them in mild ale over a slow fire, in Take of the best glue 4 oz.; of isinglass, 2 oz., a common glue-kettle, to the consistency of strong glue, when 14 oz. of well boiled linseed-oil must. be gradually added, and the whole be well mixed by stirring. When cold and made into cakes it

directions in the preceding article, and having beaten the isinglass into small bits, and reduced the glue to the same state, pour the solution of the gums upon them, and melt the whole in a vessel well covered, avoiding so great a heat as that of boiling water. When melted, strain the glue through a coarse linen cloth, and then put it again over the fire, adding about 1 oz. of powdered glass.

resembles India-rubber. When wanted for use, dissolve a piece of it in a proportionate quantity of ale. This cement is applicable to all joints of wood, to join earthenware, china, glass. It is an excellent cement for leather, for harness, bands for machinery, etc. The joints of these are to be prepared as if for sewing, the cement to be applied hot, laying a weight upon each joint as it is made, in which state it is to be left 6 hours, when the joints will be found nearly as firm as if they This preparation may be best managed by hangwere of an entire piece. By adding a little towing the vessel in boiling water, which will prevent to the above, you have an excellent cement for leaks in casks, etc., etc. Common Cement for Joining Alabaster, Marble, Porphyry, and other Stones.

the matter burning to the vessel, or the spirit of wine from taking fire, and indeed it is better to use the same method for all the evaporation of nicer glues and sizes; but, in that case, less water than the proportion directed, should be added to

the materials.

Another Method.

Take of beeswax 2 lbs., and of resin 1 lb. ; melt them, and add 14 lbs. of the same kind of matter, powdered, as the body to be cemented is composed of, strewing it into the melted mixture, and stir- A very strong glue, that will resist water, may ring them well together, and afterwards kneading be also made by adding lb. of common glue, or the mass in water, that the powder may be thor-isinglass glue, to 2 qts. of skimmed milk, and then oughly incorporated with the wax and resin. The evaporating the mixture to the due consistence of proportion of the powdered matter may be varied the glue. where required, in order to bring the cement To make Parchment Glue. nearer to the color of the body on which it is employed.

This cement must be heated when applied, as also the parts of the subject to be cemented together, and care must be taken, likewise, that they may be thoroughly dry.

To make Lutes.

Take 1 lb. of parchment, and boil it in 6 qts. of water, till the quantity be reduced to 1 qt.; strain off the fluid from the dregs, and then boil it again till it be of the consistence of glue.

The same may be done with glovers' cuttings of leather, which make a colorless glue, if not burnt in the evaporation of the water.

A very Strong Compound Glue.

Take common glue in very small or thin bits, and isinglass glue; infuse them in as much spirit of wine as will cover them, for at least 24 hours. Then melt the whole together, and, while they are over the fire, add as much powdered chalk as will render them an opake white.

The infusion in the spirit of wine has been directed in the recipes given for glue; but the remark on the use of it in one of the preceding articles will hold good also in this, and the mixtur may be made with water only.

To make Compound Glue.

These are used for securing the juncture of vessels in distillations and sublimations. For the distillation of water, linen dipped in a thin paste of flour and water is sufficient. A lute of greater security is composed of quicklime, made into a paste with the whites of eggs. For the security of very corrosive vapors, clay finely powdered and sifted, made into a paste with boiled linseed-oil, must be applied to the juncture, which must be afterwards covered with slips of linen, dipped in the paste of quicklime and the whites of eggs. The lute must be perfectly dried before the vessels are used, or else the heat may cause it to dry too quickly, and thereby cause the lute to crack. If this be the case, it is repaired by applying fresh Take very fine flour, mix it with white of eggs lute in the cracks, and suffering it to dry gradu-isinglass, and a little yeast; mingle the materials, ally. Vessels which are to be exposed to the naked fire are frequently coated to resist the effects of the heat, the best coating for which purpose consists in dissolving 2 oz. of borax in 1 pt. of boiling water, and adding to the solution as much slaked lime as is necessary to form a thin paste. The vessel must be covered all over with it by means of a painter's brash, and then suffered to dry. It must then be covered with a thin paste of linseed-oil and slaked lime, except the neck. In 2 or 3 days it will dry of itself, and the retort will then bear the greatest fire without cracking. The cracks of chemical vessels may be secured by

the second lute.

To make Portable Glue.

Take 1 lb. of the best glue, boil and strain it very clear; boil likewise 4 oz. of isinglass, put it in a double glue-pot, with lb. of fine brown sugar, and boil it pretty thick; then pour it into moulds; when cold, cut and dry them in small pieces. This glue is very useful to draughtsmen, architects, etc., as it immediately dilutes in warm water, and fastens the paper without the process of damping.

To make Glue that will Resist Moisture. Dissolve gum sandarac and mastic, of each, 2 oz., in 1 pt. of spirit of wine, adding about 1 oz. of clear turpentine. Then take equal parts of isinglass and parchment glue, made according to the

beat them well together; spread them, the batter being made thin with gum-water, on even tin plates, and dry them in a stove, then cut them out for use. To color them, tinge the paste with Brazil, or vermilion for red; indigo or verditer, etc., for blue; saffron, turmeric, or gamboge, etc., for yellow.

To make Isinglass Glue.

This is made by dissolving beaten isinglass in water by boiling, and having strained it through a coarse linen cloth, evaporating it again to such a consistence, that, being cold, the glue will be perfectly hard and dry.

A great improvement is made in this glue by adding spirit of wine or brandy after it is strained, and then renewing the evaporation till it gains the due consistence.

To make Isinglass Size.

This may also be prepared in the manner above directed for the glue, by increasing the proportion of the water for dissolving it, and the same holds good of parchment size. A better sort of the common size may be likewise made by treated cuttings of glovers' leather in the same manner.

To make Flour Paste.

Paste is formed principally of wheaten flour boiled in water till it be of a glutinous or viscid

consistence. It may be prepared with those in- | the acid is added, the vessel is to be taken from gredients simply for common purposes; but when the fire, and left to cool. it is used by bookbinders, or for paper-hangings to rooms, it is usual to mix a fourth, fifth, or sixth of the weight of the flour of powdered resin; and where it is wanted still more tenacious, gum arabic or any kind of size may be added.

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Take 1000 lbs. of starch, moisten with a mixture of 300 lbs. of water, and 2 lbs. of nitric acid, allow it to dry spontaneously, and heat for 1 or 2 hours in stoves, at a temperature of 212° to 230° Fahr.

Preparing Glue for Ready Use..

1. To any quantity of glue use common whiskey insteady of water. Put both together in a bottle, cork it tight, and set it for 3 or 4 days, when it will be fit for use without the application of heat. Glue thus prepared will keep for years, and is at all times fit for use, except in very cold weather, when it should be set in warm water before using, To obviate the difficulty of the stopper getting tight by the glue drying in the mouth of the vessel, use a tin vessel, with the cover fitting tight on the outside to prevent the escape of the spirit by evaporation. A strong solution of isinglass, made in the same manner, is an excellent cement

for leather.

2. Take of best white glue, 16 oz.; white lead, dry, 4 oz.; rain-water, 2 pts.; alcohol, 4 oz. With constant stirring dissolve the glue and lead in the water by means of a water-bath. Add the alcohol, and continue the heat for a few minutes. Lastly, Four into bottles while it is still hot.

Liquid Glue.

Take 2 and 1-5th lbs. of glue, and dissolving it in 2 and 1-9th pts. of water in a glazed pot over a gentle fire, or, what is better, in the water-bath, stirring it from time to time. When all the glue is melted, 7 oz. Av. of nitric acid (spec. grav. 1-32) are to be poured in, in small quantities at a time. This addition produces an effervescence, owing to the disengagement of hyponitric acid. When all

Another. Dissolve the best isinglass in the strongest (glacial) acetic acid. Bottle Cement.

Resin, 15 parts; tallow, 4 (or wax, 3) parts; highly dried red ochre, 6 parts; or lampblack sufficient to give color.

Diamond Cement.

Isinglass, 1 oz.; distilled water, 5 oz.; dissolve and boil down to 3 oz.; add 1 oz. of alcohol, boil for a minute or two. Strain, and while hot add oz. of milky emulsion of gum ammoniae, and 5 drs. of tincture of mastic.

Oxychloride of Zinc Cement.

In liquid chloride of zinc, of 50° to 60° Beaumé, dissolve 3 per cent. of borax or sal ammoniac; add oxide of zinc (zinc white) until the mass is of proper consistence. This cement, when hard, becomes as firm as marble. It may be cast into moulds like plaster, as used in Mosaic work. Bird Lime.

Boil the middle part of the holly 7 or 8 hours in water; drain it, and lay it in heaps in the ground, covered with stones, for 2 or 3 weeks, till reduced to a mucilage. Beat this in a mortar, wash it in rain-water, and knead it till free from extraneous matters. Put it into earthen pots, and in 4 or 5 days it will be fit for use. An inferior kind is made by boiling linseed-oil for some hours, until it becomes a viscid paste.

Transparent Cement.

Dissolve 75 parts India-rubber in 60 parts of chloroform or benzine, and add to the solution 15 parts of mastic. Another. - Balsam of fir is a strong cement when not exposed to heat. It is to be warmed and applied to the glass, itself previously warmed. It is used for cementing lenses, mounting microscopic objects, etc., and does very well for broken glass when it is not to be washed in warm water. The thicker the balsam the stronger, when too thin it may be thickened by gentle evaporation.

To make Paper Water-proof.

Dissolve 8 oz. of alum and 34 oz. of white soap in 4 pints of water; in another vessel dissolve 2 oz. of gum Arabic and 4 oz. of glue in 4 pints of water. Mix the two solutions and make the mixture hot. Immerse the paper in the mixture, and then hang it up to dry or pass it between cylinders.

The alum, soap, glue, and gum form a sort of artificial covering which protects the surface of the paper from the action of water, and to a certain extent from fire. This paper will be very useful for packages which may be exposed to the inclemency of the weather.

New Applications for Gun-cotton.

In order to obtain cheap gun-cotton it may be made of rags instead of new cotton. It is first dissolved in any of its solvents, such as ether and alcohol, and becomes collodion. To this is now added any of the purest animal and vegetable oils, and it forms the new liquid which is to be used as a cement and vehicle. By adding to it gums and resins a cement is formed, which may be rolled out into sheets and stamped in dies into cups, fancy boxes, and various other articles. The oxide of copper imparts a green color to it, and the chloride of lime added renders it uninflammable. The addition of fine flax fibre, or the flocks of wool, renders it strong and flexible. It is stated to be an excellent compound for taking

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