How to Frost Gla.s.s.--Two ounces of spirits of salts, two ounces of oil of vitriol, one ounce of sulphate of copper, one ounce of gum arabic, mixed together and dabbed on with a brush; or this:--Dab your squares regularly over with putty; when dry go over them again--the imitation will be executed. Or this:--Mix Epsom salts with porter and apply it with a brush. Or this one:--Grind and mix white lead in three-fourths of boiled oil, and one-fourth of spirits of turpentine, and, to give the mixture a very drying quality, add sufficient quant.i.ties of burnt white vitriol and sugar of lead. The color must be made exceedingly thin, and put on the panes of gla.s.s with a large painting-brush in as even a manner as possible. When a number of the panes are thus painted take a dry duster, quite new, dab the ends of the bristles on the gla.s.s in quick succession till you give it a uniform appearance; repeat this operation till the work appears very soft, and it will then appear like ground gla.s.s. When the windows require fresh painting, get the old coat off first by using strong pearlash water.
How to Preserve Posts.--Wood can be made to last longer than iron in the ground, if prepared according to the following recipe:--Take boiled linseed oil and stir in pulverized coal to the consistency of paint. Put a coat of this over the timber, and there is not a man that will live to see it rot.
What Diamond Dyes and Paints Are Made of.--Solutions of the aniline colors.
What the Ingredients Are of Soapine and Pearline.--They consist of partly effloresced sal soda mixed with half its weight of soda ash.
Some makers add a little yellow soap, coa.r.s.ely powdered, to disguise the appearance, and others a little carbonate of ammonium or borax.
How Many Thousand Feet of Natural Gas are Equal in Heat-Creating Power to One Ton Anthracite Coal.--About 40,000 cubic feet.
SUSTAINING POWER OF ICE.
The sustaining power of ice at various degrees of thickness is given in the following paragraphs:
At a thickness of two inches, will support a man.
At a thickness of four inches, will support man on horseback.
At a thickness of six inches, will support teams with moderate loads.
At a thickness of eight inches, will support heavy loads.
At a thickness of ten inches, will support 1,000 pounds to the square foot.
THE EXPANSIVE POWER OF WATER.
It is a well known, but not less remarkable fact, that if the tip of an exceedingly small tube be dipped into water, the water will rise spontaneously in the tube throughout its whole length. This may be shown in a variety of ways; for instance, when a piece of sponge, or sugar, or cotton is just allowed to touch water, these substances being all composed of numberless little tubes, draw up the water, and the whole of the piece becomes wet. It is said to _suck up_ or _imbibe_ the moisture. We see the same wonderful action going on in nature in the rising of the sap through the small tubes or pores of the wood, whereby the leaves and upper portions of the plant derive nourishment from the ground.
This strange action is called "capillary," from the resemblance the minute tubes bear to a hair, the Latin of which is _capillus_. It is, moreover, singular that the absorption of the water takes place with great force. If a dry sponge be enclosed tightly in a vessel, it will expand when wetted, with sufficient force to burst it, unless very strong.
London Water Supply.--The quant.i.ty of water consumed in London amounts to about 145,000,000 gallons a day. If this quant.i.ty could be collected together, it would form a lake 700 yards long, 200 wide, and with a uniform depth of 20 feet.
A Protection for Embankments.--Engineers often have considerable trouble with the loose soil of newly-made embankments, so apt to slip or be washed away before they are covered with vegetation. According to a French railway engineer, the best plan is to sow the banks with the double poppy. Several months elapse before gra.s.ses and clovers develop their feeble roots, but the double poppy germinates in a few days, and in a fortnight has grown sufficiently to afford some protection to the slope, while at the end of three or four months the roots, which are ten or twelve inches in length, are found to have interlaced so as to retain the earth far more firmly than those of any gra.s.s or grain. Although the double poppy is an annual, it sows itself after the first year.
A Cheap Concrete.--A kind of concrete made without cement is composed of 8 parts of sand, gravel and pebbles, 1 part of burnt and powdered common earth, 1 part of pulverized clinkers and cinders, and 1-1/2 parts of unslacked hydraulic lime. These materials are thoroughly incorporated while dry into a h.o.m.ogeneous mixture, which is then wetted up and well beaten. The result of this is a hard and solid ma.s.s, which sets almost immediately, becoming exceedingly strong after a few days. It may be made still stronger by the addition of a small proportion--say 1 part--of cement.
Marking Tools.--To mark tools, first coyer the article to be marked with a thin coating of tallow or beeswax, and with a sharp instrument write the name in the tallow. Clear with a feather, fill the letters with nitric acid, let it remain from one to ten minutes, then dip in water and run off, and the marks will be etched into the steel or iron.
How to Prevent Chisel Handles Splitting.--All carpenters know how soon the b.u.t.t-end of chisel handles split when daily exposed to the blow of a mallet or hammer. A remedy suggested by a Brooklyn man consists simply of sawing or cutting off the round end of the handle so as to make it flat, and attaching by a few nails on the top of it two discs of sole leather, so that the end becomes similar to the heel of the boot. The two thicknesses of leather will prevent all further splitting, and if, in the course of time, they expand and overlap the wood of the handle, they are simply trimmed off all around.
The Largest Wheel of Its Kind Ever Made in the World.--The greatest wheel of its kind in the world, a very wonder in mechanism, was built for the Calumet and Hecla Mining Company of Lake Superior, Mich., for the purpose of lifting and discharging the "tailings," a waste from the copper mines, into the lake. Its diameter is 54 feet; weight in active operation, 200 tons. Its extreme dimensions are 54 feet in diameter. Some idea of its enormous capacity can be formed from the fact that it receives and elevates sufficient sand every twenty-four hours to cover an acre of ground a foot deep. It is armed on its outer edge with 432 teeth, 4.71 inches pitch and 18 inches face. The gear segments, eighteen in number, are made of gun iron, and the teeth are machine-cut, epicycloidal in form. It took two of the most perfect machines in the world 100 days and nights to cut the teeth alone, and the finish is as smooth as gla.s.s. The wheel is driven by a pinion of gun iron containing 33 teeth of equal pitch and face and runs at a speed of 6OO feet per minute at the inner edge, where it is equipped with 448 steel buckets that lift the "tailings" as the machine revolves and discharges them into launders that carry them into the lake. The shaft of the wheel is of gun iron, and its journals are 22 inches in diameter by 3 feet 4 inches long. The shaft is made in three sections and is 30 inches in diameter in the center. At a first glance the great wheel looks like an exaggerated bicycle wheel, and it is constructed much on the same principle, with straining rods that run to centers cast on the outer sections of the shaft. The steel buckets on either side of the gear are each 4 feet 5-1/2 inches long and 21 inches deep, and the combined lifting capacity of the 448, running at a speed of 600 feet per minute, will be 3,000,000 gallons of water and 2,000 tons of sand every twenty-four hours. The mammoth wheel is supported on two ma.s.sive adjustable pedestals of cast iron weighing twelve tons each, and its cost at the copper mines before making a single revolution, $100,000.
Strength of Brick Walls.--The question of strength of brick walls is often discussed, and differences of opinion expressed. The following is one of the rules given:--For first-cla.s.s buildings, with good workmanship, the general average should not exceed a greater number of feet in height than three times its thickness of wall in inches, and the length not to exceed double the height, without lateral supports of walls, b.u.t.tresses, etc., as follows for safety:
THICKNESS; SAFE HEIGHT; LENGTH.
8-1/2 inch walls; 25 feet; 50 feet.
13 inch walls; 40 feet; 80 feet.
17 inch walls; 55 feet; 110 feet.
22 inch walls; 66 feet; 130 feet.
26 inch walls; 78 feet; 150 feet.
Where the lengths must exceed these proportions, as in depots, warehouses, etc., the thickness should be increased, or lateral braces inst.i.tuted as frequently as practicable.
Qualities of Building Stone.--The princ.i.p.al qualities of a good building stone are--(1) Strength, (2) hardness, (3) durability, (4) appearance, (5) facility for working. There are also other minor points; but stone possessing one or more of the above qualities, according to the purpose for which it is required, may be regarded as good for that purpose.
Strength of Stone.--Stone should only be subjected to a compressive strain. It is occasionally subject to a cross strain, as in lintels over doors and windows; these are, however, contrary to the true principles of construction, and should not be allowed except a strong relieving arch is turned over them. The strength of stone in compression is about 120 tons per square foot for the weakest stones, and about 750 tons per square foot for the strongest. No stones are, however, subjected to anything like this amount of compressive force; in the largest buildings it does not amount to more than twelve or fourteen tons per square foot.
Hardness of Stone.--This is of more importance than its strength, especially in pavements or steps, where it is subject to great wear; also in plinths and quoins of buildings where it is desired to preserve a good face and sharp arris. The order of strength and hardness of stone is--(1) Basalt, (2) granite, (3) limestone, (4) sandstone. Granite, seinite, and gneiss take the first, place for strength, hardness and durability, but they will not stand a high temperature. "Stones which are of a fine, uniform grain, compact texture and deep color are the strongest; and when the grain, color, and texture are the same, those are the stongest which are the heaviest; but otherwise the strength does not increase with the specific gravity." Great hardness is objectionable when the stone has to be worked with a chisel, owing to the labor required to work it. Hard stones, also, generally wear smooth, and become polished, which makes them unsuitable for some purposes.
Brittleness is a defect which frequently accompanies hardness, particularly in coa.r.s.e-grained stones; it prevents them from being worked to a true surface, and from receiving a smooth edge at the angles. Workmen call those hard stones which can only be sawn into slabs by the grit saw, and those soft which can be separated by a common saw.
Expansion of Stone by Heat.--Rocks are expanded by heat and contracted by cooling. Variation in temperature thus causes some building stones to alternately expand and contract, and this prevents the joints of masonry from remaining close and tight. In the United States with an annual thermometric range of more than 90 deg. Fah., this difficulty led to some experiments on the amount of expansion and contraction in different kinds of building stones. It was found that in fine-grained granite the rate of expansion was .000004825 for every degree Fah., of increment of heat; in white crystalline marble it was .000005668; and in red sandstone .000009532, or about twice as much as in granite. In Western America, where the climate is remarkably dry and clear, the thermometer often gives a range of more than 80 deg. in twenty-four hours. This great difference of temperature produces a strain so great that it causes rocks to crack or peel off in skins or irregular pieces, or in some cases, it disintegrates them into sand. Dr.
Livingstone found in Africa (12 deg. S. lat., 34 deg. E. long.) that surfaces of rock which during the day were heated up to 137 deg.
Fah. cooled so rapidly by radiation at night that unable to stand the strain of contraction, they split and threw off sharp angular fragments from a few ounces to 100 lbs. or 200 lbs. in weight.
According to data obtained from Adie "Trans. Roy. Soc. Edin.," xiii., p. 366, and Totten the expansion of ordinary rocks ranges from about 2.47 to 9.63 millionths for 1 deg. Fah.
BLUNDERS AND ABSURDITIES IN ART.
In looking over some collections of old pictures, it is surprising what extraordinary [Transcriber"s Note: The original text reads "anachornisms"] anachronisms, blunders, and absurdities are often discoverable.
In the gallery of the convent of Jesuits at Lisbon, there is a picture representing Adam in paradise, dressed in blue breeches with silver buckles, and Eve with a striped petticoat. In the distance appears a procession of Capuchin monks bearing the cross.
In a country church in Holland there is a painting representing the sacrifice of Isaac, in which the painter has depicted Abraham with a blunderbus in his hand, ready to shoot his son. A similar edifice in Spain has a picture of the same incident, in which the patriarch is armed with a pistol.
At Windsor there is a painting by Antonio Verrio, in which the artist has introduced the portraits of himself, Sir G.o.dfrey Kneller, and May, the surveyor of the works of that period, all in long periwigs, as spectators of Christ healing the sick.
A painter of Toledo, having to represent the three wise men of the East coming to worship on the nativity of Christ, depicted three Arabian or Indian kings, two of them white and one black, and all of them in the posture of kneeling. The position of the legs of each figure not being very distinct, he inadvertently painted three black feet for the negro king, and three also between the two white kings; and he did not discover his error until the picture was hung up in the cathedral.
In another picture of the Adoration of the Magi, which was in the Houghton Hall collection, the painter, Brughel, had introduced a mult.i.tude of little figures, finished off with true Dutch exact.i.tude, but one was accoutred in boots and spurs, and another was handing in, as a present, a little model of a Dutch ship.
The same collection contained a painting of the stoning of Stephen, the martyr, by Le Soeur, in which the saint was attired in the habit of a Roman Catholic priest at high ma.s.s.
A picture by Rubens, in the Luxembourg, represents the Virgin Mary in council, with two cardinals and the G.o.d Mercury a.s.sisting in her deliberations.
A STOPPAGE OF THE FALLS OF NIAGARA.
The following remarkable account of the stoppage of Niagara Falls, appeared in the _Niagara Mail_ at the time of the occurrence: "That mysterious personage, the oldest inhabitant, has no recollection of so singular an occurrence as took place at the Falls on the 30th of March, 1847. The "six hundred and twenty thousand tons of water each minute" nearly ceased to flow, and dwindled away into the appearance of a mere milldam. The rapids above the falls disappeared, leaving scarcely enough on the American side to turn a grindstone. Ladies and gentlemen rode in carriages one-third of the way across the river towards the Canada sh.o.r.e, over solid rock as smooth as a kitchen floor. The _Iris_ says: "Table Rock, with some two hundred yards more, was left dry; islands and places where the foot of man never dared to tread have been visited, flags placed upon come, and mementoes brought away. This unexpected event is attempted to be accounted for by an acc.u.mulation of ice at the lower extremity of Fort Erie, which formed a sort of dam between Fort Erie and Buffalo.""
WONDERS OF MINUTE WORKMANSHIP.
In the twentieth year of Queen Elizabeth, a blacksmith named Mark Scaliot, made a lock consisting of eleven pieces of iron, steel and bra.s.s, all which, together with a key to it, weighed but one grain of gold. He also made a chain of gold, consisting of forty-three links, and, having fastened this to the before-mentioned lock and key, he put the chain about the neck of a flea, which drew them all with ease. All these together, lock and key, chain and flea, weighed only one grain and a half.
Oswaldus Norhingerus, who was more famous even than Scaliot for his minute contrivances, is said to have made 1,600 dishes of turned ivory, all perfect and complete in every part, yet so small, thin and