Chapter 1

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SCIENTIFIC AMERICAN SUPPLEMENT NO. 443.

NEW YORK, JUNE 28, 1884.

Scientific American Supplement. Vol. XVII., No. 443.

Scientific American established 1845

Scientific American Supplement, $5 a year.

Scientific American and Supplement, $7 a year.

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TABLE OF CONTENTS.

I. CHEMISTRY AND METALLURGY.--Beeswax and its Adulterations. --Chemical ingredients.--Detection of adulterations. 7064

Phenol in the Stem, Leaves, and Cones of Pinus Sylvestris. --A discovery bearing on the flora of the Carboniferous epoch and the formation of petroleum. 7065

The School of Physics and Chemistry of Paris.--With engraving of laboratory. 7065

Some Relations of Heat to Voltaic and Thermo Electric Action of Metals in Electrolysis.--By G. GORE. 7070

II. ENGINEERING, MECHANICS, ETC.--Air Refrigerating Machine.--5 figures. 7071

A Gas Radiator and Heater. 7071

Concrete Water Pipes. 7071

The Sellers Standard System of Screw Threads. Nuts, and Bolt Heads.--A table. 7072

An English Railway Ferry Boat.--3 figures. 7072

The Problem of Flight and the Flying Machine. 7072

III. TECHNICAL.--Concrete Buildings for Farms.--How to construct them. 7063

What Causes Paint to Blister and Peel?--How to prevent it. 7063

Olive Oil.--Difficulties encountered in raising an olive crop.--Process of making Oil. 7064

IV. ELECTRICITY. ETC.--Telephony and Telegraphy on the Same Wires Simultaneously.--4 figures. 7067

The Electric Marigraph.--An apparatus for measuring the height of the tide.--With engravings and diagrams showing the Siemens and Halske marigraph and the operation of the same. 7068

Delune & Co.'s System of Laying Underground Cables.--2 figures. 7069

Electricity Applied to Horseshoeing.--Quieting an unruly animal.--3 engravings. 7069

Esteve's Automatic Pile.--1 figure. 7070

Woodward's Diffusion Motor. 7070

V. ASTRONOMY.--Lunar Heat.--Its reflected and obscure heat.--Trifling influence of the moon upon wind and weather.--By Prof. C.A. YOUNG. 7073

VI. NATURAL HISTORY.--The Long-haired Pointer "Mylord." --With engraving. 7073

VII. HORTICULTURE, ETC.--Apple Tree Borers.--Protection against the same. 7074

Keffel's Germinating Apparatus.--With engraving. 7074

Millet.--Its Cultivation. 7074

VIII. MISCELLANEOUS.--Puerta del Sol, Madrid, Spain.--With engraving. 7063

Dust-free Spaces.--A lecture delivered by Dr. OLIVER J. LODGE before the Royal Dublin Society. 7067

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PUERTA DEL SOL, MADRID.

Puerta del Sol, or Gate of the Sun, Madrid, is the most famous and favorite public square in the Spanish city of Madrid. It was the eastern portal of the old city. From this square radiate several of the finest streets, such as Alcala, one of the handsomest thoroughfares in the world, Mayor, Martera, Carretas, Geronimo. In our engraving the post office is seen on the right. Large and splendid buildings adorn the other sides, which embrace hotels, cafes, reading rooms, elegant stores, etc. From this square the street railway lines traverse the city in all directions. The population of the city is about 400,000. It contains many magnificent buildings. Our engraving is from _Illustrirte Zeitung_.

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CONCRETE BUILDINGS FOR FARMS.

Buildings made of concrete have never received the attention in this country that they deserve. They have the merit of being durable and fire-proof, and of not being liable to be blown down by violent winds. It is very easy to erect them in places where sand and gravel are near at hand and lime is comparatively cheap. Experiments made in England show that coal screenings may be employed to good advantage in the place of sand and gravel. Mr. Samuel Preston, of Mount Carroll, Ill., has a dwelling and several other buildings made of concrete and erected by himself. They were put up in 1851, and are in excellent condition. In _The Farmers' Review_ he gives the following directions for building concrete walls:

First, secure a good stone foundation, the bottom below frost, the top about one foot above ground. Near the top of the foundation bed in 2×4 scantling edgewise transversely with the walls, at such distances apart as the length of the planks that form the boxes to hold the concrete may require, the ends of the scantling to run six inches beyond the outside and inside of the wall. Now take 2×6 studding, one foot longer than the height of the concrete walls are to be, bolt in an upright position in pairs to each end of the 2×4 scantling, and, if a foot wall is to be built, sixteen inches apart, as the box plank will take up four inches. To hold the studding together at the top, take pieces of 2×6 lumber, make two mortises in each piece large enough to slip easily up and down on the studding, forming a tie. Make one mortise long enough to insert a key, so that the studding can be opened at the top when the box plank are to be raised. When the box plank are in position, nail cleats with a hole in each of them on each side of the studding, and corresponding holes in the studding, into which insert a pin to hold the plank to the studding. Bore holes along up in the studding, to hold the boxes when raised.

To make the walls hollow, and I would do it in a building for any purpose, use inch boards the same width of the box plank, one side planed; put the two rough sides together with shingles between, nailing them together with six-penny nails; place them in the middle of the wall, the thin end of the shingle down. That gives them a bevel and can be easily raised with the boxes. To tie the wall together, at every third course place strips of boards a little shorter than the thickness of the wall; cut notches in each so that the concrete will fill in, holding all fast. The side walls being up, place two inch planks on top of the wall upon which to rest the upper joists, put on joist and rafters, remove the box plank, take inch boards for boxes, cut to fit between joists and rafters, and fill with concrete to upper side of rafters, which makes walls that will keep out cold and damp, all kinds of vermin, and a roof which nothing but a cyclone can remove. In making door and window frames, make the jambs two inches narrower than the thickness of the walls, nailing on temporary two inch strips.

Make the mortar bed large enough to hold the material for one course; put in unslaked quicklime in proportion to 1 to 20 or 30 of other material; throw into it plenty of water, and don't have that antediluvian idea that you can drown it; put in clean sand and gravel, broken stone, making it thin enough, so that when it is put into boxes the thinner portion will run in, filling all interstices, forming a solid mass. A brick trowel is necessary to work it down alongside the boxing plank. One of the best and easiest things to carry the concrete to the boxes is a railroad wheelbarrow, scooping it in with a scoop shovel. Two courses a week is about as fast as it will be safe to lay up the walls.

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The _Medical Summary_ recommends the external use of buttermilk to ladies who are exposed to tan or freckles.

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WHAT CAUSES PAINT TO BLISTER AND PEEL?

HOW TO PREVENT IT.

This subject has been treated by many, but out of the numerous ideas that have been brought to bear upon it, the writers have failed to elucidate the question fully, probably owing to the fact that in most parts they were themselves dubious as to the real cause. Last year W.S. gave a lengthy description in the _Building News_, in which he classified blistering and peeling of paint into one of blistering only. He stated in the beginning of his treatise the following:

"The subject of blistering of paint has from time to time engrossed the attention of practical men; but so far as we can follow it in the literature pertaining to the building trade, its cause has never been clearly laid down, and hence it is a detail enshrouded in mystery."

W.S. dwells mostly, in his following explanations on blistering paints, on steam raised in damp wood. Also an English painter, according to the _Painters' Journal_, lately reiterates the same theory, and gives sundry reasons how water will get into wood through paint, but is oblivious that the channels which lead water into wood are open to let it out again. He lays great stress on boiled oil holding water in suspense to cause blistering, which is merely a conjecture. Water boils at 212° F. and linseed oil at 600° F., consequently no water can possibly remain after boiling, and a drop of water put into boiling oil would cause an explosion too dangerous to be encountered.

It will be shown herewith that boiled oil, though in general use, is unfit for durable painting, that it is the cause of most of the troubles painters have to contend with, and that raw linseed oil seasoned by age is the only source to bind pigments for durable painting; but how to procure it is another trouble to overcome, as all our American raw linseed oil has been heated by the manufacturers, to qualify it for quick drying and an early market, thereby impairing its quality. After linseed oil has been boiled, it becomes a poor varnish; it remains soft and pliable when used in paint, giving way to air pressure from the wood in hot weather, forming blisters. Turpentine causes no blistering; it evaporates upon being exposed, and leaves the paint in a porous condition for the gas in the wood to escape; but all painters agree that blistering is caused by gas, and on investigation we find two main sources from which gas is generated to blister paint--one from the wood, the other from the ingredients of the paint. The first named source of gas is started in hot weather by expansion of air confined in painted wood, which presses against the paint and raises blisters when the paint is too soft to resist. Tough, well-cemented paint resists the pressure and keeps the air back. These blisters mostly subside as soon as the air cools and returns to the pores, but subsequently peel off.

W.S. and others assert that damp in painted wood turns into steam when exposed to sun heat, forming blisters, which cannot be possible when we know that water does not take a gaseous form (steam) at less than 212° F. They have very likely been deluded by the known way of distilling water with the aid of sunshine without concentrating the rays of the sun, based upon the solubility of water in air, viz.: Air holds more water in solution (or suspension) in a warmer than in a cooler degree of temperature; by means of a simple apparatus sun-heated air is guided over sun-heated water, when the air saturated with water is conducted into a cooler, to give up its water again. But water has an influence toward hastening to blister paint; it holds the unhardened woodsap in solution, forming a slight solvent of the oil, thereby loosening the paint from the wood, favoring blistering and peeling. There is a certain kind of blister which appears in certain spots or places only, and nowhere else, puzzling many painters. The explanation of this is the same as before--soft paint at these spots, caused by accident or sluggish workmen having saturated the wood with coal oil, wax, tar, grease, or any other paint-softening material before the wood was painted, which reacts on the paint to give way to air pressure, forming blisters.

The second cause of paint blistering from the ingredients of the paint happens between any layer of paint or varnish on wood, iron, stone, or any other substance. Its origin is the gaseous formation of volatile oils during the heated season, of which the lighter coal oils play the most conspicuous part; they being less valuable than all other volatile oils, are used in low priced japan driers and varnishes. These volatile oils take a gaseous form at different temperatures, lie partly dormant until the thermometer hovers at 90° F. in the shade, when they develop into gas, forming blisters in airtight paint, or escape unnoticed in porous paint. This is the reason why coal-tar paint is so liable to blister in hot weather; an elastic, soft coal-tar covering holds part of its volatile oil confined until heated to generate into gas; a few drops only of such oil is sufficient to spoil the best painted work, and worse, when it has been applied in priming, it settles into the pores of the wood, needing often from two to three repetitions of scraping and repainting before the evil is overcome. Now, inasmuch as soft drying paint is unfit to answer the purpose, it is equally as bad when paint too hard or brittle has been used, that does not expand and contract in harmony with the painted article, causing the paint to crack and peel off, which is always the case when either oil or varnish has been too sparingly and turpentine too freely used. Intense cold favors the action, when all paints become very brittle, a fact much to be seen on low-priced vehicles in winter time. Damp in wood will also hasten it, as stated in blistering, the woodsap undermining the paint.

To avoid peeling and blistering, the paint should be mixed with raw linseed oil in such proportions that it neither becomes too brittle nor too soft when dry. Priming paint with nearly all oil and hardly any pigment is the foundation of many evils in painting; it leaves too much free oil in the paint, forming a soft undercoat. For durable painting, paint should be mixed with as much of a base pigment as it can possibly be spread with a brush, giving a thin coat and forming a chemical combination called soap. To avoid an excess of oil, the following coats need turpentine to insure the same proportion of oil and pigment. As proof of this, prime a piece of wood and a piece of iron with the same paint; when the wood takes up part of the oil from the paint and leaves the rest in proportion to harden well, where at the same time the paint on iron remains soft. To be more lucid, it need be explained, linseed oil boiled has lost its oleic acid and glycerine ether, which form with the bases of pigments the insoluble soap, as well as its albumen, which in boiling is thrown out. It coagulates at 160° F. heat; each is needed to better withstand the action of wind and weather, preventing the dust from attaching itself to a painted surface, a channel for ammonia in damp weather to dissolve and wash off the paint. In later years linseed oil has been extracted from linseed meal by the aid of naphtha and percolation, the product of a very clear, quick drying oil, but lacking in its binding quality, no doubt caused by the naphtha dissolving the fatty matter only, leaving the glycerine and albumen in the meal.

All pigments of paint group according to their affinity to raw linseed oil into three classes. First, those that form chemical combinations, called soap. This kind is the most durable, is used for priming purposes, and consists of lead, zinc, and iron bases, of which red lead takes up the most oil; next, white lead, the pure carbonate Dutch process made, following with zinc white and iron carbonates, as iron ore paint, Turkey umber, yellow ocher; also faintly the chromates of lead--chrome-green and chrome-yellow, finishing with the poorest of all, modern white lead, made by the wet or vinegar process. The second class being neutrals have no chemical affinity to linseed oil; they need a large quantity of drier to harden the paint, and include all blacks, vermilion, Prussian, Paris, and Chinese blue, also terra di Sienna, Vandyke brown, Paris green, verdigris, ultramarine, genuine carmine, and madderlake. The last seven are, on account of their transparency, better adapted for varnish mixtures--glazing. The third class of pigments act destructively to linseed oil; they having an acid base (mostly tin salt, hydrochloride of tin, and redwood dye), form with the gelatinous matter of the oil a jelly that will neither work well under the brush nor harden sufficiently, and can be used in varnish for glazing only; they are not permanent in color, and among the most troublesome are the lower grades of so-called carmines, madderlakes, rose pinks, etc., which contain more or less acidous dyes, forming a soft paint with linseed oil that once dry on a job can be twisted or peeled off like the skin of a ripe peach. All these combinations of paint have to be closely observed by the painter to insure his success.

Twenty-five years ago a house needed to be painted outside but once in from five to seven years; it looked well all the time, as no dust settled in the paint to make it unsightly. Painters then used the Dutch-process-made white-lead, a base and raw linseed oil, a fat acid, which formed the insoluble soap. They also put turpentine in the following coats, to keep up the proportions of oil and pigment. All held out well against wind and weather. Now they use the wet-process-made white lead, neutralized by vinegar, with oil neutralized by boiling, from the first to the last coat, and--fail in making their work permanent.

W.S., in the _Building News_, relates an unaccountable mysterious blistering in a leaky house, where the rainwater came from above on a painted wood wall, blistering the paint in streaks and filled at the lower ends with water, which no doubt was caused by the water soaking the wood at the upper ends where there was no paint, and following it down through the fibers, pushed and peeled off the soft, inadhesive paint. Green, sappy, and resinous wood is unfit for durable painting, and to avoid blistering and peeling wood should be well seasoned and primed with all raw linseed oil, some drier, to insure a moderately slow drying, and as much of a base pigment as the painter can possibly spread (much drier takes up too much oil acid, needed for the pigment base to combine with), which insures a tough paint that never fails to stand against blistering or peeling, as well as wind, weather, and ammonia.

The coach, car, and house painter can materially improve his painting where his needs lie by first oiling the wood with raw oil, then smoothing the surface down with lump pumicestone, washing it with a mixture of japan drier or, better yet, gold sizing and turpentine, wiping dry, and following it up with a coat of white lead, oil, and turpentine. The explanation is: the raw oil penetrates the wood and raises the wood fibers on the surface to be rubbed down with pumicestone, insuring the best surface for the following painting: to harden the oil in the wood it receives a coat of japan drier, which follows into the pores and there forms a tough, resinous matter, resisting any air pressure that might arise from within, and at the same time reacts on the first coat of lead as a drier. This mode insures the smoothest and toughest foundation for the following painting, and may be exposed to the hottest July sun without fear of either blistering or peeling.

LOUIS MATERN.

Bloomington, Ill.

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OLIVE OIL.

The following particulars with regard to the production of olive oil in Tuscany have been furnished to Mr. Consul Inglis by one of the principal exporters in Leghorn:

The olive oil produced in Tuscany from the first pressing of the fruit is intended for consumption as an article of food. Hence, great attention is paid both to the culture of the olive tree and the process of making oil.

The olive crop is subject to many vicissitudes, and is an uncertain one. It may be taken as a rule that a good crop does not occur more frequently than once in three years. A prolonged drought in summer may cause the greater part of the small fruit to fall off the trees. A warm and wet autumn will subject the fruit to the ravages of a maggot or worm, which eats its way into it. Fruit thus injured falls to the ground prematurely, and the oil made from it is of very bad quality, being nauseous in taste and somewhat thick and viscous. Frost following immediately on a fall of snow or sleet, when the trees are still wet, will irretrievably damage the fruit, causing it to shrivel up and greatly diminishing the yield of oil, while the oil itself has a dark color, and loses its delicate flavor.

The olive tree in Tuscany generally blossoms in April. By November the fruit has attained its full size, though not full maturity, and the olive harvest generally commences then. The fruit, generally speaking, is gathered as it falls to the ground, either from ripeness or in windy weather. In some districts, however, and when the crop is short, the practice is to strip the fruit from the trees early in the season. When there is a full crop the harvest lasts many months, and may not be finished till the end of May, as the fruit does not all ripen simultaneously.

Oil made early in the season has a deeper color, and is distinguished by a fruity flavor, with a certain degree of pungency; while as the season advances it becomes lighter in color, thinner in body, and milder and sweeter in taste. Oil made toward the close of the harvest in April or May from extremely ripe fruit is of a very pale straw color, mild and sweet to the taste, though sometimes, if the fruit has remained too long on the trees, it may be slightly rancid. Oil very light in color is much prized in certain countries, notably France, and hence, if it also possesses good quality, commands a higher price in the Tuscan markets.

The fruit of the olive tree varies just as much in quality as does the grape, according to the species of the tree itself, the nature of the soil, exposure, and climate of the locality where it grows. Some varieties of the olive tree largely grown, because thought to be better suited to the special conditions of some districts, yield a fruit which imparts a bitter taste to the oil made from it; such oil, even when otherwise perfect, ranks as a second rate quality.

The highest quality of oil can only be obtained when the fruit is perfectly and uniformly sound, well ripened, gathered as soon as it has dropped from the trees, and crushed immediately with great attention. Should the fruit remain any time on the ground, particularly during wet weather, it deteriorates fast and gets an earthy taste; while if allowed to remain an undue length of time in the garners it heats, begins to decompose, and will yield only bad oil.

The process of making oil is as follows: The fruit is crushed in a stone mill, generally moved by water power; the pulp is then put into bags made of fiber, and a certain number of these bags, piled one upon another, are placed in a press, most frequently worked by hand; when pressure is applied, the oil flows down into a channel by which it is conveyed to a receptacle or tank.