—lifted his head to where hung in his reachAll laden with honey, the ruddy-cheeked peach.
—lifted his head to where hung in his reachAll laden with honey, the ruddy-cheeked peach.
—lifted his head to where hung in his reachAll laden with honey, the ruddy-cheeked peach.
—lifted his head to where hung in his reach
All laden with honey, the ruddy-cheeked peach.
Blackberries.—The two fruits already described in this paper are of a comparatively large size, and grow on trees. We now come to the so-called “small fruits,” among which are the blackberry, raspberry, strawberry, currant, and gooseberry. The genusRubus[8]furnishes both the blackberries and the raspberries, thus showing that these two kinds of small fruits are very closely related. There are about one hundred and fifty species of blackberries scattered throughout the world, but of these only two have furnished our gardens with the best cultivated varieties, namely: the high blackberry (R. villosus[9]), growing everywhere in thickets, with a strong prickly stem, six feet high, and the low blackberry, or dewberry (R. canadensis[10]), a long trailing plant, with slightly prickly stems, and small, early ripening fruit.
The cultivation of the blackberry has been retarded to a considerable extent by the excellence of the wild sorts—the people being satisfied with the fruit of the bramble in the fence row. The varieties that now head the list have all been chance seedlings found growing wild, and afterward improved by garden culture. The Lawton was found growing on a roadside in Westchester county, New York, and is often known by the name of its native town, New Rochelle. The Lawton did much to introduce the blackberry to the fruit gardens. The canes winter kill, and the fruit, unless perfectly ripe, is hard and sour at the core. The Kittatinny stands among the first for the size and richness of its fruit. This berry is a little earlier than the New Rochelle. It was found near the Kittatinny mountains, in New Jersey, and bears the peculiar Indian name of the place of its nativity. Mr. Roe, in his “Success with Small Fruits” says of the discoverer of the Kittatinny blackberry: “He has done more for the world than if he had opened a gold mine.”
The Wilson’s early is a third variety, of New Jersey origin, that grows low, with the canes trailing upon the ground. As the name indicates, this is a remarkably early blackberry, and were it not subject to attacks from insects it would be a very superior variety. The Snyder is of western origin, is wonderfully productive and hardy. The small size of the berry is the greatest defect of the Snyder. There are some recent candidates for popular favor, but the four mentioned have been found worthy of a place in the small fruit garden.
The blackberry prefers a rather dry soil, of medium richness. On a moist and very fertile soil the canes grow rank and large and produce very little fruit. The plants need to be set in rows six to eight feet apart each way. It is best to set the plants in autumn, because they start into growth very early in the spring, before there is opportunity for transplanting. Stakes or cheap wire trellises are usually provided for holding up plants. The canes that grow up one season produce fruit the succeeding year, and then die. It is therefore necessary to treat as weeds all shoots that are not needed for the bearing canes the following season. Judicious pruning of the cane while it is growing will produce much branched tops, which are more productive than those that grow to great length, and they are less liable to be injured by frost. Mr. Roe says: “More can be done with the thumb and finger at the right time than with the most savage pruning shears after a year of neglect.” The blackberry produces many suckers, and if these are left to grow for a year or two the whole ground becomes a wilderness that is not productive, and very difficult to subdue.
Strawberries.—It is not an easy task to find the person who dislikes strawberries. They are acceptable to the vast majority, and in almost any form, from the plain berry just picked off the vine to the juicy, red layer in a shortcake, or the heaping saucer with its fragrant contents half floating in sweet cream. The name strawberry probably came from the old Saxonstreawberige, either because of the strawlike stems to the plants, or from the berries being strewn upon the ground. In olden times children strung the berries upon straws and sold them thus, and possibly from this we now have the name for our earliest and finest of small fruits. The name of the strawberry genus isFragaria,[11]the Latin for “sweet smelling.” The cultivated varieties of strawberries represent five species. The most common one, growing wild almost everywhere beingFragaria vesca. In this species the seeds are superficial on the luscious cone. The Virginian strawberry,F. Virginiana, abundant in all parts of the United States, has roundish fruit, with the seeds embedded in deep pits. At the time of the introduction of this species in English gardens the culture of the strawberry took a fresh start. By sowing the seed of the Virginian species new varieties have been produced in large numbers, so that now it is the parent of nine-tenths of all the sorts grown in our gardens. The Hovey, Wilson, monarch, Seth Boyden, Charles Downy, and Sharpless are some of the improved varieties of this species. A new impetus was given to strawberry culture by the introduction of a South American species,F. grandiflora. The fruit is large and sweet, with a peculiar sprightliness that makes the varieties derived from this species highly prized in England and on this continent. Our cold winters and hot summers are too severe extremes for these offsprings of a more tropical species. The triumphe de gand and jucunda are two superb sorts derived from theF. grandiflora.
Some varieties of strawberries have what are known as pistillate flowers; that is, the stamens or male organs are imperfect or wanting. In such cases it is necessary to grow a perfect-flowered (bi-sexual) variety in close proximity, in order to insure fertilization and the formation of fruit. The famous Hovey seedling is a pistillate variety, and there are many others of this character.
One of the leading features of the strawberry plant is to multiplyby means of long, slender branches, called runners. There are, however, three methods of propagating the strawberry, viz.: by the runners, by division of the root, and by seeds. The chief method is by runners. Strawberries need a rich, mellow soil. The plants may be set either in the spring or fall, though the spring is generally preferred by experienced strawberry growers. Plants set in autumn will not come into bearing the next season unless they are pot-grown. These pot-grown plants are obtained by sinking small flower pots in the earth of the strawberry bed, into the contents of which the runners strike root and form plants. The roots of the plants are not disturbed by transplanting, and one whole season is gained. In setting out strawberry plants care needs to be observed that the crown is not buried. The holes should be large, so that the roots may be spread out in all directions. If set in rows two and a half feet apart, and a foot or so distant in the row, a horse and cultivator may be used to advantage in keeping down the weeds. After two or three full crops have been gathered from a bed the rows may be plowed up. Some growers gather only one crop, and reset the land. There are many methods of treatment. In the fall the strawberry bed should be covered with a mulch. The success of many cultivators of the strawberry is due, in great measure, to the protection of their plants in winter.
The insect enemies to the strawberry are numerous, not the least of which is the white grub, the larvæ of the May beetle or “June Bug,” the strawberry worm, the leaf-roller, crown borer, saw fly, and various cut worms. A rust sometimes attacks the plants and almost ruins them.
It is very difficult to indicate what are the best varieties of strawberries. Again referring to the chart in the last issue of the American Pomological Society, we find forty-one varieties there tabulated. Of these the Charles Downing and the Wilson take the lead, being suited to a wide range of climate, soil, and other conditions. The Downing is the type of excellence in flavor and other qualities, while the Wilson is a firm, sour, and very prolific berry well suited for the market garden. Among the other sorts worthy of attention, mentioned alphabetically, are: Crescent, Cumberland, Hovey, Kentucky, Manchester, miner’s prolific, Monarch, Sharpless, and triumphe de gand. A dozen or more new sorts appear each year, some of which may take their places among the time-tested sorts here mentioned. It may be that in a few years all of these old varieties will be superseded by new sorts, and the berries that we now eat with so much relish will seem poor by the contrast. Let the future be as it may, no one should neglect the culture of the kinds we now possess. A person with only a village half acre may grow his own berries of various sorts, and still have room for a few pear, apple, peach, and cherry trees.
Let us close this brief treatment of small fruits at the same place where Mr. Roe began his large, elegant and exhaustive book on the same subject, by quoting the following passage from his “Preliminary Parley:” “Many think of the soil only in connection with the sad words of the burial service, ‘earth to earth, ashes to ashes.’ Let us, while we may, gain more cheerful associations with our kindred dust. For a time it can be earth to strawberry blossoms, ashes to bright red berries, and their color will get into our cheeks, and their rich, sub-acid juices into our insipid lives, constituting a mental, moral and physical alteration that will so change us that we shall believe in evolution, and imagine ourselves fit for a higher state of existence. One may delve in the earth so long as to lose all dread at the thought of sleeping in it at last, and the luscious fruits and bright hued flowers that come out of it, in a way no one can find out, may teach our own resurrection more effectually than do the learned theologians.”
“The liberal use of various fruits as food is conducive to good health. Fruit is not a solid and lasting element like beef and bread, and does not give strength to any great extent. But fruits contain those acids which refresh and give tone to the system during the season when it is most needed. They should never be eaten unless thoroughly ripe, or cooked. Stale fruits, or those that have been plucked some time, are unhealthy in the extreme. The proper time to eat fruit is in the morning and early afternoon. At night it is ‘leaden,’ according to the Spanish, who call fruit ‘golden in the morning and silver at noon.’” These words of general advice fitly introduce our “apples, peaches, strawberries, and blackberries,” for whose use, fresh and uncooked, we would strongly plead.
Ripe Fruit.—Wash and polish apples with a clean towel, and pile in a china fruit basket, with an eye to agreeable variety of color. Of peaches and pears the finest should be selected, handling as little as may be, and pile upon a salver or flat dish, with bits of ice between them, and ornament with peach leaves or fennel sprigs. One of the prettiest dishes of fruit I ever saw upon a dessert table was an open silver basket, wide at the top, heaped with rich red peaches and yellow Bartlett pears, interspersed with feathery bunches of green, which few of those who admired it knew for carrot tops. Wild white clematis wreathed the handle and showed here and there among the fruit, while scarlet and white verbenas nestled amid the green. Send around powdered sugar with the fruit, as many like to dip peaches and pears in it after paring and quartering them.
Never wash strawberries or raspberries that are intended to be eaten as fresh fruit. If they are so gritty as to require this process keep them off the table. You will certainly ruin the flavor beyond repair if you wash them, and as certainly induce instant fermentation and endanger the coats of the eaters’ stomachs, if, after profaning the exquisite delicacy of the fruit to this extent, you complete the evil work by covering them with sugar, and leaving them to leak their lives sourly away for one or two hours. Put them on the table in glass dishes, piling them high and lightly; send around powdered sugar with them and cream, that the guests may help themselves. It is not economical, perhaps, but it is a healthful and pleasant style of serving them—I had almost said the only decent one. “But I don’t know who picked them,” cries Mrs. Fussy.
No, my dear madame! nor do you know who makes the baker’s bread, or confectioner’s cake, creams, jellies, salads, etc. Nor, for that matter, how the flour is manufactured out of which you conjure your dainty biscuits and pies. IknowGod made strawberries. “Doubtless,” says Bishop Butler, “he could have made a better berry, but he never did.” The picker’s light touch can not mar flavor or beauty, nor, were her fingers filthy as a chimney sweep’s, could the delicate fruit suffer from them as from your barbarous baptism.—Marion Harland in “Common Sense in the Household.”
Puddings and Pies.—Apple Dumplings.—Make a crust as for biscuit, or a potato crust, as follows: Three large potatoes boiled and mashed while hot. Add to them two cups of sifted flour and one teaspoonful of salt, and mix thoroughly. Now chop or cut into it one small cup of butter, and mix into a paste with about a teacupful of cold water. Dredge the board thick with flour, and roll out—thick in the middle and thin at the edges. A thick pudding-cloth—the best being made of Canton flannel, used with the nap-side out—should be dipped in hot water and wrung out, dredged evenly and thickly with flour, and laid over a large bowl. Upon the middle of this place the rolled-out crust, fill with apples pared and quartered, eight or ten good-sized ones being enough for this amount ofcrust. Gather the edges of the crust evenly over it. Then gather the cloth up, leaving room for the dumpling to swell, and tying very tightly. In turning out, lift to a dish, press all the water from the ends of the cloth; untie and turn away from the pudding, and lay a hot dish upon it, turning over the pudding into it, and serving at once, as it darkens or falls by standing. In using a boiler, butter well, and fill only two-thirds full, that the mixture may have room to swell. Set it in boiling water, and see that it is kept at the same height, about an inch from the top. Cover the outer kettle, that the steam may be kept in. Peaches pared and halved, or canned ones drained from the syrup, may be used instead of the apples. When canned fruit is used the syrup can be used as a sauce, either cold for cold puddings and blancmanges, or heated and thickened for hot, allowing to a pint of juice a heaping teaspoonful of corn starch, dissolved in a little cold water, and boiling it five minutes. Strawberry or raspberry syrup is especially nice.
Bread and Apple Pudding.—Butter a deep pudding dish and put first a layer of crumbs, then one of any good acid apple, sliced rather thin, and so on until the dish is nearly full. Six or eight apples and a quart of fresh crumbs will fill a two-quart dish. Dissolve a cup of sugar and one teaspoonful of cinnamon in one pint of boiling water and pour into the dish. Let the pudding stand half an hour to swell; then bake until brown—about three-quarters of an hour—and eat with liquid sauce. It can be made with slices of bread and butter instead of crumbs.
Short-Cake.—One quart of flour, one teaspoonful of salt and two of baking powder sifted with the flour, one cup of butter, or half lard and half butter, one large cup of hot milk. Rub the butter into the flour; add the milk and roll out the dough, cutting in small square cakes and baking to a light brown. For a strawberry or peach short-cake have three tin pie-plates buttered; roll the dough to fit them, and bake quickly. Fill either, when done, with a cup of sugar, or with peaches cut fine and sugared, and served hot.
Pies—Apple, Peach, and Berry.—In the first place, don’t make them except very semi-occasionally. Pastry, even when good, is so indigestible that children should never have it, and their elders but seldom. A nice short-cake, filled with stewed fruit, or with fresh berries, mashed and sweetened, is quite as agreeable to eat and far more wholesome. But, as people will both make and eat pie-crust, the best rules known are given. Butter, being more wholesome than lard, should always be used if it can be afforded. A mixture of lard and butter is next best. For a plain pie-crust, take: One quart of flour, one even teacup of lard and one of butter, one teacup of ice water or very cold water, and a teaspoonful of salt. Rub the lard and salt into the flour till it is dry and crumbly, add the ice water and work to a smooth dough. Wash the butter and have it cold and firm as possible, divide it in three parts. Roll out the paste and dot it all over with bits from one part of the butter, sprinkle with flour and roll up. Roll out and repeat until the butter is gone. If the crust can now stand on the ice for half an hour it will be nicer and more flaky. This amount will make three good-sized pies. Enough for the bottom crusts can be taken off after one rolling in of butter, thus making the top crust richer. Lard alone will make a tender, but not a flaky, paste.
For puff paste there is required one pound of flour, three quarters of a pound of butter, one teacupful of ice water, one teaspoonful of salt, one of sugar, and yolk of one egg. Wash the butter, divide into three parts, reserving a bit the size of an egg, and put it on the ice for an hour. Rub the bit of butter, the salt, and sugar, into the flour, and stir in the ice water and egg beaten together. Make into a dough and knead on the moulding-board till glossy and firm—at least ten minutes will be required. Roll out into a sheet ten or twelve inches square. Cut a cake of the ice-cold butter in thin slices, or flatten it very thin with the rolling-pin. Lay it on the paste, sprinkle with flour, and fold over the edges. Press it in somewhat with the rolling-pin and roll out again. Always rollfromyou. Do this again and again until the butter is all used, rolling up the paste after the last cake is in, and then putting it on the ice for an hour or more. Have filling all ready, and let the paste be as nearly ice-cold as possible when it goes into the oven. There are much more elaborate rules, but this insures handsome paste. Make a plainer one for the bottom crusts. Cover puff paste with a damp cloth and it may be kept on the ice a day or two before baking.
Apple Pie.—Line a pie-plate with plain paste. Pare sour apples—greenings are best—quarter and cut in thin slices. Allow one cup of sugar, and quarter of a grated nutmeg mixed with it. Fill the pie-plate heaping full of the sliced apple, sprinkling the sugar between the layers. It will require not less than six good-sized apples. Wet the edges of the pie with cold water, lay on the cover and press down securely, that no juice may escape. Bake three-quarters of an hour, or a little less if the apples are very tender. No pie in which the apples are stewed beforehand can compare with this in flavor. If they are used stew till tender and strain. Sweeten and flavor to taste. Fill the pies and bake half an hour.
Berry Pies.—Have a very deep plate, and either no under crust, save a rim, or a very thin one. Allow a cup of sugar to a quart of fruit, but no spices. Prick the upper crust half a dozen times with a fork, to let out the steam.—Helen Campbell, in “The Easiest Way in Housekeeping and Cooking.”
Apple Méringue Pies.—Stew and sweeten ripe, juicy apples, when you have pared and sliced them. Mash smooth and season with nutmeg. If you like the flavor, stew some lemon peel with the apple, and remove when cold. Fill your crust and bake until just done. Spread over the apple a thick méringue,[1]made by whipping to a stiff froth the whites of three eggs for each pie, sweetening with a tablespoonful of powdered sugar for each egg. Flavor this with rose-water or vanilla; beat until it will stand alone, and cover the pie three-quarters of an inch thick. Set back in the oven until the méringue is well “set.” Should it color too darkly, sift powdered sugar over it when cold. Eat cold. Peach pies are even more delicious made in this manner.
Apple Snowrequires six apples, whites of two eggs and three tablespoonfuls of powdered sugar. Peel and grate the apples into the whites, which must have been whipped to a stiff froth. Beat in the sugar with a few light sweeps of the egg; whip and set in a cold place until wanted. Eat with crackers or cake.—Marion Harland.
Apple Fritters.—Pare some fine apples, and with an apple-corer cut out the core from the center of each; now cut them across in slices, about one-third of an inch thick, having the round opening in the center, dip these in a fritter batter and fry in boiling lard; sprinkle over sugar. Fresh or canned peaches may be used in the same way.—Mrs. Henderson, in “Practical Cooking.”
Putting Up Fruit.—One of the most satisfactory operations which is carried on in the household is the annual putting up of fruit. To be sure, it has its disadvantages, like everything else. The fruit generally gets ripe a week or two earlier than you expect it will, and is brought to you on a day for which you have planned other work; but, after all, there is to the well-regulated mind a rare pleasure in being confronted with a basket of luscious fruit which may be preserved for enjoyment in the winter; and I maintain that the pleasure we receive in midwinter from a dish of peaches, cherries, or plums on the table is not wholly of the senses, but the mind itself enjoys the contrasting picture which inevitably comes before it. Something of the brightness of the long summer days in which it grew and ripened is felt again, and just as chopped pickle in June will suggest a November day when the tomatoes no longer ripen, the cucumbers have gone to seed,and the frost has covered the tangled vines in the garden with a fairy-like network, so red raspberries and pears in December and March minister to other wants than those of the palate. Half the trouble of putting up fruit—the broken cans, the scalded fingers and stained dresses—might be done away with if a woman could enter upon the work in the right spirit. If, instead of complaining in May because the trees are full of blossoms, and exhausting ourselves mentally by putting up the fruit and having it spoil long before it is ripe, we were to refrain from asking if we shall live to eat it or to see it eaten, we should accomplish something really great in preserving our peace of mind as well as our fruit. It is a simple matter also, if entered into with calm cheerfulness, to look over and can the fruit. After the fruit has been carefully examined, set it in a cool room or into the refrigerator, while you examine your cans. It is well to have some new rubber rings on hand, as you may need them; have also a cup of flour paste ready; then if the zinc rings or covers are bent a little, you may still make them air-tight with the paste. If you are at all doubtful about the condition of your cans, use the paste. In a long experience of putting up fruit I have never broken but one can, and that was on account of carelessness in rinsing it in too hot water. I rinse the can in warm water, then set it in a two-quart basin with a little water in it, set it on the stove beside my porcelain kettle, fill the can with boiling fruit, and seal up as quickly as may be. One thing which should be carefully avoided is too much boiling of the fruit after the sugar is put with it. The injury which boiling does is not by any means well understood by many good cooks. Last year I gave up all the care of putting up fruit and pickles to a competent and honest girl; but, by her not knowing that sugar, when boiled, actually changes its nature, and loses much of its sweetness, she used more than twice the quantity which I have used this year, and then the fruit was not so sweet as it ought to be. (When making syrup to eat on hot cakes bear this in mind: after the sugar is dissolved let it come to a boil, but do not boil it.)
Peaches.—If possible, pare and cut up your peaches the afternoon before they are to be canned, and scatter sugar over them. In the morning there will be syrup enough to cook them in. Put this syrup into your porcelain kettle—if you have one, if not, into a bright tin pan; cook a few peaches at a time, try them with a broom-splint; just before they are done add the necessary quantity of sugar. Some housekeepers make a practice of putting one whole peach into a can, to give the almond flavor of the stone to the whole can. You can not, of course, guess at just the number of halves or quarters needed to fill the can; if you have too many pieces, and are afraid of their cooking too much, take them out carefully on a plate and, after cooking others for the next canful, add to them. By cooking a few at a time you can preserve the shape and have much finer results than if you cook a great many at a time.
Quinces and Sweet Apples.—Prepare the quinces and apples as for canning. Steam them in the same way, having about one-third as many quinces as apples. Make a very sweet syrup, as they will keep better with plenty of sugar. These may be canned or kept in a large stone jar.—Emma Whitcomb Babcock, in “Household Hints.”
Preserves.—Preserves are scarcely needed if canning is nicely done. They require much more trouble, and are too rich for ordinary use, a pound of sugar to one of fruit being required. If made at all, the fruit must be very fresh, and the syrup perfectly clear. For syrup allow one teacup of cold water to every pound of sugar, and, as it heats, add to every three or four pounds the white of an egg. Skim very carefully, boiling till no more rises, and it is ready for use. Peaches, pears, green gages, cherries, and crab-apples are all preserved alike. Peel, stone, and halve peaches, and boil only a few pieces at a time till clear. Peel, core, and halve pears. Prick plums and gages several times. Core crab-apples, and cut half the stem from cherries. Cook till tender. Put upwhen coldin small jars, and paste paper over them.
Jams.—Make syrup as directed above. Use raspberries, strawberries, or any small fruit, and boil for half an hour. Put up in small jars or tumblers; lay papers dipped in brandy on the fruit, and paste on covers, or use patent jelly-glasses.
Marmalade.—Quinces make the best; but crab-apples or any sour apple are also good. Poor quinces, unfit for other use, can be washed and cut in small pieces, coring, but not paring them. Allow three-quarters of a pound of sugar and a teacupful of water to a pound of fruit, and boil slowly two hours, stirring, and mashing it fine. Strain through a colander, and put up in glasses or bowls. Peach marmalade is made in the same way.
Fruit Jellies.—Crab-apple, quince, grape, etc., are all made in the same way. Allow a teacup of water to a pound of fruit; boil till very tender; then strain through a cloth, and treat as currant jelly. Cherries will not jelly without gelatine, and grapes are sometimes troublesome. Where gelatine is needed, allow a package to two quarts of juice.
Candied Fruits.—Make a syrup as for preserves, and boil any fruit, prepared as directed, until tender. Let them stand two days in the syrup. Take out; drain carefully; lay them on plates; sift sugar over them, and dry either in the sun or in a moderately warm oven.—Helen Campbell, in “The Easiest Way in Housekeeping and Cooking.”
BY PROF. J. T. EDWARDS, D.D.Director of the Chautauqua School of Experimental Science.
To make theweightfor the winds.—Job xxviii:25.
To make theweightfor the winds.—Job xxviii:25.
One day an old Florentine pump-maker came to Galileo[1]to inquire why he could not make a pump work effectively when it was more than thirty-four feet long. The philosopher could not answer, nor did he solve the problem during his lifetime, but bequeathed it to his pupil, Torricelli.[2]This famous Italian succeeded in partially answering the question in 1643. He performed the following experiment: Taking a glass tube thirty-six inches long and one-fourth of an inch in diameter, closed at one end, he filled it with mercury, and holding his finger over the open end, inverted and placed it in a cup of mercury, then removing his finger, discovered that the quicksilver settled in the tube six inches, leaving a column of the shining metal thirty inches high. He thus demonstrated that air has weight, equal to that of a column of mercury thirty inches in height.
On this supposition it was argued that if the whole height of the air should belessenedthe column would fall. Such was the opinion of Blaise Pascal,[3]who in 1646 requested M. Périer, his brother-in-law, to ascend the Puy de Dome, a summit near Clermont, and repeat the experiment of Torricelli. To his delight, upon reaching the top of the mountain, the column stood three inches lower. Pascal then used a tube fifty feet long, which he filled with water, and found that this liquid could be supported by the air to the height of thirty-four feet. Water is13.6 lighter than mercury, and it will be observed from the foregoing statement, that it was supported 13.6 higher than quicksilver. Here was a full answer to the pump-maker’s query! A column of water, thirty-four feet long and one square inch at the base, weighs fifteen pounds. A column of mercury, thirty inches long and one square inch at the base, weighs fifteen pounds. A column of air the whole height of the atmosphere, one square inch at the base, weighs fifteen pounds.
Any influence, therefore, which varies the weight of the air, will vary the height of a column of quicksilver; and the reverse will of course be true, that any fluctuation in the column of mercury indicates a change in the condition of the atmosphere. Thus, a “falling barometer” predicts foul weather, for it shows that the air is becoming lighter, and will therefore rise, while other air will rush in, with varying speed, to take its place, producing breezes, gales, and possibly tornadoes. The warm air rising may come in contact with a cold stratum above and its moisture be condensed into rain or snow. We shall presently refer to this again.
SHOWING DENSITY OF ATMOSPHERE AT DIFFERENT HEIGHTS.
SHOWING DENSITY OF ATMOSPHERE AT DIFFERENT HEIGHTS.
A quart of air, at ordinary temperature, weighs about eight hundred times less than a quart of water, yet the aggregate pressure of the atmosphere is equal to fifteen pounds on every square inch. A person of average size presents a surface of about two thousand square inches. This would receive a pressure of fifteen tons, a weight more crushing than that of all the shields cast upon the traitorous Tarpeia[4]at the Roman gate.
Herschel calculates that the total weight of the atmosphere is one twelve-hundred-thousandth of that of the earth.
Why does not such enormous pressure destroy life? Because it is counterbalanced by the pressure of air, gases and blood within the body. That this is true may readily be seen in the process of dry-cupping. Bare the arm, take a bit of writing paper an inch and a half long, dip it in alcohol, light, and instantly place in a small wine glass, and at once apply the glass to the soft part of the arm. The flesh under the glass will rise like a pin-cushion, and become red from the pressure of the blood within. Persons going down in diving-bells suffer from the condensation of the air in the bell, while on a high mountain they experience a pressure in the opposite direction, on account of the rarefaction of the atmosphere, the blood often gushing from the nose and ears.
We shall better understand the phenomena of the air by first considering some of its distinctive properties.
MAGDEBURG HEMISPHERES.
MAGDEBURG HEMISPHERES.
This great principle, which applies to all gases as well as to fluids, has many illustrations in nature. The haliotis[5]is held to the rock with a tenacity which sometimes resists the strength of the collector, who would add its iridescent beauty to his cabinet of shells.
Alas for the fisherman’s line whose bait has been swallowed by a skate![6]Quickly descending to the bottom, this broad, flat fish expels the air from beneath it, and defies all effort at capture.
The most complete demonstration of this law is shown by the Magdeburg hemispheres,[7]invented by Otto von Güricke[8]and used by him before Charles V. and his brilliant court. They are still preserved in the ancient city which gave them their name, are twenty-four inches in diameter, and after the air in them had been removed, required twelve horses to separate them.
The pressure of the air varies greatly at different altitudes. At the height of three and one-half miles the column of mercury in a barometer falls to fifteen inches, showing that below that elevation we have as much air as in all the space above.
SHOWING TORRICELLI’S HISTORICAL EXPERIMENT AND THE PRINCIPLE OF THE BAROMETER.
SHOWING TORRICELLI’S HISTORICAL EXPERIMENT AND THE PRINCIPLE OF THE BAROMETER.
The boiling point of liquids is materially influenced by the pressure of the atmosphere. On high mountains potatoes and even eggs can not be cooked by boiling, as the water will all evaporate before it is heated sufficiently to cook them.
Partially fill a glass flask with water, heat it until steam begins to escape, then remove the lamp and insert a stopper, theboiling will cease. Now pour cold water upon the flask, and the water within begins again to boil vigorously. The cold water condenses the steam, creating a partial vacuum, thus relieving the heated water from pressure, and it boils at a lower temperature than 212°. This illustrates the famous culinary paradox that “cold water will make hot water boil.”
The buoyancy of substances in air depends upon the same principle that determines their buoyancy in liquids. It will be proportioned to the amount of air which they displace.
It is correct to say that a balloon rises because the air is heavier, and therefore pushes under the balloon and forces it up; or, that it rises because it displaces more than its own weight of air. Thistle-down may be compressed so that it will fall like shot. The resistance offered by the air to the fall of bodies led men long to hold to the fallacy that the rapidity of the descent of falling bodies was proportioned to their weight. This error was at length exploded by Galileo in his interesting experiment on the leaning tower of Pisa.[9]In a vacuum, a cannon ball and a feather fall in the same time.
AIR PUMP.
AIR PUMP.
The statement that air can be expanded involves the counter-truth that it may be compressed.
Mariotte[10]announces the law as follows: Doubling the pressure upon a given amount of gas will halve the space it occupies, and double its expansive energy. The application of this principle in one form gives us the air-gun.[11]If the air in a gun-barrel forty inches long were compressed into the space of half an inch it would press with eighty times its previous force, or with a power equal to twelve hundred pounds to the square inch. Compressed air is often used as a power in mines and excavations, and its advantages are many; it was so employed in the Hoosac tunnel. Though the engine that compressed the air was three miles away, the loss from friction was very slight, and the air, having performed its work in driving the drill, was then liberated to purify the atmosphere of the tunnel and expel noxious gases which accumulated from continuous blasting. The apparatus for compressing air is called a condenser. It consists essentially of a cylinder and piston, with a valve in the bottom of each, opening downward. A precisely opposite arrangement of valves is found in the air-pump, a machine for exhausting air from a given space, usually a receiver. As the piston is raised in removing the air, the valve closes, and the air is thus forced out of the cylinder; the air in the receiver then expands, opens the valve at the bottom of the cylinder, and rises into it; as the piston descends its valve is opened; rising, it again removes the cylinder full of air; the air in the receiver again expands, opens the lower valve, and so continues, until the air in the vessel becomes too much rarefied to lift the delicate valve and make its escape. The vacuum thus produced is by no means so perfect as the “Torricellian vacuum,”[12]the name given to the unoccupied space above the column of mercury in a barometer.
Various substances may be placed in a receiver to show the expansive tendency of air. A piece of wood immersed in a jar of water will throw off thousands of little bubbles. A shriveled apple will become round and plump. The air in an empty rubber bag will often expand so as to fill the receiver. Air in a thin glass vessel, tightly corked, will expand so as to burst the vessel into fragments.
The following simple but useful piece of apparatus can easily be made: Take a pint bottle with a nicely fitted cork, through the cork insert a small glass tube so as to be perfectly air-tight (melted sealing wax is convenient for making tubes or glass tight;) a perforatedrubberstopper is better. Let the end of the tube inserted be drawn out in the flame of an alcohol lamp (this is not essential, but will make the experiments more interesting), suck the air from the bottle, close the end of the tube at once with the finger and place it in a glass of water, and a miniature fountain, in vacuo, will be revealed. After performing this pretty experiment remove the tube and reinsert it with the larger end down, having filled the bottle two-thirds full of water. With the lips force a quantity of air into the bottle, upon removing the mouth the water will rise in the tube and fall in a fine spray from the small aperture at the top. This last experiment is particularly interesting, as it is a perfect illustration of a flowing oil well. Closely allied to the expansibility of air is its
Or tendency to regain its former volume after being compressed. Many a school-boy has observed this property, while manipulating his fascinating popgun. When he places his finger over the open end of the piece of elder, utilized as a gun, and suddenly pushes down the piston upon the wad, he notices that it quickly flies back. An inflated bladder thrown upon the floor bounds like a rubber ball; force pumps in our houses act upon this principle. The air in the chamber of the pump is first compressed by the entrance of the water; it reacts like a spring, and forces the water through the pipes to the rooms above.
EXPANDING RUBBER BAG IN AN EXHAUSTED RECEIVER.
EXPANDING RUBBER BAG IN AN EXHAUSTED RECEIVER.
The hydraulic ram is another application of the same principle. Perhaps the reader may know some place where this apparatus can be used. Let us briefly describe the conditions of its operation. Near your house, at a lower elevation, may be a beautiful spring, so situated that, within the distance of about seventy feet, a fall of from five to ten feet can be obtained. Now run a large pipe from the spring to the spot where the ram is to be placed, below the level of the spring. The ram is a pear-shaped, cast iron cylinder, open at the small end, at which point a valve is placed, opening upward. The pipe coming from the spring is screwed into the bottom of the ram below this valve, in such a manner as to conduct the water past the valve, and out through an opening beyond. At this point, however, is placed a metallic valve, against which, as the water escapes, it continues to crowd. Presently the rushing stream obtains sufficient momentum to close this valve, and thus prevent for a moment its further escape. The accumulated force of the water then raises the valve in the bottom of the ram and it rises into the chamber, which is partially filled with air. This air is compressed, but on account of its elasticity at once reacts upon the water and forces it throughanother pipe to the required height. Only about one-eighth of the water is sent through the last pipe, as seven-eighths of it is required to force the remainder to the desired elevation. I have a great respect for this useful apparatus, the invention of the elder Montgolfier.[13]I know of one hydraulic ram which for fifteen years has raised, through a pipe twenty-two hundred feet long, to an elevation of seventy-five feet, an average of twenty-four barrels of water daily. Its total cost for repairs has not exceeded twenty-five dollars, and yet it has done every day the work of four men. If men had been hired to do this labor at $1.50 per day each, their wages would have amounted to the snug sum of $32,850.
A FOUNTAIN MADE BY COMPRESSING AIR IN A BOTTLE.
A FOUNTAIN MADE BY COMPRESSING AIR IN A BOTTLE.
Atmospheric pressure is employed in many of our cities to convey packages from one part of a building to another, and to even greater distances. This “Pneumatic Dispatch”[14]system, as it is called, was first tried successfully in Paris, in 1865. A company was then established, which now claims to send eight hundred and thirty packages daily. In our own country this curious appliance may be seen in operation at the United States Express office in New York City, in the mammoth establishment of Mr. Wanamaker, in Philadelphia, and doubtless in many other places. For many years attempts have been made to propel cars by compressed air, but as yet the expense of such a plan greatly exceeds that of steam.
Among the most gracious and beautiful offices performed by the atmosphere is the reflection and refraction of light. The blue dome of the sky, the magnificent coloring of the clouds, and all the delicate and ever varying tints of the morning and evening twilight are due to its influence. Without the air we should be in complete darkness until the sun rose, a fiery ball, above the horizon. All day long the only light we should receive would come directly from the sun, or be reflected from objects on the earth. At sunset, darkness would instantly be spread over us like a pall. No gentle gradations of light and deepening shade would usher in and close the day.
All must have observed during the past year the remarkable appearance of the western sky after the sun had set. Cities were more than once supposed to be burning, reflecting their lurid blaze upon the clouds. The cause of this is still a matter of dispute, but is generally attributed to the presence of star dust, or some minute mineral matter suspended in the higher atmosphere.
It will be remembered that color is not an inherent property of a substance, but depends upon what portion of the light rays it absorbs. Snow is white, as it absorbs none of the prismatic colors, but reflects them all to the eye. Whatever, then, varies the absorbing or reflecting power of an object varies its tints. Thus, objects seen on the horizon are red, because the dense atmosphere has turned aside the violet, indigo, blue, green, yellow and orange, and only the red color reaches the eye.
Observe that the initial letter of the prismatic colors taken in their order make the word “vibgyor.”
Again, were there no atmosphere, there could be no
The moon is destitute of these, or at least that half of it which is always turned toward us. The most powerful telescopes can detect there the presence of neither atmosphere nor cloud.
A most remarkable proof of divine wisdom can be seen in the nice adjustment by which the pressure of the air prevents undue evaporation from the lakes and seas, and at the same time furnishes the medium by which moisture is conveyed to the remotest parts of the earth. The fact that water, in the form of mist or clouds, should float, and not fall in a substance many times lighter than itself, is one of the most wonderful of nature’s phenomena. When shot are dropped into water, we expect that they will sink; yet lead is but eleven times heavier than water, while water is eight hundred times heavier than air.
The following seems to be the most satisfactory explanation of the matter: It is a well known fact that the air has the power to absorb and hold, in an invisible form, a certain amount of moisture. The quantity which it can contain depends upon its temperature. If the air is cooled, it parts with a portion; thus if the grass radiates its heat, dew is deposited upon it; if it is very cold, the frost covers it with sparkling crystals. It is thought that when cooling from any cause takes place in higher altitudes, the atmospheric moisture changes from the invisible to the visible form, and assumes the physical condition of spheroids or vesicles, minute bubbles of water in point of fact, each bubble filled with air. These bubbles, heated by the sun’s rays, would become lighter than the medium in which they float, for the same reason that soap bubbles float while they are warm. In this condition they are drifted along by currents until they reach a colder stratum of air, when they are condensed and fall as rain. If cooled sufficiently, snow would be formed.
Cloud forms are four in number, cirrus, cumulus, nimbus, and stratus, all of which may sometimes be seen at once, in the sky of a summer’s day. At times they float above the loftiest mountains. Gay-Lussac,[15]rising in his balloon to an elevation of 21,600 feet, perceived clouds drifting far above him.