Leyden jar

“ The larger the Leyden jar, the shorter the spark, and vice versâ. By the employment of a nicely-made screw and inch-scale, the distance between the discharging points connected with a Leyden jar can be accurately determined; and Mr. Hearder states that supposing a Leyden jar has one square foot of charging surface, it will give a spark of one inch in length, but if a smaller jar is used, with only half a square foot of charging surface, the spark would be about one inch and a quarter in length. (Fig. 228.) ”

“ At the same time an instantaneous current was observed in the conductor between the pile and the jar, which had all the properties of an ordinary current. Now it is evident that the subaqueous wire with its insulating covering may be assimilated exactly to an immense Leyden-jar. The glass of the jar represents the gutta-percha; the internal coating is the surface of the copper wire; the external coating is the surrounding metallic envelope and water. ”

“ This mutual attraction enables us to charge the two pieces of foil much more strongly than if they were each on a separate pane, and this is the secret of the working of the Leyden jar. If the knob of the jar is held to the positive ball of a Wimshurst, the inside coating receives a positive charge, which acts inductively on the outside coating, attracting a negative charge to the inner face of the latter, and repelling a positive charge to its outer face, and thence away through the hand. The electricity is entirely confined to the sides of the jar, the interior having no charge whatever. ”

“ The most familiar instance of induction is probably well known to the reader in the Leyden jar, Fig. 255, which is simply a wide-mouthed bottle of thin glass, covered internally and externally with tin-foil to within a few inches of the neck. The inner coating communicates by means of a rod and chain with a brass knob. Such a jar admits of the accumulation of a larger quantity of electricity than the conductor of a machine will retain. A very few turns of the machine will 490suffice usually to charge the conductor to the fullest extent ”

“ Philip Syng mounted one of the tubes upon a crank and employed a cannon-ball as a prime conductor, thus obtaining the same result without much tedious rubbing of the tube.
The summer of 1747 was devoted to preparing the province for defence. But during the following winter the Philadelphians resumed their experiments. The wondrous Leyden jar was the object of Franklin's constant observation. His method of work is well shown in his own account of an experiment during this winter. The jar used was Maschenbroeck's original device of a bottle of water with a wire running through the cork. ”

“ In the former method, now commonly known as charging in cascade, the jars are insulated and the outside coating of one jar is connected to the inside coating of the next and so on for a whole series, the inside coating of the first jar and the outside coating of the last jar being the terminals of the condenser. For charging in parallel a number of jars are collected in a box, and all the outside coatings are connected together metallically and all the inside coatings brought to one common terminal. This arrangement is commonly called a battery of Leyden jars. ”

“ An eight-inch electrophorus ought to give an inch spark if properly made and charged. To charge the Leyden jar, all you have to do is to hold the knob near the cover and take from fifty to a hundred sparks. You should have the electrophorus raised so as not to have to lift the cover too high each time, and you should hold the jar by its bottom, thus giving the necessary connection with the earth.
Fig. 1.
The cylinder machine (Fig. 1) is a much more complicated affair. It consists of a stand A ”

“ I. p. 313; “Lond. and Edin. Phil. Mag.,” Vol. XXXII. p. 165) , and he not long after constructed a very singular apparatus to a Leyden jar consisting of a wire 140 miles long, perfectly insulated with gutta-percha, one end of which communicated with an insulated pile of 360 elements of zinc and copper charged with acidulated water, as described in the “Britannica.” The results of his inquiries concerning the Leyden jar charge of buried electric conducting wires were, according to Whitehouse’s pamphlet on the Atl. Tel. (p. 5) communicated to the Roy. Inst. ”

“ He looked by no means a wicked or designing old man. I was glad of that. He opened the chest, took out my box, and placed it carefully on the table in the moonlight. Then he went to a part of the room I could not see, and I heard a sound of water being poured into a metal basin, and he came into sight again, wiping his hands on a white towel. He opened the box, took out a little silver spoon and one of the jars, took off [35] the lid and dipped the spoon in the jar and touched first his right eye and then his left with it. ”

“ Sham Voyez "Fair Hebe" jugs, made for foolish collectors, are frequently to be seen and avoided.
Leeds ware has engaged the attention of the imitator. Some of the ware is made in Germany and is unmarked. But other modern productions exist stamped "Leeds Pottery," and are imitations of the old Leeds patterns. There is a tobacco jar in pewter having a shield with the Leeds coat-of-arms, [64] and raised medallions of a ship and of the patron saint of the woolcombers. This jar has been of late years copied in cream ware, and with its lid with twisted handle it has passed as "genuine old Leeds." ”

“ Adelaide then filled the sterilized jar with the fruit, inserted a silver knife between the grapes and the jar to let the air bubbles rise to the top and break, fitted on a new rubber smoothly, sealed the jar quickly and stood it upside down out of the way of any draft. In the morning she inspected the jar carefully to be sure that it did not leak, wiped off all stickiness with a damp cloth, pasted on the label and stored the jar away in the preserve closet. ”

“ Tops for Economy jars must be purchased new each year.
Small necked bottles can be used for holding fruit juices. Large mouthed bottles can be used for jams, marmalades and jellies.
Tests for Jars and Rubbers
Jars should be tested before they are used. Some of the important tests are here given:
Glass-top Jars.—Fit top to jar. If top rocks when tapped it should not be used on that jar. The top bail should not be too tight nor too loose. If either too tight or too loose the bail should be taken off and bent until it goes into place with a light snap. ”

“ We know we are going to get a quart of berries into every pint jar, so we know just how many quarts of berries we will need to fill the necessary jars for the next winter's use.
The first thing to do is to test each jar to see that there are no cracks, no rough edges to cut the rubber, and to see whether the cover and clamp fit tightly, if a clamp type of jar is used. The bail that clamps down the glass tops should go down with a good spring. ”

“ Let them cool rapidly but be sure that no draft reaches them as a draft will cause breakage. (If there is any doubt that a bail-top jar is perfectly sealed a simple test may be made by loosening the top bail and lifting the jar by taking hold of the top with the fingers. The internal suction should hold the top tightly in place when thus lifted. If the top comes off put on a new wet rubber and sterilize 15 minutes longer for fruits.) With screw-top jars try the tops while the jars are cooling, or as soon as they [163] have cooled, and, if loose, tighten them by screwing on more closely. ”

“ Molds were improved and worker and furnace productivity increased to many times their 1800 level. New bottle shapes were introduced, and specialized and embossed bottles proliferated. The manufacture of preserve jars became a major industry, and a special “blow-back” mold, included in John Mason’s 1858 fruit jar patent, was used to form the screw threads for the sealable lids. Standard bottle shapes for different products became common, as did uniformly applied standard lip forms for different purposes. The standard shapes of the bottles from the Middleton Place privy are shown in Figure 16. ”

“ I heard him myself get it off at The Egyptian Society Dinner last month, as well as at the Annual Banquet of The Sons and Daughters of the Pre-Adamite Evolution, the month before, changing the answer, however, to "when it's a jar"—which I personally do not consider an improvement, for when a door becomes a jar I must confess I cannot see. A jar, as I understand it, is a vessel, a receptacle, a jug, a sort of demijohn, or decanter that people use to store up water, or to keep the juice of the grape in, like a pitcher, or [99] an amphora ”

“ Fill the jars to within 1⁄4 to 1⁄2 inch of tops. (In canning berries, to insure a close pack, put a 2 or 3 inch layer of berries on the bottom of the jar and press down gently with a wooden spoon. Continue in this manner with other layers until jar is filled. Fruits cut in half should be arranged with pit surface down.)
9. Add salt and boiling water to vegetables to cover them. To fruits add hot syrup or water.
10. Place wet rubber and top on jar.
11. With a bail-top jar adjust top bail only, leaving lower bail or snap, free. ”

“ GLASS JARS.--For household canning, the most acceptable containers for food are glass jars that may be closed air-tight with jar rubbers and tops. Use is sometimes made of bottles, jars, and cans of various kinds that happen to be at hand, but never should they be employed unless they can be fitted with covers and made positively air-tight. Like utensils, the glass jars that are a part of the household supply should be used from year to year, if possible, but not at the loss of material. ”

“ As you wash the jars in warm soapy water and rinse them, run your finger around the jar opening to see if there is a defect. If there is, the jar will not seal.
Look at each new metal lid to be sure the sealing compound is even and smooth. Check the metal screw band to see that it is not bent or rusty. Bands can be used over and over again. As for pretreatment of lids and bands, follow the manufacturer’s directions. ”

“ It is important to use standard jar closures. They are designed to fit home canning jars correctly, and are made from suitable materials to provide a proper seal. One of the most popular types is the two-piece lid with a metal ring or band and a flat metal disk with a sealing compound. Flat metal disks can be used only once since they may not seal properly if reused. Metal bands may be used repeatedly if they are not rusted or dented. ”

“ The open lid cast a shadow over the inside of the casing. All she saw at first was what she had seen already—the jar, and the pipe and glass funnel inserted in the cork. She removed the funnel; and, looking about her, observed on the window-sill close by a wax-tipped wand used for lighting the gas. She took the wand, and, introducing it through the aperture occupied by the funnel, moved it to and fro in the jar. The faint splash of some liquid, and the grating noise of certain hard substances which she was stirring about, were the two sounds that caught her ear. ”

“ The next day cork the jars, and either brush melted rosin over the corks, or tie a piece of moistened bladder tightly over each.
Medlar Jelly.—Fill a large jar with ripe medlars, and place it in a saucepan of boiling water; it must be large enough to allow of the water coming up to the neck of the jar, but care must be taken not to let any of the water go into it. The jar must be uncovered. Put the lid on the saucepan, and keep the water boiling until the medlars are thoroughly cooked and quite soft. Then put them into a linen jelly-bag, and let them drip into a basin ”

“ Here, for a while, we were left to ourselves; the old man placing the light in the jar, and then disappearing. He returned, carrying a long, large bamboo, and a crotched stick. Throwing these down, he poked under a pile of rubbish, and brought out a rough block of wood, pierced through and through with a hole, which was immediately clapped on the top of the jar. ”

“ Then he put the jar and the spoon back, laid the lid on the box and put it back in the chest. After that he went to the window and stood there looking out, and seemed to be very much amused with what he saw. That was all.
“Hints for me,” I remember thinking. “Perhaps it will be best not to touch the box before the moon is up to-night, and always with washed hands.” ”

“ If it is difficult to find a cool, dry place, pack the jars in a box, and fill the interstices with sand, very thoroughly dried. It is best to put jellies in tumblers, or small glass jars, so as to open only a small quantity at a time. ”

“ If, instead of drawing the knob of the jar over the surface of the glass, you only touch it here and there with it, and then throw on the mixed powders as before, separate star-shaped figures will be formed about these places. The stars will be better defined when a single powder is used; their rays are sometimes few and strong; at others, many and slight, and frequently they do not go entirely round the parts which have been touched by the phial. These different effects depend chiefly upon the quantity of the charge in the jar. ”

“ If stone jars are used, those with narrow mouths are best, as the air is most easily excluded from them; and small sized ones, containing only enough for once or twice, are best, as the frequent opening of a large jar, injures its entire contents, by the repeated admission of the air. ”