Assaying is the estimation of the amount of pure metal, and especially of the precious metals, in an ore or alloy. In the case of silver the assay is either by the dry or by the wet process. The dry process is called eupellation from the use of a small and very porous cup, called a cupel, which is usually made of well-burned and finely-ground bone-ash or of magnesia. The cupel, being thoroughly dried, is placed in a fire-clay oven about the size of a drain-tile, with a flat sole and arched roof, and with slits at the sides to admit air. This oven, called a muffle, is set in a furnace, and when it is at a red heat the assay, consisting of a small weighed portion of the alloy wrapped in sheet-lead, is laid upon the cupel. The heat causes the lead to volatilize or combine with the other metals, and to sink with them into the cupel, leaving a bright globule of pure metallic silver, which gives the amount of silver in the alloy operated on. In the wet process the alloy is dissolved in nitric acid, and to the solution are added measured quantities of a solution of common salt of known strength, which precipitates chloride of silver. The operation is concluded when no further precipitate is obtained on the addition of the salt solution, and the quantity of silver is calculated from the amount of salt solution used.
An alloy of gold is first cupelled with lead as above, with the addition of three parts of silver for every one of gold. After the cupellation is finished the alloy of gold and silver is beaten and rolled out into a thin plate, which is curled up by the fingers into a little spiral or cornet. This is put into a flask with nitric acid, which dissolves away the silver and leaves the cornet dark and brittle. After washing with water the cornet is boiled with stronger nitric acid to remove the last traces of silver, well washed, and then allowed to drop into a small crucible, in which it is heated, and then it is weighed. The assay of gold, therefore, consists of two parts: cupellation, by which inferior metals (except silver) are removed; and quartation, by which the added silver and any silver originally present are got rid of. The quantity of silver added has to be regulated to about three times that of the gold. If it be more the cornet breaks up, if it be less the gold protects small quantities of the silver from the action of the acid. Where, as in some gold manufactured articles, these methods of assay cannot be applied, a streak is drawn With the article upon a touchstone consisting of coarse-grained Lydian quartz saturated with bituminous matter, or of black basalt. The practised assayer will detect approximately the richness of the gold from the colour of the streak, which may be further subjected to an acid test. The Goldsmith's Company of London is the statutory assay-master of all England. Research Assaying
In agriculture, draining is a method of improving the soil by withdrawing the water from it by means of channels that are generally covered over. The successful practice of draining in a great measure depends on a proper knowledge of the superficial strata, of their situation, relative degrees of porosity, etc. Some strata allow water to pass through them, while others more impervious force it to run or filtrate along their surfaces until it reaches more level ground below. In general where the grounds are in a great measure flat and the soils of materials which retain the excess of moisture, they require artificial means of drainage to render them capable of yielding good crops whether of' grain or grass.
The wetness of land which makes it inferior for agricultural purposes, may appear not only as surface-water but as water which flows through the lower strata, and to draw off these there are the two distinct operations of surface-draining' and under-draining. The rudest form of open drains are the deep furrows lying between high-backed ridges, and meant to carry off the surplus water after the soil is completely saturated, but in doing so they generally carry off also much of the best of the soil and of the manure which has been spread upon it. The ordinary ditch is a common form of water-course useful in certain cases, as in hill pastures. But covered drains at a depth of one metre or so are the common forms in draining agricultural lands. They are generally either stone-drains or tile-drains. Stone-drains are either formed on the plan of open culverts of various forms, or of small stones in sufficient quantity to permit a free and speedyfiltration of the water through them. The box-drain, for instance, is formed of flat stones neatly arranged in the bottom of the trench, the whole forming an open tube.
In tile-drains, tiles or pipes of burnt clay are used for forming the conduits. They possess all the qualities which are required in the formation of drains, affording a free ingress to water, while they effectually exclude vermin, earth, and other injurious substances.
Drainage tiles and pipes have been made in a great variety of forms, the earliest of which, since the introduction of thorough draining, was the horse-shoe tile, so called from its shape. These should always rest on soles, or flats of burned clay. Pipetiles, which combine the sole and cover in one piece, have been made of various shapes, but the best form appears to be the cylinder.
An important department of draining is the draining off of the waters which are the sources of springs. Sometimes the judicious application of a few simple drains, made to communicate with the watery layers, will often dry swamps of great extent, where large sums of money, expended in forming open drains in the swamp itself, would leave it but little improved.
In the laying out of drains the first point to be determined is the place of outfall, which should always afford a free and clear outlet to the drains, and must necessarily be at the lowest point of the land to be drained. The next point to be determined is the position of the minor drains; in the laying out of which the surface of each field must be regarded as being made up of one or more planes, as the case may be, for each of which the drains should be laid out separately. Level lines are to be set out a little below the upper edge of each of these planes, and the drains must then be made to cross these lines at right angles. By this means the drains will run in the line of the greatest slope, no matter how distorted the surface of the field may be. All the minor drains should be made to discharge into mains or submains, and not directly into an open ditch or water-course. As a general rule there should be a main to receive the waters of the minor drains from every 5 acres.
The advantages of drainage are obvious. In the first place it allows the soil to be brought into a more suitable condition for the growth of plants, aiding in producing the finely-divided and porous state by which the roots and rootlets can spread themselves at will in order to obtain the needed supplies of food, air, and moisture. It also allows the sun's rays to produce their full effect on the soil and plants without being robbed of great part of it by the stagnant water. Research Draining
The bullfinch (Pyrrhula pyrrhula) is a an insessorialbird, a species of finch of the family Fringillidae, with a short thick rounded bill, beak and crown of the head black, body bluish-gray above and bright tile-red below. It occurs in Britain, in the middle and south of Europe, and in Asia, and when tamed may be taught to sing musical airs. Pyrrhula synoica is an Asiatic species, and Pyrrhula cineriola an inhabitant of Brazil. Research Bullfinch
The tile-fish (Lopholatilus chamaeleonticeps) is a large, deep-water, yellow-spotted, spinny-finned fish of the order Teleostei found off the coast of New England. The tile-fish grows to about 30 cm long and is closely related to the sea perches. It is apparently good to eat. Research Tile-fish
The GIMP (GIMP is an acronym for GNU Image Manipulation Program) is a computer software application that started as an undergraduate project by Peter Mattis and Spencer Kimball at the University of California and has evolved into an application designed for retouching photographs, composing and authoring images. Its powerful capabilities as an image manipulation program make it a worthy competitor to other similar programs such as AdobePhotoshop or Corel PhotoPaint, but the biggest advantage of The GIMP is it's free availability although it's not freeware, rather it is an OSS (Open Source Software) program covered by the GPL license, which gives the user the freedom to access and also to change the source code that makes up the program. The Gimp offers a full suite of painting tools including brushes, a pencil, an airbrush, an ink tool, and cloning. Tile-based memory management so image size is limited only by available disk space; sub-pixel sampling for all paint tools, allowing for high-quality anti-aliasing; full Alpha channel
(transparency) support; layers and channels. Advanced scripting capabilities provided by a procedural database so you can call internal GIMP functions from external scripts, such as Script-Fu, Perl-Fu (Perl scripts) and Python-Fu (Python scripts). The GIMP offers multiple undo and redo, limited only by disk space; transformation tools including rotate, scale, shear, and flip. File formats supported include PostScript, JPEG, GIF, PNG, XPM, TIFF, TGA, MPEG, PCX, BMP and many others. Selection tools including rectangular, elliptical, free, fuzzy, paths, and intelligent scissors. The GIMP supports plug-ins that allow for the easy addition of new functions, new file formats, and new effects filters. The GIMP is probably best known for its use on the GNU/Linux platform, but there are many platforms that GIMP can run on, including GNU/Linux, Microsoft Windows 95, 98, NT4 and 2000, OpenBSD, NetBSD, FreeBSD, Solaris, SunOS, AIX, HP-UX, Tru64, Digital Unix, OSF/1, IRIX, OS/2 and BeOS. Research Gimp
Phosphoric acid can exist as a crystal or clear liquid. It is an oily, thick, colourless, and odourless liquid, or a thick, colourless, unstable crystalline solid. It is used in the manufacture of phosphates, such as salts, soaps, and detergents; fertilizers; yeasts; fire control agents; opalglass; electric lights; dental cements; waxes and polishes; gelatin; ethylbenzene, propylene, and cumene; and soft drinks. It is used as an acidcatalyst, soil stabilizer, antioxidant in food, acidulant and flavour agent in jellies and preserves, bonding agent for refractory bricks, and petrol additive. It is also used in the rust proofing and polishing of metals, cottondyeing, tile cleaning, extracting penicillin, hot stripping for aluminium and zinc substrates, ceramic binding, water treatment, process engraving, electro-polishing, coagulating of rubberlatex, operating lithography and photoengraving operations, and pickling. It is used to manufacture the phosphoric acidelectrolyte fuel cell system which has created the largest fuel cell built and has been used to treat lead poisoning.
Phosphoric acid is incompatible with strong caustics and most metals. It readily reacts with metals to form flammable hydrogen gas. The liquid can solidify at temperatures below 21 degrees C. It is corrosive to ferrous metals and alloys. It is soluble in alcohol and hot water. It can form three series of salts: primary phosphates, dibasic phosphates, and tribasic phosphates. It is deliquescent and hygroscopic. It is a chelating agent. It has a low vapour pressure at room temperature. Phosphoric acid is also known as orthophosphoric acid, metaphosphoric acid, and white phosphoric acid. Research Phosphoric acid
Coalbrookdale is a village in Shropshire, England on the River Severn some 16 km south-east of Shrewsbury. It was once an important coal mining area, but the coal was exhausted by the 20th century and iron ore and limestone mining took over. It has been famous for its iron, brick and tile works for a few hundred years. Research Coalbrookdale
Abbreviations
Research Assaying
