A calendar (named from the Latin calendarium, from calendce, the first day of the month), is a record or marking out of time as systematically divided into years, months, weeks, and days.
The periodical occurrence of certain natural phenomena gave rise to the first division of time, the division into weeks being the only purely arbitrary partition. The year of the ancient Egyptians was based on the changes of the seasons alone, without reference to the lunar month, and contained 365 days divided into twelve months of thirty days each, with five supplementary days at the end of the year.
The Jewish year consisted of lunar months of which they reckoned twelve in the year, intercalating a thirteenth when necessary to maintain the correspondence of the particular months with the regular recurrence of the seasons.
The Greeks in the earliest period also reckoned by lunar and intercalary months, but after one or two changes adopted the plan of Meton and Euctemon, who took account of the fact that in a period of nineteen years, the new moons return upon the same days of the year as before. This period of nineteen years was found, however, to be about six hours too long, and subsequent calculators still failed to make the beginning of the seasons return on the same fixed day of the year. Each month was divided into three decads.
The Romans at first divided the year into ten months, but they early adopted the Greek method of lunar and intercalary months, making the lunar year consist of 354, and afterwards of 355 days, leaving ten or eleven days and a fraction to be supplied by the intercalary division. This arrangement continued until the time of Julius Caesar. The first day of the month was called the calends. In March, May, July, and October the 15th, in other months the 13th, was called the ides. The ninth day before the ides (reckoning inclusive) was called the nones, being therefore either the 7th or the 5th of the month. From the inaccuracy of the Roman method of reckoning the calendar came to represent the vernalequinox nearly two months after the event, and at the request of Julius Caesar, the Greek astronomer Sosigenes with the assistance of Marcus Fabius, contrived the so-called Julian calendar. The chief improvement consisted in restoring the equinox to its proper place by inserting two months between November and December, so that the year 707 (46 BC), called the year of confusion, contained fourteen months.
In the number of days the Greek computation was adopted, which made it 365.25. To dispose of the quarter of a day it was determined to intercalate a day every fourth year between the 23rd and 24th of February. This calendar continued in use among the Romans until the fall of the empire, and throughout Christendom until 1582.
By this time, owing to the cumulative error of eleven minutes, the vernalequinox really took place ten days earlier than its date in the calendar, and accordingly PopeGregory XIII issued a brief abolishing the Julian calendar in all Catholic countries, and introducing in its stead the one now in use, the Gregorian or reformed calendar. In this way began the new style, as opposed to the other or old style. Ten days were to be dropped; every hundredth year, which by the old style was to have been a leap year, was now to be a common year, the fourth excepted; and the length of the solar year was taken to be 365 days, five hours, forty-nine minutes, and twelve seconds, the difference between which and subsequent observations is immaterial. The new calendar was adopted in Spain, Portugal, and France in 1582; in Catholic Switzerland, Germany and the Netherlands in 1583; in Poland in 1586; in Hungary in 1587; in ProtestantGermany, Holland, and Denmark in 1700; in Switzerland in 1701; in England in 1752; and in Sweden, 1753.
In the English calendar of 1752, also, the 1st of January was now adopted as the beginning of the legal year, and it was customary for some time to give two dates for the period intervening between 1st January and 25th March, that of the old and that of the new year, as January 1752/3. Russia alone retained the old style, which by 1906 differed twelve days from the new.
In France, during the revolution, a new calendar was introduced by a decree of the rational Convention, on November the 24th, 1793. The time from which the new reckoning was to commence was the autumnal equinox of 1792, which fell upon the 22nd of September, when the first decree of the new republic had been promulgated. The year was made to consist of twelve months of three decades each, and, to complete the full number, five fete days, or sansculotides (in leap years six) were added to the end of the year. The seasons and months were as follows: Autumn; 22nd September to 22nd December Vendimiaire, vintage month; Brumaire, foggy month; Frimaire, sleet month. Winter; 22nd December to 22nd March: Nivose, snowy month; Plumose, rainy month; Ventose, windy month. Spring; 22nd March to 22nd June: Germinal, budmonth; Floreal, flowermonth; Prairial, meadowmonth. Summer; 22nd June to 22nd Sept.: Messidor, harvest month; Thermidor, hot month; Fructidor, fruit month. The common Christian or Gregorian calendar was re-established in France on the 1st of January, 1806, by Napoleon. Research Calendar
The ring drop swindle was a popular confidence trick employed by criminals in Victorian London. In the swindle, a stranger makes a show of picking up a diamond ring from the floor close by to the victim. The confidence trickster then offers to sell the valuable diamond ring to the victim for a fraction of its obvious worth, on the pretext that he is far too busy to seek a more lucrative market. Naturally the ring was not found, but rather dropped deliberately by the confidence trickster, and is worth far less than the money extracted from the victim, who in fairness is swindled in part by his own greed. Research Ring Drop
The transfer of blood from one individual to another first became a practical proposition during the Great War. The recognition of four major blood groups indicated that there were limitations on blood transfusion which necessitated very careful examination of the blood of the two individuals concerned. In the early days of transfusion after preliminary grouping, the blood was transferred from the donor to the recipient by the ' direct' method, using a two-way tap and syringe, so that the blood was not exposed to the air and had no opportunity for clotting. The 'indirect' method was later introduced in which the donor's blood was received into a solution of sodium citrate which prevented it from clotting by inactivating the calcium. Within an hour or so the blood was then injected into the veins of the recipient. Prior to the second World War, most large hospital centres in Great Britain maintained a panel of blood donors who were willing to come to the hospital at any hour of the day or night for emergency transfusion. The relatives of patients also were called upon, if with the right blood group, to give their blood.
The necessities of war, and the greater demands of surgery for blood transfusion led to the establishment of ' blood banks', in which are stored large quantities of blood taken at a convenient time from thousands of volunteers. With suitable refrigeration, blood may be stored for three weeks with safety and such blood is quite suitable for the treatment of shock and conditions of blood loss. Certain other disorders, mainly medical conditions affecting the formation of red cells in the bonemarrow, are preferably treated with the transfusion of fresh blood: this seems to possess properties which become lost in storage. Blood transfusion performs a double purpose. It replaces the oxygen-carrying red cells and its fluidfraction, the plasma, contributes protein which maintains the circulating blood volume, thus preventing the escape of water into the tissues. Plasma or serum may be separated from the whole blood and dried. In this form it was used extensively during the Second World War because it could be stored indefinitely and could be reconstituted by the addition of distilled water when infusion was needed in the treatment of shock. By the extraction of the fluid portion of the whole blood, the cell content may be concentrated. Such a preparation is known as packed cells. This has become of particular value if it is necessary to raise the haemoglobin rapidly without raising the blood volume unduly. Such a procedure may be required in the treatment of severe anaemia arising from toxaemia. Research Blood Transfusion
Creosote is a generic term applied to acid liquors which are obtained during the destructive distillation of wood, and also to a fraction obtained in the distillation of coal-tar. Creosote was discovered by Reichenbach about 1831 in wood-tar, from which it may be separated by a tedious process. It is generally obtained, however, from the products of the destructive distillation of wood. In a pure state it is oily, heavy, colourless, has a sweetish burning taste and a strong smell of peat smoke or smoked meat. It is a powerful antiseptic. Wood treated with it is not subject to dry-rot or other disease. Creosote has been used in surgery and medicine with great success. Research Creosote
Ductility is the property of solid bodies, particularly metals, which renders them capable of being extended by drawing, while their thickness or diameter is diminished, without any actual fraction or separation of their parts. On this property the wire-drawing of metals depends. The following is nearly the order of ductility of the metals which possess the property in the highest degree, that of the first mentioned being the greatest; gold, silver, platinum, iron, copper, zinc, tin, lead, nickel, palladium, cadmium. The ductility of glass at high temperatures seems to be unlimited, while its flexibility increases in proportion to the fineness to which its threads are drawn. Research Ductility
In arithmetic and algebra, a fraction is a combination of numbers representing one or more parts of a unit or integer: thus, four-fifths (4/5) is a fraction formed by dividing a unit into five equal parts, and taking one part four times.
Fractious are divided into vulgar and decimal. Vulgar fractions are expressed by two numbers, one above another, with a line between them. The lower, the denominator, indicates into how many equal parts the unit is divided; and the number above the line, called the numerator, indicates how many of such parts are taken.
A proper fraction is one whose numerator is less than its denominator. An improper fraction is one whose numerator is not less than its denominator, as (8/5).
A simple fraction expresses one or more of the equal parts into which the unit is divided, without reference to any other fraction.
A compound, fraction expresses one or more of the equal parts into which another fraction or a mixed number is divided. Compound fractions have the word of interposed between the simple fractions of which they are composed: thus 1/3 of 4/5 of 1 4/7is a compound fraction.
A complex fraction is that which has a fraction either in its numerator or denominator, or in each of them.
In decimal fractions the denominator is 10, or some number produced by the continued multiplication of 10 as a factor, such as 100, 1000, etc; hence, there is no necessity for writing the denominator, and the fraction is usually expressed by putting a point (•) before the numerator, as 0.5 - 5/10. All calculations are much simplified in decimal fractions; yet, simple as the system is, it was only discovered first in the 15th century by the German mathematician Regiomontanus. Research Fraction
Gas is an elastic aeriform fluid, a term originally synonymous with air, but afterwards restricted to such bodies as were supposed to be incapable of being reduced to a liquid or solid state. Under this supposition gas was a term applied to all permanently elastic fluids or airs differing from common air. After the liquefaction of gases by Faraday, the old distinction between gas and vapour, that the latter could be reduced to a liquid or solid condition by reduction of temperature and increase of pressure, while a gas could not be so altered, was no longer tenable, so that the term resumed nearly its original signification, and designates any substance in an elastic aeriform state.
Gases are distinguished from liquids by the name of elastic fluids; while liquids are termed non-elastic, because they have, comparatively, no elasticity. But the most promient distinction is the following: Liquids may be compressed to a slight extent, but when the pressure is released they return to their original condition, and in so far they are elastic; but gases when left unconfined expand in every direction. In respect of this expansiveness, all gaseous bodies obey more or less strictly two laws, commonly called the 'gaseous laws'.
The first, known as Boyle's Law, given first by Robert Boyle in 1662, and then by Mariotte in 1676, is that 'The volimie of a given mass of gas varies inversely with the pressure to which the gas is subjected'.
The second of the gaseous laws is that of Charles or Gay-Lussac. Dalton published it in 1801; but Gay-Lussac, who stated it in 1802, gives the credit of having discovered it, fifteen years previously, to Citizen Charles. The law may be stated as follows: 'The volume of a gas maintained under constant pressure increases for equal increments of temperature by a constant fraction of its original volume; and this fraction is the same whatever is the nature of the gas. A mass of gas, whose volume is 273 at 0 degrees C., becomes 274 at 1 degree, and 373 at 100 degrees, the pressure remaining constant'. This law may also be stated in the form - the volume of a given mass of any gas is directly proportional to the absolute temperature of the gas, provided the pressure remain constant. The absolute temperature is obtained by adding 273 degrees to the temperature in degrees centigrade, since the absolute zero is -273 degrees C.
In virtue of these laws a gas may now be defined to be a substance possessing the condition of perfect fluidelasticity, and presenting under a constant pressure a uniform state of expansion for equal increments of temperature - a property distinguishing it from vapour. There is, however, no known gas that obeys these two laws perfectly: thus, of the six gases oxygen, hydrogen, nitrogen, carbon monoxide, nitric oxide, and methane, all except hydrogen are more compressible than they should be theoretically, while hydrogen deviates slightly in the opposite direction, being less compressible than Boyle's law would indicate. The other gases exhibit even greater deviations from Boyle's law, and the amount of the deviation rapidly increases as the gas is brought nearer and nearer to liquefaction.
Charles' law, according to which equal rises in temperature should produce equal increments in volume, does not hold absolutely for all gases, and the deviations become greater as the point of liquefaction is approached. Characteristic of gases is the fact that they all possess a critical point or critical temperature, at which all distinction between the liquid and gaseous phases disappear wlien a suitable pressure (the critical pressure) is used. This was first observed by Andrews for carbon dioxide, the critical temperature of which is 31.3 degrees C, and its critical pressure 72.9 atmospheres. The liquefaction of gases is effected by the aid of low temperature and high pressure.
Petroleum refining is the processes used to produce fuels, chemicals, and gas by treatment of petroleum. Petroleum has been known and used for thousands of years, but systematic separation of its components has only been carried out for just over a century. Initially, petroleum was refined almost entirely to produce fuels. Since the Second World War the use of refinery products as a source of petrochemicals has become more important, but over 90 percent of crude petroleum is still used for fuel. The key to petroleum refining is the initial separation of hydrocarbons into various groups of similar compounds. The groups are distinguished by their boiling-points, and they are separated by fractional distillation. A group of hydrocarbons with similar boiling-points is called a fraction. Each fraction has a distinct treatment within the refinery. Fractions for which there is little demand may be converted to other fractions by later refinery processes. Refinery gas is the petroleumfraction with the lowest boiling-point, and does not condense in a fractional distillation column.
Propane and butane may be extracted from refinery gas to make liquefied petroleum gas. The residual gas, containing mainly hydrogen, methane, and ethane, is used as a fuel to operate the refinery. The most economically important product of petroleum refining is the range of fractions called petrol, which boils at 30-140 degrees Celsius. Light petrol condenses at boiling-points of 30-80 degrees Celsius, right at the top of the fractionation column. It is used to make fuel for motor cars and other petrol-engined vehicles. Next down the column, at boiling- points of 80-190 degrees Celsius, naphthas are drawn off. They may be used in blending fuels. Individual naphthas are separated and used to make solvents, and as a raw material in producing many organic chemicals. Much of the naphtha fraction is reformed for use in petrol. The fraction next below the naphthas in the fractionation column condenses at boiling-points of 190-250 degrees Celsius. This fraction contains the kerosenes, which include paraffin, traditionally burnt with a wick for heating and lighting. This fraction is now more important for making aviation fuel for jet aircraft. The final group of fractions condensing in the column is diesel oil, or gas oil, with boiling-points in the range 250-350 degrees Celsius. Their main use is in diesel engines.
Heavier oil which does not evaporate in the initial fractional distillation passes through the bottom of the column. In some refineries these residues pass on to another stage of vacuumdistillation. Products separated this way include lubricating oils and petroleum jelly (used as a grease, or as a base for making ointments). Separating individual compounds from the various fractions and residues is done by several methods. Solvent extraction, for example, is another way of extracting lubricating oil from residues. Further solvent treatment can eliminate undesirable contaminants from lubricating oil or kerosenes. Some substances are removed or separated by crystallization, in which the heavier fractions are cooled until waxes crystallize, and other semi-solids solidify. The solid particles are then filtered out. Preparing fractions or products for final use involves many complicated processes. Impurities, of which the most important are sulphur compounds, are generally removed by hydro treatment.
In blending, different fractions are mixed to achieve specific properties. For example, fuel-oils for domestic and industrial heating are a blend of heavy residue oils with lighter fractions which reduce their viscosity. Oils to be burnt in engines generally need fuel additives blended in to improve their performance and safety. Chemical treatment of fractions to change them into other fractions or into feedstocks for petrochemicals is a large and growing part of refinery work. These processes include cracking, in which heavier hydrocarbons in residues are broken down into lighter fractions, particularly petrol. In hydro treatment, unsaturated hydrocarbons may be saturated with hydrogen. To make slightly heavier hydrocarbons, or to turn straight-chain molecules into ring molecules, a reforming process is used. This produces more petrol, and many aromatic hydrocarbons for use in the chemical industry to make explosives, synthetic rubbers, food preservatives, and many other specialist chemicals.
Other building-up processes include polymerisation, in which identical molecules combine, and alkylation, in which hydrocarbon groups or chains are added to molecules. Storage facilities are a vital part of the work of a refinery, which may have hundreds of tanks, generally above ground and about 30 metres in diameter. A huge network of pipes connects the tanks with various processes, so that a tank may be used for storing intermediate fractions, separate compounds, or finished product awaiting transport to users or chemical factories. Large tanks hold the crude oil delivered to the refinery, with each tank used for oil from a particular source. Switching between crude tanks enables selection of the crude to give the properties best suited to the refinery's current workload. Transport of crude to the refinery is by pipeline or by oil tanker (most refineries are near the sea). Transport of finished products is generally by pipeline, road, or rail. Research Petroleum Refining
Fractional banking is a banking practice that some governments impose on their banks, calling for a fixed fraction between cash reserves and total liabilities. Research Fractional Banking
Free-trade is the term applied to national commerce when relieved from such interference as is intended to improve or otherwise influence it; that is, unrestricted by laws or tariffs, and not unduly stimulated by bounties. In all countries it was long held to be of importance to encourage native production and manufactures by excluding from their own markets, and from the colonial markets over which they had control, the competing produce and manufactures of other countries. On this theory the great body of British commercial legislation was founded until 1846, when the policy of free-trade was introduced in grain, and afterwards gradually extended by the repeal of the navigation laws in 1849 and other great measures, until nearly all British commercial legislation has been brought into conformity with it., though Britain was alone in the world in allowing free-trade at the time.
As an economic principle free-trade is the direct opposite to the principle or system of protection, which maintains that a state can reach a high degree of material prosperity only by protecting its domestic industries from the competition of all similar foreign industries. To effect this protecting countries either prohibit the importation of foreign goods by direct legislation, or impose such duties as shall, by enhancing the price, check the introduction of foreign goods. The advocates of what is called fair trade in Britain professed a preference for free-trade were it universal or even common; but seeing that Britain was almost the sole free-trade country in the world, declared that a policy of reciprocity was required for the protection of British traders and manufacturers. Supportes of free-trade cited the progress made by Britain since 1846 as adduced as a striking proof of the wisdom of a free-trade policy, even without reciprocity, however, after the development of other nations following the Second World War, the situation changed with low-cost labour in other countries providing competing goods at a fraction of the price of the domestic equivalent. Research Free-Trade
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Calendar
