Cattle—colloquially cows—are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, are most classified collectively as Bos taurus. Cattle are raised as livestock for meat, for milk, for hides, which are used to make leather, they are used as riding animals and draft animals. Another product of cattle is dung, which can be used to create fuel. In some regions, such as parts of India, cattle have significant religious meaning. Cattle small breeds such as the Miniature Zebu, are kept as pets. Around 10,500 years ago, cattle were domesticated from as few as 80 progenitors in central Anatolia, the Levant and Western Iran. According to an estimate from 2011, there are 1.4 billion cattle in the world. In 2009, cattle became one of the first livestock animals to have a mapped genome; some consider cattle the oldest form of wealth, cattle raiding one of the earliest forms of theft. Cattle were identified as three separate species: Bos taurus, the European or "taurine" cattle.
The aurochs is ancestral to both taurine cattle. These have been reclassified as one species, Bos taurus, with three subspecies: Bos taurus primigenius, Bos taurus indicus, Bos taurus taurus. Complicating the matter is the ability of cattle to interbreed with other related species. Hybrid individuals and breeds exist, not only between taurine cattle and zebu, but between one or both of these and some other members of the genus Bos – yaks and gaur. Hybrids such as the beefalo breed can occur between taurine cattle and either species of bison, leading some authors to consider them part of the genus Bos, as well; the hybrid origin of some types may not be obvious – for example, genetic testing of the Dwarf Lulu breed, the only taurine-type cattle in Nepal, found them to be a mix of taurine cattle and yak. However, cattle cannot be hybridized with more distantly related bovines such as water buffalo or African buffalo; the aurochs ranged throughout Europe, North Africa, much of Asia. In historical times, its range became restricted to Europe, the last known individual died in Mazovia, Poland, in about 1627.
Breeders have attempted to recreate cattle of similar appearance to aurochs by crossing traditional types of domesticated cattle, creating the Heck cattle breed. The noun cattle encompasses both sexes; the singular, technically means the female, the male being bull. The plural form cows is sometimes used colloquially to refer to both sexes collectively, as e.g. in a herd, but that usage can be misleading as the speaker's intent may indeed be just the females. The bovine species per se is dimorphic. Cattle did not originate as the term for bovine animals, it was borrowed from Anglo-Norman catel, itself from medieval Latin capitale'principal sum of money, capital', itself derived in turn from Latin caput'head'. Cattle meant movable personal property livestock of any kind, as opposed to real property; the word is a variant of chattel and related to capital in the economic sense. The term replaced earlier Old English feoh ` property', which survives today as fee; the word "cow" came via Anglo-Saxon cū, from Common Indo-European gʷōus = "a bovine animal", compare Persian: gâv, Sanskrit: go-, Welsh: buwch.
The plural cȳ became ki or kie in Middle English, an additional plural ending was added, giving kine, but kies and others. This is the origin of the now archaic English plural, "kine"; the Scots language singular is coo or cou, the plural is "kye". In older English sources such as the King James Version of the Bible, "cattle" refers to livestock, as opposed to "deer" which refers to wildlife. "Wild cattle" may refer to undomesticated species of the genus Bos. Today, when used without any other qualifier, the modern meaning of "cattle" is restricted to domesticated bovines. In general, the same words are used in different parts of the world, but with minor differences in the definitions; the terminology described here contrasts the differences in definition between the United Kingdom and other British-influenced parts of the world such as Canada, New Zealand and the United States. An "intact" adult male is called a bull. A wild, unmarked bull is known as a micky in Australia. An unbranded bovine of either sex is called a maverick in the Canada.
An adult female that has had a calf is a cow. A young female before she has had a calf of her own and is under three years of age is called a heifer. A young female that has had only one calf is called a first-calf heifer. Young cattle of both sexes are called calves until they are weaned weaners until they are a year old in some areas. After that, they are referred to as stirks if between one and two years of age. A castrated male is called a steer in the United States.
Otto Frederick Hunziker
Otto Frederick Hunziker was a pioneer in the American and international dairy industry, as both an educator and a technical innovator. Hunziker was born and raised in Switzerland, emigrated to the U. S. and studied at Cornell University. He started and developed the dairy program at Purdue University when such programs were at their infancy. At this same time, Hunziker was involved with the development of the American Dairy Science Association and the standardization and improvement of many dairy tests and processes. Hunziker wrote several of the leading dairy processing texts. After leaving Purdue University, Hunziker managed research and operations at a large, national condensary, continued to drive ADSA's standardization and publishing efforts, represented the U. S. at international dairy congresses, facilitated dairy industry improvements across the globe. Otto Frederick Hunziker was born in Zürich, Switzerland, on 25 December 1873 to Karl Otto and Luise Hunziker. Otto's siblings were Karl Rudolf, Barbara Luise, Marie Julie.
Hunziker spent many early years in Goldbach, where his father was a pastor and member of the canton parliament. Otto attended the two-year course of studies at Strickhof Agricultural College in Zürich, graduating at age 19. In 1893, Otto Frederick Hunziker emigrated to the United States. During this time period, significant new development in dairy processing technology was occurring on both sides of the Atlantic Ocean. In 1890, Stephen Babcock published specifications for the Babcock test for milk fat content. In 1892, Dr. Niklaus Gerber acquired a Swiss patent on the Gerber method for analyzing fat content in milk. Dr. Gerber was based in Zürich, had studied at the University of Zürich, worked for two years at the Swiss-American Milk Company in Little Falls, New York. Hunziker would spend a substantial amount of time improving these analytic methods. In the United States, Hunziker worked for two years as a laborer on a dairy farm near Attleboro, Massachusetts. To improve his English and commercial skills, he studied at Bryant and Stratton Business College, Rhode Island in 1896.
He returned to Switzerland in 1898 before returning to receive a B. S. Agriculture in 1900 and M. S. A. in 1901 from Cornell University. He served as an assistant in charge of dairy bacteriology at Cornell University until 1902, when he equipped and operated a dairy manufacturing research laboratory for the Scranton Condensed Milk Company in Ellicottville, New York. Otto Frederick married Florence Belle Burne on 10 April 1905 in Portville, Cattaraugus County, New York. In 1905 Hunziker accepted a position at Purdue University in West Lafayette, Indiana as head of Purdue's Dairy Department. Dairy departments were new at American colleges. Hunziker led Purdue's dairy department through significant growth. In the summer of 1906, Hunziker was among 18 teachers and investigators meeting at the University of Illinois, Urbana, to found what was known as National Association of Dairy Instructors and Investigators. From 1910 to 1926, Hunziker chaired ADSA's Committee on Official Methods of Testing Milk and Cream for Butterfat.
In 1911, this committee met in Washington, D. C. with the U. S. Bureau of Dairying, the U. S. Bureau of Standards and manufacturers of glassware. Standard specifications for Babcock glassware were published as a result of this meeting. Hunziker pursued numerous improvements to the testing methodology, which improved the quality and safety of dairy products. Hunziker was the third president of ADSA from 1910 through 1911. During Hunziker's presidency, ADSA also: created a national score card for scoring dairies. Apart from application of improved pedagogy and scientific methodology, Hunziker oversaw planning and construction of Smith Hall, the building which thereafter housed Purdue's dairy manufacturing group, extension service, creamery. While at Purdue, he published over 50 bulletins and scientific treatises addressing dairy farm and plant problems. In 1917, Hunziker left Purdue to manage manufacturing and research at the Blue Valley Creamery Company in Chicago, Illinois. Hunziker wrote dairy articles and textbooks used throughout the world, developed dairy curricula, advocated for dairy laws, developed standard testing methodology.
In particular, Hunziker authored The Butter Industry, Prepared for Factory and Laboratory, a well-known text in the industry that enjoyed at least three editions. A book that Hunziker self-published in 1914, "Condensed Milk and Milk Powder: Prepared for the Use of Milk Condenseries, Dairy Students and Pure Food Departments", was republished in a seventh edition in October 2007 by Cartwright Press. According to one book review: "The popularity of this book may be judged by the fact that this is the fourth edition, the three previous editions having long since been exhausted; the book is the most important contribution on the condensed milk powder industry. It should be in the library of the teacher, the student or factory man interested in any phase of the
Cream is a dairy product composed of the higher-butterfat layer skimmed from the top of milk before homogenization. In un-homogenized milk, the fat, less dense rises to the top. In the industrial production of cream, this process is accelerated by using centrifuges called "separators". In many countries, it is sold in several grades depending on the total butterfat content, it can be dried to a powder for shipment to distant markets, contains high levels of saturated fat. Cream skimmed from milk may be called "sweet cream" to distinguish it from cream skimmed from whey, a by-product of cheese-making. Whey cream has a lower fat content and tastes more salty, tangy and "cheesy". In many countries, cream is sold fermented: sour cream, crème fraîche, so on. Both forms have many culinary uses in sweet, bitter and tangy dishes. Cream produced by cattle grazing on natural pasture contains some natural carotenoid pigments derived from the plants they eat; this is the origin of butter's yellow color. Cream from goat's milk, or from cows fed indoors on grain or grain-based pellets, is white.
Cream is used as an ingredient in many foods, including ice cream, many sauces, stews and some custard bases, is used for cakes. Whipped cream is served as a topping on ice cream sundaes, lassi, sweet pies, blueberries or peaches. Irish cream is an alcoholic liqueur which blends cream with whiskey, honey, wine, or coffee. Cream is used in Indian curries such as masala dishes. Cream is added to coffee in the US and Canada. Both single and double cream can be used in cooking. Double cream or full-fat crème fraîche are used when cream is added to a hot sauce, to prevent any problem with it separating or "splitting". Double cream can be thinned with milk to make an approximation of single cream; the French word crème denotes not only dairy cream, but other thick liquids such as sweet and savory custards, which are made with milk, not cream. Different grades of cream are distinguished by their fat content, whether they have been heat-treated, so on. In many jurisdictions, there are regulations for each type.
The Australia New Zealand Food Standards Code – Standard 2.5.2 – Defines cream as a milk product comparatively rich in fat, in the form of an emulsion of fat-in-skim milk, which can be obtained by separation from milk. Cream must contain no less than 350 g/kg milk fat. Manufacturers labels may distinguish between different fat contents, a general guideline is as follows: Canadian cream definitions are similar to those used in the United States, except for "light cream", low-fat cream with 5% or 6% butterfat. Specific product characteristics are uniform throughout Canada, but names vary by both geographic and linguistic area and by manufacturer: "coffee cream" may be 10% or 18% and "half-and-half" may be 3%, 5%, 6% or 10%, all depending on location and brand. Cream in Canada is defined to be the liquid obtained from milk after separating the various components to increase the milk fat content. Canadian Food and Drug Regulations allow stabilizers and acidity regulators. For heat-treated whipping cream, regulations disallow more than 0.25% skim milk powder, 0.1% glucose solids, 0.005% calcium sulphate, 0.2% microcrystalline cellulose, 0.02% xanthan gum.
The content of milk fat present in canned cream must be displayed as a percentage followed by "milk fat", "B. F", or "M. F". Fat content may be displayed on canned cream in Canada. In France, the use of the term "cream" for food products is defined by the decree 80-313 of April 23, 1980, it specifies the minimum rate of milk fat as well as the rules for pasteurisation or UHT sterilisation. The mention "crème fraîche" can only be used for pasteurised creams conditioned on production site within 24h after pasteurisation. If food additives complying with French and European laws are allowed none will be found in plain "crèmes" and "crèmes fraîches" apart from lactic ferments. Fat is displayed "XX% M. G." for "matière grasse" on packagings. In Japan, cream sold in supermarkets is between 35% and 48% butterfat. Russia, as well as other EAC countries separates cream into two classes: normal and heavy, but the industry has pretty much standardized around the following types: In Sweden, cream is sold as: Matlagningsgrädde, 10–15 % Kaffegrädde, 10-12 %, earlier 12 % Vispgrädde, 36–40 %, the 36 % variant has additives.
Mellangrädde is, nowadays, a less common variant. Gräddfil and Creme Fraiche are two common sour cream products. In Switzerland, the types of cream are defined as follows: Sour cream and crème fraîche are defined as cream soured by bacterial cultures. Thick cream is defined as cream thickened using thickening agents. In the United Kingdom, the types of cream are defined as followed: In the United States, cream is sold as: Most cream products sold in the United States at retail contain the minimum permissible fat content for their product type, e.g. "Half and half" always contains only 10.5% butterfat. Not all grades are defined by all jurisdiction
United States Department of Agriculture
The United States Department of Agriculture known as the Agriculture Department, is the U. S. federal executive department responsible for developing and executing federal laws related to farming and food. It aims to meet the needs of farmers and ranchers, promote agricultural trade and production, work to assure food safety, protect natural resources, foster rural communities and end hunger in the United States and internationally. 80% of the USDA's $141 billion budget goes to the Food and Nutrition Service program. The largest component of the FNS budget is the Supplemental Nutrition Assistance Program, the cornerstone of USDA's nutrition assistance; the current Secretary of Agriculture is Sonny Perdue. Many of the programs concerned with the distribution of food and nutrition to people of America and providing nourishment as well as nutrition education to those in need are run and operated under the USDA Food and Nutrition Service. Activities in this program include the Supplemental Nutrition Assistance Program, which provides healthy food to over 40 million low-income and homeless people each month.
USDA is a member of the United States Interagency Council on Homelessness, where it is committed to working with other agencies to ensure these mainstream benefits are accessed by those experiencing homelessness. The USDA is concerned with assisting farmers and food producers with the sale of crops and food on both the domestic and world markets, it plays a role in overseas aid programs by providing surplus foods to developing countries. This aid can go through USAID, foreign governments, international bodies such as World Food Program, or approved nonprofits; the Agricultural Act of 1949, section 416 and Agricultural Trade Development and Assistance Act of 1954 known as Food for Peace, provides the legal basis of such actions. The USDA is a partner of the World Cocoa Foundation. Early in its history, the economy of the United States was agrarian. Officials in the federal government had long sought new and improved varieties of seeds and animals for import into the United States. In 1837 Henry Leavitt Ellsworth, a Yale-educated attorney interested in improving agriculture, became Commissioner of Patents, a position within the Department of State.
He began collecting and distributing new varieties of seeds and plants through members of the Congress and agricultural societies. In 1839, Congress established the Agricultural Division within the Patent Office and allotted $1,000 for "the collection of agricultural statistics and other agricultural purposes." Ellsworth's interest in aiding agriculture was evident in his annual reports that called for a public depository to preserve and distribute the new seeds and plants, a clerk to collect agricultural statistics, statewide reports about crops in different regions, the application of chemistry to agriculture. Ellsworth was called the "Father of the Department of Agriculture."In 1849, the Patent Office was transferred to the newly created Department of the Interior. In the ensuing years, agitation for a separate bureau of agriculture within the department or a separate department devoted to agriculture kept recurring. On May 15, 1862, Abraham Lincoln established the independent Department of Agriculture to be headed by a commissioner without Cabinet status, the agriculturalist Isaac Newton was appointed to be the first such commissioner.
Lincoln called it the "people's department." In 1868, the Department moved into the new Department of Agriculture Building in Washington, D. C. designed by famed DC architect Adolf Cluss. Located on Reservation No.2 on the National Mall between 12th Street and 14th SW, the Department had offices for its staff and the entire width of the Mall up to B Street NW to plant and experiment with plants. In the 1880s, varied advocacy groups were lobbying for Cabinet representation. Business interests sought a Department of Commerce and Industry, farmers tried to raise the Department of Agriculture to Cabinet rank. In 1887, the House of Representatives and Senate passed bills giving Cabinet status to the Department of Agriculture and Labor, but the bill was defeated in conference committee after farm interests objected to the addition of labor. On February 9, 1889, President Grover Cleveland signed a bill into law elevating the Department of Agriculture to Cabinet level. In 1887, the Hatch Act provided for the federal funding of agricultural experiment stations in each state.
The Smith-Lever Act of 1914 funded cooperative extension services in each state to teach agriculture, home economics, other subjects to the public. With these and similar provisions, the USDA reached out to every county of every state. During the Great Depression, farming remained a common way of life for millions of Americans; the Department of Agriculture's Bureau of Home Economics, established in 1923, published shopping advice and recipes to stretch family budgets and make food go farther. USDA helped ensure that food continued to be produced and distributed to those who needed it, assisted with loans for small landowners, contributed to the education of the rural youth, it was revealed on August 27th, 2018 that the U. S. Department of Agriculture would be providing U. S. farmers with a farm aid package, which will total $4.7 billion in direct payments to American farmers. This package is meant to offset the losses farmers are expected to incur from retaliatory tariffs placed on American exports during the Trump tariffs.
The Department of Agriculture was authorized a budget for Fiscal Year 2015 of $139.7 billion. The budget authorization is broken down as follows: Agricultural Stabilization and Conservation Service Animal Damage Control (
A centrifuge is a piece of equipment that puts an object in rotation around a fixed axis, applying a force perpendicular to the axis of spin that can be strong. The centrifuge works using the sedimentation principle, where the centrifugal acceleration causes denser substances and particles to move outward in the radial direction. At the same time, objects that are less dense move to the center. In a laboratory centrifuge that uses sample tubes, the radial acceleration causes denser particles to settle to the bottom of the tube, while low-density substances rise to the top. There are three types of centrifuge designed for different applications. Industrial scale centrifuges are used in manufacturing and waste processing to sediment suspended solids, or to separate immiscible liquids. An example is the cream separator found in dairies. High speed centrifuges and ultracentrifuges able to provide high accelerations can separate fine particles down to the nano-scale, molecules of different masses.
Large centrifuges are used to simulate high acceleration environments. Medium-sized centrifuges are used in washing machines and at some swimming pools to wring water out of fabrics. Gas centrifuges are used for isotope separation, such as to enrich nuclear fuel for fissile isotopes. English military engineer Benjamin Robins invented a whirling arm apparatus to determine drag. In 1864, Antonin Prandtl proposed the idea of a dairy centrifuge to separate cream from milk; the idea was subsequently put into practice by his brother, Alexander Prandtl, who made improvements to his brother's design, exhibited a working butterfat extraction machine in 1875. A centrifuge machine can be described as a machine with a rotating container that applies centrifugal force to its contents. There are multiple types of centrifuge, which can be classified by intended use or by rotor design: Types by rotor design: Fixed-angle centrifuges are designed to hold the sample containers at a constant angle relative to the central axis.
Swinging head centrifuges, in contrast to fixed-angle centrifuges, have a hinge where the sample containers are attached to the central rotor. This allows all of the samples to swing outwards. Continuous tubular centrifuges do not have individual sample vessels and are used for high volume applications. Types by intended use: Laboratory centrifuges, are general-purpose instruments of several types with distinct, but overlapping, capabilities; these include superspeed centrifuges and preparative ultracentrifuges. Analytical ultracentrifuges are designed to perform sedimentation analysis of macromolecules using the principles devised by Theodor Svedberg. Haematocrit centrifuges are used to measure the volume percentage of red blood cells in whole blood. Gas centrifuges, including Zippe-type centrifuges, for isotopic separations in the gas phase. Industrial centrifuges may otherwise be classified according to the type of separation of the high density fraction from the low density one. There are two types of centrifuges: the filtration and sedimentation centrifuges.
For the filtration or the so-called screen centrifuge the drum is perforated and is inserted with a filter, for example a filter cloth, wire mesh or lot screen. The suspension flows through the filter and the drum with the perforated wall from the inside to the outside. In this way the solid material can be removed; the kind of removing depends on the type of centrifuge, for example manually or periodically. Common types are: Screen/scroll centrifuges Pusher centrifuges Peeler centrifuges Inverting filter centrifuges Sliding discharge centrifuges Pendulum centrifugesIn the sedimentation centrifuges the drum is a solid wall; this type of centrifuge is used for the purification of a suspension. For the acceleration of the natural deposition process of suspension the centrifuges use centrifugal force. With so-called overflow centrifuges the suspension is drained off and the liquid is added constantly. Common types are: Pendulum centrifuges. Though most modern centrifuges are electrically powered, a hand-powered variant inspired by the whirligig has been developed for medical applications in developing countries.
A wide variety of laboratory-scale centrifuges are used in chemistry, biology and clinical medicine for isolating and separating suspensions and immiscible liquids. They vary in speed, temperature control, other characteristics. Laboratory centrifuges can accept a range of different fixed-angle and swinging bucket rotors able to carry different numbers of centrifuge tubes and rated for specific maximum speeds. Controls vary from simple electrical timers to programmable models able to control acceleration and deceleration rates, running speeds, temperature regimes. Ultracentrifuges spin the rotors under vacuum, eliminating air resistance and enabling exact temperature control. Zonal rotors and continuous flow systems are capable of handing bulk and larger sample volumes in a laboratory-scale instrument. Another application in laboratories is blood separation. Blood separates into cells and proteins
Ice cream is a sweetened frozen food eaten as a snack or dessert. It may be made from dairy milk or cream, or soy, coconut or almondmilk, is flavored with a sweetener, either sugar or an alternative, any spice, such as cocoa or vanilla. Colourings are added, in addition to stabilizers; the mixture is stirred to incorporate air spaces and cooled below the freezing point of water to prevent detectable ice crystals from forming. The result is a smooth, semi-solid foam, solid at low temperatures, it becomes more malleable as its temperature increases. The meaning of the name "ice cream" varies from one country to another. Terms such as "frozen custard," "frozen yogurt," "sorbet," "gelato," and others are used to distinguish different varieties and styles. In some countries, such as the United States, "ice cream" applies only to a specific variety, most governments regulate the commercial use of the various terms according to the relative quantities of the main ingredients, notably the amount of cream.
Products that do not meet the criteria to be called ice cream are sometimes labelled "frozen dessert" instead. In other countries, such as Italy and Argentina, one word is used for all variants. Analogues made from dairy alternatives, such as goat's or sheep's milk, or milk substitutes, are available for those who are lactose intolerant, allergic to dairy protein, or vegan. Ice cream may be licked from edible cones. Ice cream may be served with other desserts, such as apple pie, or as an ingredient in ice cream floats, milkshakes, ice cream cakes and baked items, such as Baked Alaska. History of ice creams began around 500 BC in the Achaemenid Empire with ice combined with flavors to produce summertime treats. In 400 BC, the Persians invented a special chilled food, made of rose water and vermicelli, served to royalty during summers; the ice was mixed with saffron and various other flavours. During the 5th century BC, ancient Greeks ate snow mixed with honey and fruit in the markets of Athens.
Hippocrates encouraged his Ancient Greek patients to eat ice "as it livens the life-juices and increases the well-being." A frozen mixture of milk and rice was used in China around 200 BC. "They poured a mixture of snow and saltpetre over the exteriors of containers filled with syrup, for, in the same way as salt raises the boiling point of water, it lowers the freezing point to below zero." The Roman Emperor Nero had ice brought from the mountains and combined it with fruit toppings to create chilled delicacies. In the sixteenth century, the Mughal emperors from the Indian subcontinent used relays of horsemen to bring ice from the Hindu Kush to Delhi, where it was used in fruit sorbets. Kulfi is a popular frozen dairy dessert from the Indian subcontinent and is described as "traditional Indian ice cream." It originated in the sixteenth century in the Mughal Empire. When Italian duchess Catherine de' Medici married the Duke of Orléans in 1533, she is said to have brought with her to France some Italian chefs who had recipes for flavoured ices or sorbets.
One hundred years Charles I of England was so impressed by the "frozen snow" that he offered his own ice cream maker a lifetime pension in return for keeping the formula secret, so that ice cream could be a royal prerogative. There is no historical evidence to support these legends, which first appeared during the 19th century; the first recipe in French for flavoured ices appears in 1674, in Nicholas Lemery's Recueil de curiositéz rares et nouvelles de plus admirables effets de la nature. Recipes for sorbetti saw publication in the 1694 edition of Antonio Latini's Lo Scalco alla Moderna. Recipes for flavoured ices begin to appear in François Massialot's Nouvelle Instruction pour les Confitures, les Liqueurs, et les Fruits, starting with the 1692 edition. Massialot's recipes result in a pebbly texture. Latini claims that the results of his recipes should have the fine consistency of snow. Ice cream recipes first appeared in England in the 18th century; the recipe for ice cream was published in Mrs. Mary Eales's Receipts in London in 1718.
To ice cream. Take Tin Ice-Pots, fill them with any Sort of Cream you like, either plain or sweeten’d, or Fruit in it; when you wou’d freeze any Sort of Fruit, either Cherries, Currants, or Strawberries, fill your Tin-Pots with the Fruit, but as hollow as you can. An early reference to ice cream given by the Oxford English Dictionary is from 1744, reprinted in a magazine in 1877. "1744 in Pennsylvania Mag. Hist. & Biogr. I. 126 Among the rarities..was some fine ice cream, with the strawberries and milk, eat most deliciously."The 1751 edition of The Art of Cookery made Plain and Easy by Hannah Glasse features a recipe for ice cream. O
A hydrometer is an instrument used for measuring the relative density of liquids based on the concept of buoyancy. They are calibrated and graduated with one or more scales such as specific gravity. A hydrometer consists of a sealed hollow glass tube with a wider bottom portion for buoyancy, a ballast such as lead or mercury for stability, a narrow stem with graduations for measuring; the liquid to test is poured into a tall container a graduated cylinder, the hydrometer is lowered into the liquid until it floats freely. The point at which the surface of the liquid touches the stem of the hydrometer correlates to relative density. Hydrometers can contain any number of scales along the stem corresponding to properties correlating to the density. Hydrometers are calibrated for different uses, such as a lactometer for measuring the density of milk, a saccharometer for measuring the density of sugar in a liquid, or an alcoholometer for measuring higher levels of alcohol in spirits; the hydrometer makes use of Archimedes' principle: a solid suspended in a fluid is buoyed by a force equal to the weight of the fluid displaced by the submerged part of the suspended solid.
The lower the density of the fluid, the deeper a hydrometer of a given weight sinks. An early description of a hydrometer appears in a letter from Synesius of Cyrene to the Greek scholar Hypatia of Alexandria. In Synesius' fifteenth letter, he requests Hypatia to make a hydrometer for him. Hypatia is given credit for inventing the hydrometer in early 5th century; the instrument in question is a cylindrical tube, which has the shape of a flute and is about the same size. It has notches in a perpendicular line, by means of which we are able to test the weight of the waters. A cone forms a lid at one of the extremities fitted to the tube; the cone and the tube have one base only. This is called the baryllium. Whenever you place the tube in water, it remains erect. You can count the notches at your ease, in this way ascertain the weight of the water. According to the Encyclopedia of the History of Arabic Science, it was used by Abū Rayhān al-Bīrūnī in the 11th century and described by Al-Khazini in the 12th century.
It appeared again in the work of Jacques Alexandre César Charles in the late 18th century, more or less contemporarily with Benjamin Sikes' discovery of the device by which the alcoholic content of a liquid can be automatically determined. The use of the Sikes device was made obligatory by British law in 1818; the hydrometer sinks deeper in low-density liquids such as kerosene and alcohol, less deep in high-density liquids such as brine and acids. It is usual for hydrometers to be used with dense liquids to have the mark 1.000 near the top of the stem, those for use with lighter liquids to have 1.000 near the bottom. In many industries a set of hydrometers is used to have instruments covering the range of specific gravities that may be encountered. Modern hydrometers measure specific gravity but different scales were used in certain industries. Examples include: API gravity, universally used worldwide by the petroleum industry. Baumé scale used in industrial chemistry and pharmacology Brix scale used in fruit juice, wine making and the sugar industry Oechsle scale, used for measuring the density of grape must Plato scale used in brewing Twaddell scale used in the bleaching and dyeing industries Specialized hydrometers are named for their use: a lactometer, for example, is a hydrometer designed for use with dairy products.
They are sometimes referred to by this specific name, sometimes as hydrometers. An alcoholmeter is a hydrometer that indicates the alcoholic strength of liquids which are a mixture of alcohol and water, it is known as a proof and Tralles hydrometer. It measures the density of the fluid. Certain assumptions are made to estimate the amount of alcohol present in the fluid. Alcoholometers have scales marked with volume percents of "potential alcohol", based on a pre-calculated specific gravity. A higher "potential alcohol" reading on this scale is caused by a greater specific gravity, assumed to be caused by the introduction of dissolved sugars. A reading is taken before and after fermentation and approximate alcohol content is determined by subtracting the post fermentation reading from the pre-fermentation reading. A lactometer is used to check purity of cow's milk; the specific gravity of milk does not give a conclusive indication of its composition since milk contains a variety of substances that are either heavier or lighter than water.
Additional tests for fat content are necessary to determine overall composition. The instrument is graduated into a hundred parts. Milk is poured in and allowed to stand until the cream has formed the depth of the cream deposit in degrees determines the quality of the milk. If the milk sample is pure, the lactometer floats. A saccharometer is a hydrometer used for determining the amount of sugar in a solution, invented by Thomas Thomson, it is used by winemakers and brewers, it can be used in making sorbets and ice-creams. The first brewers' saccharometer was constructed by Benjamin Martin, used for brewing by James Baverstock Sr in 1770. Henry Thrale adopted its use and it was popularized by John Richardson in 1784, it consists of a large weighted glass bulb with a thin stem rising from the top with calibrated markings. The