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In industry it is the precursor to the flux used in soldering. The tin- lead solder commonly used in electronics has about 1% rosin as a flux core helping the molten metal flow and making a better connection. Rosin is an ingredient in printing inks, varnishes, glues, medicineSee drugs, medication, and pharmacology for substances that treat patients. This article is about medical practice. Medicine is a branch of health science concerned with restoring and maintaining health and wellness. Broadly, it is the practical science os, chewing gumChewing gum is like confectionery, but it is made to be chewed, not swallowed. Unsweetened ( sugar free) chewing gum stimulates saliva production, and helps to clean the surface of the teeth (even sugary gum may be helpful, since the sugar dissolves out v, soapThis article is about a common cleaning mixture. For other uses of the word Soap, see Soap (disambiguation). Soap is a surfactant cleaning mixture used for personal or minor cleaning. It usually comes in solid moulded form. In the developed world, synthet, paperPaper is a thin, flat material produced by the compression of fibres. The fibers used are usually natural and based upon cellulose. The most common material is wood pulp from pulpwood (largely softwood) trees such as pines, but other vegetable fiber mater sizingSizing is a substance that is applied to fibers during paper manufacture in order to curb their tendency to absorb liquids by capillary action. By doing so, sizing keeps the ink on the surface of the paper where it was intended to remain. In addition, siz, and, in the olden days, sealing waxSealing wax is used to seal envelopes. It is also used to take the impression of seals on important documents. Now mainly used for decorative purposes, it was formerly used to ensure that the contents of the envelope were secure. It was originally made of.

It is also extensively used for its frictionIn physics, friction is the resistive force that occurs when two surfaces travel along each other when forced together. It causes physical deformation and heat buildup. The frictional force is a function of the force pressing the surfaces together and the-increasing capacity. Such uses include rosining the bowIn music, a bow is a device pulled across the strings of a string instrument in order to make them vibrate and emit sound. In vernacular speech the bow is called a fiddlestick . Materials A bow typically consists of a length of wood with some other materis of stringed instruments such as violins or cellos to enhance sound production. For this purpose, extra substances such as gold and silver are added to the rosin for extra friction (and partly for sheer extravagence, as this can make the most expensive cakes cost hundreds of dollars. Gymnasts, weight lifters, and baseball pitchers use a bag of powdered rosin to keep their hands dry and to increase their grip. Ballet slippers are also rubbed in powdered rosin to reduce slipping.

Rosin is a main ingredient of a powder used to polish glass when making optical instruments such as lenses. For instance, amateur telescope makers use a polishing substance made from rosin to polish and shape telescope mirrors and lenses.

Rosin is also known as colophony or colophonia resina from its origin in Colophon, an ancient Ionic city. It is the resinous constituent of the oleo-resin exuded by various species of pine, known in commerce as crude turpentine. The separation of the oleo-resin into the essential oil-spirit of turpentine and common rosin is effected by distillation in large copper stills. The essential oil is carried off at a temperature of between 100° and 160° C, leaving fluid rosin, which is run off through a tap at the bottom of the still, and purified by passing through straining wadding. Rosin varies in color, according to the age of the tree whence the turpentine is drawn and the amount of heat applied in distillation, from an opaque almost pitchy black substance through grades of brown and yellow to an almost perfectly transparent colorless glassy mass. The commercial grades are numerous, ranging by letters from A, the darkest, to N, extra pale, superior to which are W, window glass, and WW, water white varieties, the latter having about three times the value of the common qualities.

Rosin is a brittle and friable resin, with a faint piny odor; the melting-point varies with different specimens, some being semi-fluid at the temperature of boiling water, while others melt at 100° to 120° C. It is very flammable, burning with a smoky flame, so care should be taken when melting it. When melted to a thick fluid, it can be surprisingly ductile. It is soluble in alcohol, ether, benzene and chloroform. Rosin consists mainly of abietic acid, and combines with caustic alkalis to form salts (rosinates or pinates) that are known as rosin soaps. In addition to its extensive use in soap-making, rosin is largely employed in making inferior varnishes, sealing-wax and various adhesives. It is also used for preparing shoemakers' wax, as a flux for soldering metals, for pitching lager beer casks, for rosining the bows of musical instruments and numerous minor purposes.

In pharmaceuticals it forms an ingredient in several plasters and ointments. On a large scale it is treated by destructive distillation for the production of rosin spirit, pinoline and rosin oil. The last enters into the composition of some of the solid lubricating greases, and is also used as an adulterant of other oils.

The chief region of rosin production is the South Atlantic and Eastern Gulf states of the United States. American rosin is obtained from the turpentine of Longleaf Pine Pinus palustris and Loblolly Pine P. taeda. The main source of supply in Europe is the French district of Les Landes in the departments of Gironde and Landes, where the Maritime Pine P. pinaster is extensively cultivated. In the north of Europe rosin is obtained from the Scots Pine P. sylvestris, and throughout European countries local supplies are obtained from other species of pine, with Aleppo Pine P. halepensis being particularly important in the Mediterranean region.