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Tag: Chemistry
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Deadly Adulteration and Slow Poisoning Unmasked; Or, Disease and Death in the Pot and the Bottle; In Which the Blood-Empoisoning and Life-Destroying Adulterations of Wines, Spirits, Beer, Bread, Flour, Tea, Sugar, Spices, Cheese-Mongery, Pastry, Confectio
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Experiments and Observations on Different Kinds of Air
By the late eighteenth century, scientists had discovered certain types of gas, such as 'fixed air' (carbon dioxide), but their composition was little understood. Relatively few investigations into gases had taken place, and so the polymath Joseph Priestley (1733-1804) was able to make major breakthroughs in the field using a range of experimental techniques. While living near a brewery, he found that it was possible to outline the shape of the gas above fermenting beer with smoke, and that fire would burn with varying strength depending on the composition of the air. This three-volume collection first appeared between 1774 and 1777. Following the international interest and new discoveries prompted by the publication of its predecessor, Volume 2 - reissued here in its corrected 1776 second edition - includes accounts of further experiments, Priestley's paper on the conducting power of charcoal, and, most significantly, notes on what he calls 'dephlogisticated air' (oxygen).
Experiments and Observations on Different Kinds of Air
Joseph Priestley, FRS was an 18th-century English theologian, Dissenting clergyman, natural philosopher, chemist, educator, and political theorist who published over 150 works. In ?Experiments and Observations on Different Kinds of Air,? he reviews experiments with gases. A common theme in this work is measuring the volumes of gases held in glass tubes, and their increase or decrease when exposed to other substances. He also tests the effects of gases on mice, plants and insects. Priestley demonstrated that fixed air (now known as CO2) can be produced from several reactions including alcoholic fermentation, combustion and a mixture of oil of vitriol and chalk (sulfuric acid and calcium oxide). He also showed that it is soluble in water, and that its toxic effects can be reduced when agitated in water. In other experiments, he showed that combinations of gases can mix to form a smaller volume than the sum of both separate gases, as when he combined common air (atmospheric air) with nitrous air (nitric oxide, NO). For some experiments, Priestley tests whether the properties of gases change when stored. He finds that inflammable air (hydrogen, H2 or a mixture of hydrocarbons) becomes less flammable but retains its toxic properties. Also interested in electricity, Priestley tests the effects of gases on sparks. While he finds that gases are generally good insulators, he also finds that some gases change the colors of electric sparks. He also discovers that some mixtures of air explode in their entirety, while others must be combined with common air in order to burn. Priestley uses several terms common to the study of natural philosophy, or chemical experiments as known today. Some of the terms are parts of obsolete theories or are old names for chemicals now given standard names. To better understand Priestley's observations, the following terms are defined according to their present names. here
Familiar Letters on Chemistry
Justus von Liebig (1803-1873) was a German chemist who made major contributions to agricultural and biological chemistry and is known for his discovery of nitrogen as an essential plant nutrient. These letters ?were written for the especial purpose of exciting the attention of governments, and an enlightened public, to the necessity of establishing Schools of Chemistry, and of promoting by every means, the study of a science so intimately connected with the arts, pursuits, and social well-being of modern civilised nations.? (Summary by Wikipedia and J.M. Smallheer)