Elements of chemistry / by Thomas Thomson, M.D.

  • Thomson, Thomas, 1773-1852.
Date:
1810
Catalogue details

Licence: Public Domain Mark

Credit: Elements of chemistry / by Thomas Thomson, M.D. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    more abundant the higher the temperature, and is occasioned by the gradual combustion of the phosphorus. In oxygen gas it is not luminous unless the temperature be as high as 80°. Hence we learn that it burns at a lower temperature in common air than in oxygen gas. This slow combustion in the open air renders it necessary to keep phosphorus in phials filled with wa- ter and well corked. When heated to 148° it takes fire and burns with a vivid white flame and emitting a vast quantity of smoke. It leaves (if pure) no residuum, but the white smoke when collected is an acid, and is called phosphoric acid. If the combustion be conducted in a jar filled with oxygen gas, the oxygen will be found to diminish so much, that every one hundred parts of phosphorus occasion the disappearing of one hundred and four- teen parts of oxygen. The acid formed weighs as much as the phosphorus and the oxygen which have disappeared. Hence it is considered as a compound of these two in the proportion of one hundred parts of phosphorus to one hundred and four- teen of oxygen. Phosphorus is supposed capable of combining with a small portion of oxygen and of forming a compound called oxide of phosphorus. It may be formed by putting a bit of phosphorus in a long glass tube and exposing it to tiie heat of boiling water. It sublimes and lines the tube in fine white flakes. This sub- stance is very combustible and often takes fire of its own ac- cord when exposed to the air. When melted by means of a burning glass in hydrogen gas, a portion of it is dissolved, and a new gas formed, first disco- vered by Gemgembre, and called phosphureted hydrogen gas. It has a fetid odour like the smell of putrid fish. It barns spon- taneously when it comes into contact with common ;>ir or oxy- gen gas. Water dissolves a small portion of this gas and ac- quires a bitter taste and unpleasant odour. The phosphorus gradually precipitates, and the hydrogen at the same time se- parates from the water. When kept in a glass jar it soon loses its property of burning spontaneously. Phosphorus combines with charcoal and forms a compound of an orange red colour called phosphuret of carbon. Com- mon phosphorus contains a portion of this compound which re- mains behind when the phosphorus is burnt. It is a light flocky powder without taste or smell. When heated sufficiently it • bu:',!;, and the charcoal remains behind. The compounds which phosph rus forms with other bodies are distinguished by the name of phosph Phosphorus is very poisonoui :l internally. It has been recommended as a medicine, and said to be very effica-