LEONARDO DA VINCI: Fire consumes air.

ECK VON SULZBACH: First notes an increase in weight of metals on calcination. (ca. 1490)

1500 {contemporary people, events and developments}     {Return to top}

The TRIA PRIMA of PARACELSUS; all matter consists of

mercury --- fusibility, volatility, liquidity.
sulphur (hereafter written "sulfur") --- combustibility.
salt -- non-combustibility, involatility.

PARACELSUS is the first to describe zinc.

CARDANUS attributes gain in weight on calcination to loss of celestial fire (1553)

DANIEL SENNERT substituted water (in the TRIA PRIMA) for mercury.

• laid the foundations of chemical physiology, especially relation of acids and alkalies to digestion, etc.
• distinguished different "kinds" of air.
• originated the word "gas."

JEAN REY: Increase in weight of calx due to air absorbed by the metal, just as water is absorbed by a solid. (1630)

"The first chemist whose efforts are employed primarily in the noble impulse to investigate nature." ---- Koop

• 1660: SPRING AND WEIGHT OF AIR"
• Improved air pump.
• BOYLE'S LAW.
• Showed relation between combustion and respiration in air-pump experiments.
• 1661: "SCEPTICAL CHYMIST."
  
  Atomic theory of EPICURUS (341-270 B.C.) rejuvenated (by, among others ROBERT HOOKE).

  Atoms of different sizes and shapes.

  Opposes Aristotelian and Paracelsan ideas of elements, introducing the modern concept:

  "Certain Primitive and Single, or perfectly unmingled bodies which not being made of any other bodies, or of one another, are the ingredients of which all those called perfectly mixed bodies are immediately compounded."

  But no known substance is such an element.
  

  Distinction between compounds and mixtures.
  
  

  ROBERT BOYLE's experiments on "ponderable fire particles" (1673) led to the idea by

  JOHANN J. BECHER and NICHOLAS LEMERY that combustion and calcination are due to a "fire substance."

  Further work by Boyle: "SUSPICIONS ABOUT SOME HIDDEN QUALITIES OF AIR" includes:

  "There may be dispersed through the rest of the atmosphere some odd substance on whose account the air is so necessary to the substance of flame."

  Relation of air to combustion becomes more evident.
  

  Combustion ascribed to a "nitrous" constituent of air---25% by volume.

  NEWTON explains "BOYLE'S LAW" by repulsion of atoms.

  HOOKE and WILLIS suggest that

  • burning of sulfurous (i.e., combustible) bodies is due to the action of a substance in air similar to that which is fixed in saltpeter, and
  • there is no "fire-element".

  MAYOW, building on the above ideas of Boyle, Hooke, and Willis: relation of air to combustion becomes more evident. Combustion is ascribed to a "nitrous" constituent of air---25% by volume. In his "DE RESPIRATIONE" and "DE SAL-NITRO", Mayow recognized the relation between respiration and combustion.

  "For burning of things it is necessary that nitro-aerial particles should either be already in the burning mass or be supplied from the air."

  BECHER in his "PHYSICAE SUBTERRANEAE" (1669)

  attributes "earthy" nature to all of PARACELSUS's TRIA PRIMA,renaming them

  terra prima (fusible)
  terra secunda or terra pinguis (combustible), and
  terra tertia (fluid)

  G. E. STAHL (1697) in his "ZYMOTECHNIA FUNDAMENTALS" conceives PHLOGISTON (=TERRA PINGUIS) to be a single principle. Burning of sulfur and other substances is analogous to calcination of metals (that is, it involves loss of phlogiston). On heating the calx with carbon or other substances containing phlogiston, the calx recombines with the phlogiston, reducing the original metal. Phlogiston has negative weight, hence the calx weighs more than the metal. (By the early 1700's, Stahl himself came to doubt Phlogiston.)

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  1700 {contemporary people, events and developments}     {Return to top}

  Convinced phlogistonists included:

  • William Homberg
  • Casper Neumann
  • René de Réamur
  • Johann Juncker
  • Johann T. Eller
  • Johann H. Pott
  • G. F. Rouelle
  • Pierre Joseph Macquer
  • Torbern Olaf Bergman

  GEOFFROY (1718): first serious attempt to tabulate chemical affinities.

  STEPHEN HALES:

  • 1727: "VEGETABLE STATICKS"
  • 1733: "STATICAL ESSAYS"
  • Quantitative studies of the amounts of various gases ("air") given off in miscellaneous reactions. Did not distinguish between different gases.

  ABBÉ NOLLET (1748): first osmotic experiments.

  Rejection of Phlogiston Theory

  HOFFMAN and BOERHAAVE ("anti-phlogistic converts") reject the analogy between combustion and calcination, leading to the ultimate downfall of the Phlogiston Theory.

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  1750 {contemporary people, events, and developments}     {Return to top}

  MIKHAIL V. LOMONOSOV

  1741: "ELEMENTS OF MATHEMATICAL CHEMISTRY." Atomic and molecular constitution of bodies.

  1744: "CAUSES OF HEAT AND COLD." Kinetic-molecular theory. Heat = molecular motion.

  1750: Explanation of Boyle's Law and deviations from it on basis of kinetic theory.

  1756: increase in weight of calx is at the expense of air. Rejects Phlogiston Theory.
  
  JOSEPH BLACK (1752-4):
  

  relation of "fixed air" to mild and caustic alkalies.

  experiments on heat transfer "caloric"
  
  Work of BLACK, MACBRIDE, et al., shows relation of CO₂ to fermentation and putrefaction.
  
  MACBRIDE (1764): "EXPERIMENTAL ESSAYS." "Fixed air" causes cohesion in bodies.
  
  D. RUTHERFORD --- Nitrogen.
  
  

  HENRY CAVENDISH: "EXPERIMENTS ON FACTITIOUS AIR.": experimented with inflammable air (H₂) from metals plus acids.
  

  Terminology during Cavendish's time:
  

  Dephlogisticated air = water - phlogiston
  

  Inflammable air = water + phlogiston
  

  Dephlogisticated air + inflammable air = water 1771-1777: SCHEELE

  • prepared (?) "aer vitriolicus" ( = O₂ )
  • investigated "black magnesia"
  • Dephlogisticated marine acid (Cl₂)
  • described hydrofluoric acid
  • 1777: "CHEMISCHE ABHANDLUNG VON DER LUFT UND DEM FEUER." Investigation of the composition of air.
    
    Prepared "fire-air" by heating various substances. Recognized it as the combustible part of the air.
    
    ( "Fire-air + phlogiston = heat ")

  1771: PRIESTLEY: Transpiring plants give off "dephlogisticated air."
  1772: Soda water introduced by PRIESTLEY.
  
  ANTOINE LAURENT LAVOISIER:
  

  1770: Water does not change into earth.

  1774: "OPUSCULES PHYSIQUES ET CHYMIQUES."

  1774: Calcined metals increase in weight at the expense of air.

  1775: "COMPOSITION OF AIR."

  "The principle which combines with metals during calcination and which augments the weight of them is no other than that more pure portion...which we breathe." "Fixed air is the result of the combination of the eminently respirable portion of the air with the carbon." ( new theory of combustion)

  1777: "NATURE OF ACIDS."

  The "more pure air" (O₂) = constituent of all acids (hence the name "oxygen" which means "acid former.")

  1783: "REFLEXIONS SUR LE PHLOGISTIQUE." which built upon the thought of Cavendish (see above). DEATH BLOW TO PHLOGISTON THEORY.

  "METHODE DE NOMENCLATURE CHIMIQUE,"

  LAVOISIER, BERTHOLLET, DE MORVEAU, and DE FOURCROY.

  Foundation for development of systematic chemistry.

  LAVOISIER: First to recognize the common elementary constituents of organic substances and to devise methods for their determination.
  
  

  1789: "TRAITÉ ELÉMENTAIRE DE CHEMIE."

  The "TRAITÉ" was a complete and detailed exposition of LAVOISIER'S new system of chemistry; it was a truly modern text and it laid the foundations of modern chemistry. The "TRAITÉ" included a table of 33 simple substances or elements---another milepost of modern chemistry.

  Alchemy as a practical art dies with the advent of
  

  the New Chemistry following LAVOISIER.
  
  

  From the time of LAVOISIER biological chemistry begins to become a distinct and separate branch of the science. Previously, the iatrochemical influence caused a considerable identity of interest between the physical and the biological sciences.
  
  

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  Post-1800 developments in:
  

  General, Analytical and Physical Chemistry       Organic and Biochemistry   
  

  Discovery of Elements and Contemporary Events