Background

Andreas Sigismund Marggraf was born on March 3, 1709, in Berlin, Germany to the family of the pharmacist Henning Christian Marggraf and Anne Kellner. The influence of his mother remains obscure; but it is known that his father, apothecary to the royal court at Berlin and assessor (assistant) at the Collegium Medico-Chirurgicum, introduced him to a circle of pharmacists and chemists.

Education

Andreas Sigismund Marggraf started studying at the medical school in 1725. He studied with Caspar Neumann in Berlin, Germany but he also visited pharmacies in other cities, including Frankfurt am Main and Strassbourg. He also attended lectures at the University of Halle. Andreas Marggraf received a well-rounded training in chemistry that began with his father's various connections.

Andreas Marggraf studied mainly under his father’s colleagues but also visited many pharmacies in many cities. From 1730 to 1733, he assisted the apothecary Rossler in Frankfurt-am-Main and studied with the chemist Spielmann the elder at the University of Strasbourg; in 1733 at Halle he heard the lectures of Friendrich Hoffmann in medicine and of Johann Juncker in chemistry; in 1734 he traveled to Freiberg, Saxony, to study metallurgy with Henckel.

Career

After two years with his father in the Berlin court pharmacy Marggraf visited Wolfenbüttel, Brunswick, in 1737 but he refused an offer of the post of the ducal apothecary. He chose to return to Berlin, where he was admitted the following year to the Königlick Presussischen Societät der Wissenschaften (reorganized in 1744-1746 as the Académie Royale des Sciences et Belles-Letters). Despite the recriminations of a senior academician, J. H. Pott, Frederick II selected A. Marggraf as director of the Academy’s chemical laboratory in 1753 and as director of its Class of Experimental Philosophy in 1760.

Marggraf was also a member of the Kurakademie der Nützlichen Wissenschaften of Mainz and a foreign associate of the Paris Academy of Sciences (1777). Although unable to write after suffering a stroke in 1774, he confounded attempts to replace him and prepared studies for publication until 1781. Marggraf introduced several new methods into experimental chemistry. He used precipitation methods for analysis, like the Prussian blue reaction for the detection of iron. Marggraf's major work in inorganic chemistry included the improved production of phosphorus from urine and the detection of alkali metal salts in plant ash and their identification by flame test.

Marggraf extraction of sugar from beets, which was then only available from sugarcane, was the starting point for the sugar industry in Europe. Although Marggraf recognized the economic impact of that discovery, he did not pursue it. The Marggraf's student Franz Achard, completed the work and developed an economic extraction method for sugar from sugar beet. He also was the first to isolate glucose from raisins in 1747.

Marggraf had isolated zinc in 1746 by heating a mixture of calamine and carbon in a closed vessel without copper. He was unaware that the same process had been developed (and patented) by William Champion in England around 1738-1740 and by Anton von Swab in Sweden around 1742. A. Marggraf, however, had described the process in great detail and established its basic theory, for which he is often credited with the isolation of zinc. This procedure became commercially practical by 1752.

In 1750 Marggraf noted that the earth contained in "Bologna stone" (barium sulfide), another phosphorescent substance, is heavier and more soluble than lime. In the same memoir, he anticipated Lavoisier’s conclusions by identifying the constituents of gypsum as water, lime, and vitriolic acid.

Marggraf’s innovations in analytical methods included an emphasis on "wet methods", or solvent extraction, with careful attention to washing and recrystallization of the end product. His work with certain organic substances, for example, the acid extracted from ants (1749) and the "essential oil" of cedar shavings (1753), combined traditional destructive distillation with the sophisticated use of solvents later practiced by G. F. Rouelle. Marggraf’s most significant contribution to applied chemistry was his extraction and crystallization of sugar from plants commonly grown in Europe. In 1747 he used boiling rectified alcohol to extract the juice from the dried roots of Beta alba (white mangel-wurzel), Sium sisarum (skirret), and Beta radicae rapae (red mangel-wurzl). When crystals appeared several weeks later, he confirmed their identity with those of cane sugar by microscopic observation-perhaps the first such use of the microscope in the chemical laboratory.

Marggraf became the director of the chemical laboratory of the German Academy of Sciences of Berlin and worked from 1754 to 1760. Marggraf became director of the physical class at the Academy of Sciences in 1760. During this time, he also gave private instruction in chemistry. He was the first to use a microscope in the field of chemistry.

In 1759, to distinguish "cubic niter" (sodium nitrate) from "prismatic niter" (potassium nitrate) crystals, Marggraf used, besides the microscope, the flame test-forerunner of modern emission spectroscopy-which differentiated the violet flash of ignition of saltpeter from the yellowish flash of the sodium nitrate. The blowpipe, a tube designed to intensify the flame by directing air upon it, refined this test to reveal characteristic colors and products upon the fusion of metal.

The most notable of Marggraf’s isolations of mineral substances were his production of the "acid of phosphorus" and his improved preparation of phosphorus itself. In 1740 he obtained white "flowers" (oxide of phosphorus) from the combustion of phosphorus and recorded, without explanation, the phenomenon so crucial to Lavoisier in 1772, that the calx showed an increase in weight. More remarkable to Marggraf was the hydration of the product in the air to form the previously unknown oily phosphoric acid. When heated with coal this acid yielded, in Marggraf’s terms, phlogiston and phosphorus.

Achievements

• Andreas Marggraf discovered beet sugar in the year 1747 which led to the development of the modern sugar industry. He distinguished between the oxides of aluminum (alumina) and calcium (lime) found in common clay, and he simplified the process for obtaining phosphorus from urine.

Works

More photos

• book

  • Einige neue Methoden, den Phosphor im festen Zustande sowohl leichter als bisher aus dem Urin darzustellen als auch denselben bequem und rein aus brennbarer Materie (Phlogiston) und einem eigentümlichen, aus dem Urin abzuscheidenden Salze zu gewinnenAndreas Sigismund Marggraf Andreas Sigismund Marggraf 1743
  • Opuscules Chymiques De M. Margraf: Tome I 1747
  • Opuscules Chymiques De M. Margraf I 1762
  • Opuscules Chymiques De M. Margraf: Tome II 1762
  • Chymische Schriften, Volume 2 1761

Views

For Marggraf his work and learning were a major concern and he focused on them only other than any other things which would divert his mind from work.

Membership

• Prussian Academy of Sciences , Germany

  1738

• 

  Academy of Sciences and Literature , Germany

• 

  French Academy of Sciences , France

Personality

Andreas Marggraf was a modest, even-tempered man of precarious health but of single-minded devotion to study and laboratory experimentation. Focusing always on his experiments and developments made him known in the world.

Interests

• research

Connections

There is no information on whether Andreas Sigismund Marggraf was ever married or had any children.

Father:

Henning Christian Marggraf

Mother:

Anne Kellner

pupil:

Franz Achard

References

• Dictionary of Scientific Biography: Volumes 9 & 10
  1980