Fresenius, Carl Remigius

(b. Frankfurt am Main, Germany, 20 December 1818; d. Wiesbaden, Germany, 11 June 1897)

analytical chemistry.

Fresenius’ father, Jakob Heinrich Fresenius, was a notary; his mother was Maria Veronika Finger. Until the Thirty Years’ War most of his male ancestors had been Protestant ministers. After attending elementary and secondary school in Frankfurt and in Weinheim, Fresenius was apprenticed to an apothecary. He frequently attended the public science lectures at the Physical Society and other institutions, and in 1840 he entered the University of Bonn, where he studied science, history, and philosophy. In those days very few institutions of higher learning afforded any opportunity for practical experimentation. Bonn was not one of them, so Fresenius tested his newly acquired knowledge in the private laboratory of Ludwig Marquart. The principal aim of his experiments was identification of the different elements through qualitative analysis by the wet method.

When Fresenius began to conduct his own laboratory experiments with qualitative reactions, he was faced with a problem then doubtless confronting all young chemists: the lack of any guidelines for systematic qualitative analysis or any coherent sources from which the art could be learned. Older books on analytical chemistry dealt with the subject only from the standpoint of elements, which they listed in the order of their behavior in the presence of various reagents, but gave no systematic methods for identifying the constituents of a mixture of unknown substances. He therefore devised a method of his own for systematic identification and separation of the individual metals (cations) and nonmetals (anions), selecting from the great multitude of reactions those which struck him as most suitable. His system worked so well that, at Marquart’s suggestion, he expanded it into a book, published in 1841 under the title Anleitung zur qualitativen chemischem Analyse.

By this time Fresenius was in Giessen to continue his chemical studies under the direction of Justus Liebig. In addition to Liebig’s lectures, he attended those of Heinrich Buff and Hermann Kopp. The second edition of his Anleitung, with a preface by Liebig, appeared in 1842. It states that as early as 1841 inorganic analytical chemistry was being done according to the Fresenius text in Liebig’s laboratory. The book gained Fresenius his doctorate on 23 July 1842, and Liebig made him his assistant. The book was an unprecedented success. A third edition was published in 1844 and a fourth in 1846. In a period of twenty years there were eleven German editions. By the time of Fresenius’ death seventeen had appeared, each an improved and expanded version of the preceding one, incorporating the latest knowledge and results. The book was soon translated into English, French, Italian, Dutch, Russian, Spanish, Hungarian, and Chinese. The first English edition, translated by J. Lloyd Bullock, appeared in 1841 under the title Elementary Instruction in Qualitative Analysis. Eight English editions were published. This enormous success clearly shows the magnitude of the gap in scientific knowledge which the Fresenius system of qualitative analysis filled. The system was taught for a century in all colleges and universities, and while qualitative analysis by the wet method on a macroscopic scale has lost much of its practical importance in recent times, it is still regarded as a valuable instruction tool and continues to be taught in many places.

The Fresenius system is oviously based on Heinrich Rose’s separation method. Fresenius divided the cations (or metal oxides, as they were then called under Berzelius’ dualistic theory) into six groups. Classed in the same group are cations that behave in the same way (precipitate or, less frequently, dissolve) in the presence of a given reagent under specific experimental conditions. The basic reagent used was hydrogen sulfide; the determining property, the behavior of the various metallic sulfides in different situations. The breakdown was as follows:

Group 6—metals which form a precipitate with hydrogen sulfide in acid or alkaline solution: mercury (+ 1, + 2), lead, bismuth, silver, copper, and cadmium. Silver, mercury (+ 1), and lead are precipitable with hydrochloric acid.

Group 5—gold, platinum, antimony, tin (+ 4, + 2), arsenic (+ 3, + 5), whose sulfides are soluble in ammonium sulfide.

Group 4— metals whose sulfides are precipitable only in alkaline or neutral solution: zinc, manganese, nickel, cobalt, and iron (+ 3, + 2).

Group 3—metals whose sulfides are soluble and whose hydroxides are precipitable with ammonium sulfide: aluminum and chromium.

Group 2—metals whose sulfides are soluble and are precipitated with alkali carbonates and alkali phosphates: barium, strontium, calcium, and magnesium.

Group 1—both the sulfides and carbonates are soluble: sodium, potassium, and ammonium.

This classification matches exactly the one still in use today, except that Groups 4 and 3 were subsequently merged and the numeration was reversed, Fresenius’ Group 6 becoming Class 1, etc. Fresenius did not content himself with the separation into groups but, through treatment with other suitable reagents, broke down each group into its individual member elements. He never used the blowpipe. The number of reagents that he employed was relatively small, which made his system simple and easy to learn.

Fresenius married his cousin Charlotte Rumpf in 1845. They had four daughters and three sons, two of whom, Heinrich and Wilhelm, became chemists and continued operation of the Fresenius Training and Research Institute and publication of the Zeitschrift für analytische Chemie. After more than twenty-five years of marriage Fresenius’ wife died, and Fresenius married Auguste Fritze, a friend of his deceased wife.

In 1845 the Wiesbaden Agricultural College in the duchy of Nassau offered Fresenius a position as professor of chemistry, physics, and engineering. He accepted and moved to Wiesbaden. The college was very poorly equipped, and Fresenius had no laboratory for teaching or for his own experimental work. He decided to establish one. With a modest subsidy from the duchy, he bought a building and equipped it. This laboratory, which opened in 1848, served several purposes. It offered training in practical chemistry, especially analytic procedures. When it opened, five students started work there under the direction of an instructor, Emil Erlenmeyer, later professor of chemistry at the University of Munich. By 1854–1855 there were thirty-eight students and three instructors. A school of pharmacy was subsequently added. The duchy of Nassau allowed college credit for study at Fresenius’ laboratory, but this was discontinued after Nassau was annexed to Prussia. The laboratory then switched to training food chemists and public health personnel. As the role of practical education began to increase at the universities, the laboratory turned more and more to the training of laboratory technicians. It also conducted analyses for industry, soon acquiring an international reputation in this field. Its arbitrational analyses settled many disputes in foreign countries. Fresenius ran the enterprise until his death, and his research institute still operates under the direction of the Fresenius family.

In 1845 Fresenius also published his Anleitung zur quantitativen chemischen Analyse. Although this book had had six printings by the time of his death, it is of less importance than his work on qualitative analysis. After describing the analytic operations, the book discusses the forms in which the individual elements can be determined. It then deals with the separations but fails to offer any particularly coherent system (which so far no one else has done). It is also noteworthy that the book does describe many examples of indirect analysis. In many places, too, Fresenius’ book touches upon the thermal behavior of analytic precipitates, indicating their thermal stability and discussing the nature of thermal decomposition processes. He can therefore rightly be regarded as one of the pioneers of thermal analysis.

In 1862 Fresenius founded the journal Zeitschrift für analytische Chemie. The earliest chemical journals date from the last two decades of the eighteenth century. For almost a century, though, there was no differentiation within the general field of chemistry. The founding of the Zeitschrift für analytische Chemie marked the beginning of specialization.

In a special announcement, Fresenius explained his intention in publishing the journal:

It is readily provable that all great advances in chemistry have been more or less directly related to new or improved analytic methods. The first usable procedures for analyzing the salts were followed by our discovery of the stoichiometric relationships; the progress in analysis of inorganic substances yielded ever more precise equivalent weights; the methods for exact determination of the elements in organic substances gave unexpected impetus to the development of organic chemistry. . . . In truth, therefore, our methods of analysis represent a great achievement in themselves, an important scientific treasure.

The nature of an independent science of analytical chemistry was thus proclaimed. The journal, consisting of original writings on all aspects of analytical chemistry and of systematically arranged reports, still appears regularly. Fresenius himself published many papers on the results of his experimental research. While all of them were scientifically precise, they dealt mostly with special cases and, as regards methodology, contained nothing remotely comparable in significance to his qualitative system. He reported his analyses of numerous mineral waters and explored in detail the possible analytic uses of potassium cyanide; and he was concerned with the detection and quantitative determination of arsenic in cases of poisoning and with the testing of potash, soda, acids, and pyrolusite. He reported also on the determination of nitric acid, lithium, a great many metal alloys, sulfuric acid, metal ores, and boric acid, and the separation of the salts of the alkaline earth metals. Most of those studies consisted of experimental and critical testing of existing methods and of selection of the most favorable operating conditions rather than of a quest for new methods and forms of analysis. To render the analytic process more precise and refine its methods, Fresenius determined the solubility of many analytic precipitates and, on the basis of those tests, recommended correction values for analytic calculations. He also engaged in food research, primarily in analysis of fruit and wine.

Fresenius was active in that period when analytical chemistry was serving not only to increase man’s knowledge of the constituents of his environment but also was being increasingly used for day-to-day control of industrial products. Analytic laboratories became the natural and indispensable adjuncts of factories in which chemical analyses were an everyday routine. These laboratories required trained personnel, reliable and fast analytic techniques, and an expedient way to prepare information for the analytical literature. Fresenius recognized that chemical analysis had ceased to be a scholarly preoccupation of the few and had become the daily occupation of the many, and he made it his job to help satisfy those needs. This was the aim of his school, his analytic research institute, and his journal. Even most of his own scientific writings were oriented toward the practical and the industrial. This, in fact, was his second greatest accomplishment: he played a large role in shaping the science of chemical analysis to meet the requirements of an industrial age.

Fresenius’ work gained him public recognition, and many honors were bestowed upon him. He was several times president of the Versammlung Deutscher Naturforscher und Ärzte and honorary member of the Gesellschaft Deutscher Chemiker. Contemporaries characterized him as a deeply religious man, with an excellent sense of humor, and an exemplary father. He loved hunting. In 1961 the Gesellschaft Deutscher Chemiker established a Fresenius Prize for outstanding achievement in the field of analytical chemistry.

BIBLIOGRAPHY

I. Original Works. Fresenius’ writings include Anleitung zur qualitativen chemischen Analyse (Bonn, 1841; 2nd-17th eds., Brunswick, 1842–1896); Anleitung zur quantilativen chemischen Analyse (Brunswick, 1845; 2nd-6th eds., 1847–1887); many of his chief analytical works were published in Justus Liebigs Annalen der Chemie and in Zeitschrift für analytische Chemie and are listed in Poggendorff.

II. Secondary Literature. Works on Fresenius are E. Fischer, “Carl Remigius Fresenius,” in Zeitschrift für angewandte Chemie, 10 (1897), 520; H. Fresenius, “Zur Erinnerung an Remigius Fresenius,” in Zeitschrift für analytische Chemie, 36 (1897), 10; R. Fresenius, “Fresenius, Carl Remigius (1818–1897),” in Nassauisech Lebensbilder, vol. I (Wiesbaden, 1940); W. Fresenius, “Remigius Fresenius,” in Zeitschrift für analytische Chemie, 192 (1963), 3; A. J. Ihde, The Development of Modern Chemistry (New York–London, 1964), pp. 278–280; F. Szabadvéry, History of Analytical Chemistry (New York–Oxford, 1966), pp. 161–172, 176–181; and Geschichte der analytischen Chemie (Brunswick, 1966), pp. 185–192, 196–200.

Ferenc SzabadvÁry