Lovits (Lowitz), Johann Tobias

Updated About encyclopedia.com content Print Article Share Article
views updated

Lovits (Lowitz), Johann Tobias

(in Russian, Tovy Yegorovieh )

(b. Göttingen, Germany, 25 April 1757; d, St Petersburg, Russia, 17 December 1804)

chemistry.

Lovits’ mother died when he was very young; his father was Georg Moritz Lovits, a cartographer and instrument maker, who was also, from 1762, a professor at Göttingen University. In 1768 father and son went to St. Petersburg and thence on an ill-fated expedition to the Caspian steppes. The elder Lovits was executed there by the Cossack revolutionary Pugachev, and in 1774, following that event, his orphaned son was placed in the Academy Gymnasium in St. Petersburg. Lovits left the Gymnasium after two years and entered the main pharmacy of St. Petersburg as a student. By 1779 he had become a journeyman pharmacist, and the following year he was sent to Gottingen to continue his education. His health had been precarious throughout his school years, and his university career was interrupted by a serious illness. He attempted to regain his strength by a long foot trip throughout Europe, and succeeded so well that by 1784 he was able to return to St. Petersburg, and to his studies at the main pharmacy there. The study of chemistry by that time occupied all his free time. In 1787 Lovits was made court apothecary; in 1790 he was elected an adjunct, and in 1793 a full member of the St. Petersburg Academy of Sciences.

Lovits became known as a talented and inventive experimenter. In 1785, while trying to obtain a crystalline form of tartaric acid, he noticed that powdered charcoal which accidentally contaminated the acid solution effectively removed visible impurities. He thus began his research on adsorption, at first attributing the adsorptive qualities of charcoal to its “dephlogistic action.” He set up an extensive program to test the effects of charcoal on a number of different substances, employing carbons of wood, bone, and even pure tartaric acid. Having discovered the efficacy of charcoal for removing color from organic products, he recommended that it be used as a purifying agent for vodka, sugar syrup, and drinking water. He made further investigations of gas adsorption by charcoal, and noted its deodorizing action. In the 1790’s, Lovits adapted Lavoisier’s theory and explained the phenomenon of adsorption chemically (unlike Klaproth and Green, who remained committed to a mechanical interpretation).

Lovits did further research in the crystallization of substances from solutions, introducing the concepts of supercooling and supersaturation. He obtained the crystal hydrates NaCI · 2H2O and KOH · 2H2O, and distinguished between forced crystallization and spontaneous crystallization, noting that the same substance could thus yield crystals of different form and composition. He explained the role of seeding in crystal growth, and used this method to obtain Rochelle salt crystals “of unusual size” from hot, lightly saturated solutions. He further employed the seeding technique to separate the crystal forms of salts, which he used in a number of chemical analyses. Lovits was the first to describe convection currents in the crystallization process. He also developed several formulas for cooling mixtures; fabricated 288 wax models of crystals; and used a microscope to observe the crystalline patterns left on glass after evaporation of the mother solution (thereby laying the foundations of microchemical analysis).

In analytical chemistry Lovits investigated strontium, chrome, titanium, manganese, columbium (niobium), and their salts. Independently of A. Crawford, he isolated strontium from barite, examined the properties of its salts in detail, and developed a method of distinguishing it from barium and calcium according to its solubility in alcohol. Independently of Vauquelin, Lovits, in 1798, derived chrome from Siberian lead ore and established its crystalline form.

Lovits designed new methods to use in his analytical work. He dissolved silicates in heated caustic alkalies, instead of melting them, and in 1794 described a technique for titrating acetic acid with potassium tartrate. (The appearance of sediment consisting of undissolved potassium bitartrate marked the end of the process.) In his research on the intermediate and acid salts of carbonic and sulfuric acids, he obtained crystalline bicarbonates and bisulfates to demonstrate that the excess of acids in acid salts represented a chemical, rather than a mechanical, mixture.

Lovits was also the first to isolate a number of organic substances in the pure state. Through the use of a technique combining the principles of crystallization, distillation, and adsorption, he was able to prepare frozen acetic acid, anhydride alcohol, pure sulfuric ether, and many organic acids. He was the first to isolate glucose from honey, and he obtained two new acids—dichloracetic and trichloracetic—by subjecting acetic acid to the action of chlorine.

Lovits was active scientifically for only twenty years. He was often seriously ill, occasionally as a result of his experiments, and survived a number of accidents. One of the most dedicated of chemists, he found satisfaction and joy only in his research.

BIBLIOGRAPHY

I. Original Works. A collection is T. E.Lovits. Izbrannye trudy po khimii i khinlicheskoy tekhnologii (“T. E. Lovits. Selected Works in Chemistry and Chemical Technology”; Moscow, 1955), ed. and with notes by N. Figurovsky. A partial list of individual works is given by Poggendorff.

II. Secondary Literature. A biography is Figurovsky, op, cit., 405-514; see also his Leben und Werk des Cheinikers Tobias Lowitz (Berlin, 1959); A. N. Scherer, Worte der Erinnerung an das Leben and die Verdienste von Tobias Lowitz (St. Petersburg, 1820); and P. Walden, “Tobias Lowitz, ein vergessener Physikochemiker,” in Diergart, ed., Beitrage zur Geschichte der Chemie (Leipzig, 1909), 533-544.

N. Figurovsky