The widespread interest in the burning of sulfur and of phosphorus, naturally, caught Lavoisier's attention. In his first volume of _Opuscules Physiques et Chimiques_ (1774), he devoted 20 pages to his experiments on phosphorus. He amplified them a few years later[10] when he attributed the combustion to a combination of phosphorus with the "eminently respirable" part of air. In the _Methode de Nomenclature Chimique_ of 1787, the column of "undecomposed substances" lists sulfur as the "radical sulfurique," and phosphorus, correspondingly, as the "radical phosphorique." The acids are now shown to be compounds of the "undecomposed" radicals, the complete reversion of the previous concept of this relationship. A part of the old analogy remained as far as the acids are concerned: sulfuric acid corresponds to phosphoric; sulfurous acid to phosphorous acid with less oxygen than in the former.[11] Early Uses In the 18th century, phosphorus was a costly material. It was produced mostly for display and to satisfy curiosity. Guillaume Francois Rouelle (1703-1770) demonstrated the process in his lectures, and, as Macquer reports, he "very often" succeeded in making it.[12] Robert Boyle had the idea of using phosphorus as a light for underwater divers.[13] A century later, "instant lights" were sold, with molten phosphorus as the "igniter," but they proved cumbersome and unreliable.[14] Because white phosphorus is highly poisonous, an active development of the use in matches occurred only after the conversion of the white modification into the red had been studied by Emile Kopp (1844), by Wilhelm Hittorf (1824-1914) and, in its practical application, by Anton Schroetter (1802-1875).[15] [Illustration: Figure 3.--DISTILLATION APPARATUS (1849) for refining crude phosphorus. The crude phosphorus is mixed with sand under hot water, cooled, drained, and filled into the retort. The outlet of the retort, at least 6 cm. in diameter, is partially immersed in the water contained in the bucket. A small dish, made from lead, with an iron handle, receives the distilled phosphorus. (From HUGO FLECK, _Die Fabrikation chemischer Produkte ..._ page 90.)] The most exciting early use, however, was in medicine. It is not surprising that such a use was sought at that time. Any new material immediately became the hope of ailing mankind--and of striving inventors.[16] Phosphorus was prescribed, in liniments with fatty oils or as solution in alcohol and ether, for external and internal application. A certain Dr. Kramer found it efficient against epilepsy and melancholia (1730). A Professor Hartmann recommended it against cramps.[17] However, in the growing production of phosphorus for matches, the workers experienced the poisonous effects. In the plant of Black and Bell at Stratford, this was prevented by inhaling turpentine. Experiments on dogs were carried out to show that poisoning by phosphorus could be remedied through oil of turpentine.[18]