Chemiluminescence 435 



the continent. Although Frederick Hoffman the younger (1660- 

 1742) , professor of medicine at the University of Halle and a Ger- 

 man, recognized the part played by Krafft and Kunckel in the early 

 history of phosphorus, he attributed the perfection of the method 

 of preparations to the illustrious Boyle. In his book, Observationum 

 Physico-Chymicorum Selectorum, libri III (Halle, 1736; 1st ed., 

 1722) , Hoffman described " Experimenta circa Phosphorum Angli- 

 canum " (Lib. Ill, Obs. XIV) , ten in number, paying particular 

 attention to its behavior when dissolved in essential oils. It is highly 

 significant that he should call the material " English phosphorus," 

 despite the many other names originally used on the Continent. 



Phosphorus ^^ was made in France by Jean Hellot (1685-1766), 

 and the method published in the Memoirs of the French Academy 

 for 1737, and in Macquer's Elemens de Chymie (1749), translated 

 by Andrew Reid in 1764. The French pharmacist G. F. Rouelle 

 (1703-1770) made phosphorus in public, during his lectures on 

 chemistry, and the Abbe Nollet (1748) experimented with it. 



In Germany in 1743, Marggraf (1709-1782) discovered a better 

 method of preparation from urine, published in his " Chymische 

 Schriften " (1761 and 1767) . He used urine with lead chloride 

 instead of sand, and also found phosphorus in wheat and mustard 

 seeds. In 1785 he reported additional methods. 



The preparation of phosphorus from bones is usually attributed 

 to J. C. Gahn working with C. W. Scheele in 1769. The discovery 

 was unnoticed until Lorenz von Crell (1744-1816) unearthed the 

 account in an Edinburgh medical society book, repeated the pro- 

 cedure with success, and published it in his Chemisches Journal for 

 for 1778. Stag antlers were said to be especially good sources of 

 phosphorus. 



Practically all the early chemists regarded phosphorus as a com- 

 pound. W. Homberg termed it an acid plus phlogiston. G. E. 

 Stahl and J. Hellot (1737) thought of it as hydrochloric acid plus 

 phlogiston, F. Hoffman as hydrochloric and sulphuric acid plus 

 phlogiston and H. Boerhaave as sulphuric acid plus phlogiston. 

 When burned the phlogiston escaped and the acid remained. 



A. S. Marggraf showed that the white phosphorus pentoxide, 

 formed as a result of burning, was heavier than the original phos- 

 phorus, and A. L. Lavoisier found that the acid weighed more than 

 the original phosphorus owing to something taken from the air, 



"A letter of J. G. Gmelin (1674-1728) of Tubingen to J. W. Dieterich of Niirnberg 

 indicated that Gmelin prepared phosphorus from urine and charcoal in Sweden in 

 1715. See H. Peters Phar. Ztg. 37: 607, 1892. 



