SKETCH OF KARL WILHELM SCHEELE. 843 



on black magnesia, or the binoxide of manganese, which M. Cleve 

 suggests may have been the most important that he made, he discov- 

 ered that the basis of the mineral was a new fundamental body, man- 

 ganese ; that it contained, as an impurity, a new earth, baryta, and 

 that when it was treated with muriatic acid another new substance 

 was evolved, chlorine. Further experiments with the last substance 

 revealed its bleaching qualities, which have been so extensively applied 

 in the arts. Finding that the presence of white arsenic helped the 

 solution of the oxide of manganese in acids, he experimented with that 

 body, and discovered the more important arsenical compounds. Scheele 

 discovered that phosphorus was the cause of cold-shortness in iron, and 

 showed that argillaceous earth was distinct from silicious earth, and 

 not an acid-worked modification of it, as had been supposed. He ex- 

 perimented with plumbago, and found that it was " a kind of mineral 

 sulphur or carbon, composed of carbonic acid and a large quantity of 

 phlogiston," or, as we would express it, of carbon, and showed that it 

 was the insoluble substance that occurred in cast-iron, thus opening 

 the way to the further researches that have been made in the differ- 

 ences between iron, cast-iron, and steel, which, still under prosecution, 

 lie at the foundation of our greatest industries. Connected with this 

 investigation, on account of the resemblance of the minerals to graph- 

 ite, were his researches in molybdenum and in wolfram. The last 

 resulted in the discovery of the metal tungsten, for which the name 

 Scheelium has been proposed. 



Very little was known of organic compounds in Scheele's time. It 

 is one of his great titles to merit that he first opened the way to the 

 rich field of the fruitful and enriching discoveries that distinguish the 

 medical and industrial chemistry of our day. The first in order of his 

 researches in this line is his memoir on Prussian-blue, which well illus- 

 trates the readiness with which, bringing his extraordinary penetration 

 to bear, he was able to arrive at the truth. In the course of his 

 research he obtained a colorless liquid, which he described as " a 

 substance having a curious odor, but not disagreeable, with a taste 

 somewhat like that of sugar, which heated the mouth slightly and 

 provoked coughing." He little imagined that he had in his hands 

 one of the deadliest poisons known, prussic acid ; and we shudder 

 when we think how near it might have come to making an end of 

 him. His researches on the different species of alcohol, described in 

 1782, indicate that he obtained aldehyde, a substance which has since 

 been the starting-point for numerous important combinations, but of 

 which the discovery is attributed to Liebig, in 1835 ; he appears also 

 to have encountered chloral in his researches. 



The preparations made in his shop led Scheele, in 1783, to the dis- 

 covery of glycerine, which was at first called Scheele's sweet prin- 

 ciple of oils. Boiling oxide of lead with water and oils, he obtained 

 a plaster which he called a kind of hard soap, and which was not 



