De la Boe Sylvius (1614-1672), though not by his pupil Otto Tachenius, and by J.
De la BoÃ« Sylvius (1614-1672), who regarded medicine as applied chemistry, and Otto Tachenius, who elucidated the nature of salts.
The importance of ascertaining the proximate composition of bodies was clearly realized by Otto Tachenius; but the first systematic investigator was Robert Boyle, to whom we owe the introduction of the term analysis.
Quantitative chemistry had been all but neglected before the time of Lavoisier, for although a few chemists such as Tachenius, Bergman and others had realized the advantages which would accrue from a knowledge of the composition of N N N bodies by weight, and had laid down the lines upon which such determinations should proceed, the experimental difficulties in making accurate observations were enormous, and little progress could be made until the procedure was more accurately determined.
Potassium sulphate, K2S04, a salt known early in the 14th century, and studied by Glauber, Boyle and Tachenius, was styled in the 17th century arcanum or sal duplicatum, being regarded as a combination of an acid salt with an alkaline salt.