74 Biographical Memoirs 



tion of time, the method of determining the going of a time- 

 piece, and of calculating the declination of the moon. 



Soon after Nieuwland engaged in this employment it ap- 

 peared as if his deflination was about to be changed. In 

 the year 1787 he was chofen by the States of Utrecht to fuc- 

 ceed Profeflor Hennert ; but on account of certain circum- 

 ftances this appointment did not take place. He was how- 

 ever invited to Amfterdam by the magistrates of that city, 

 to give lectures on the mathematics, aftronomy, and naviga- 

 tion. While in this fituation he wrote his ufeful and excel- 

 lent treatife on navigation, the firft part of which was pub- 

 lifhed at Amfterdam in 1793, by George Hulft van Keulen ; 

 and it is much to be wifhed that M. van Swinden would 

 complete this work from the papers bequeathed to him by 

 his deceafed friend the author. 



In aftronomical purfuits, Nieuwland applied not only to 

 the theoretical but alfo to the practical part •, and in this- 

 ftudy he was encouraged and afllfted by Major von Zach, 

 with whom he refided fome time in the courfe of the year 

 1792, after the death of his wife, and who inftru£ted him in 

 the proper ufe of the fextant. This affectionate friend pub- 

 Kfhed alfo all his obfervations and calculations in the before - 

 mentioned Supplement to Bodc's Aftronomical Almanack. 



In the year 1789 Nieuwland was chofen member of a 

 learned fociety whofe object was chemical experiments ; and 

 fo apt was his genius for acquiring knowledge, that in a 

 little time he made himfelf completely matter of the theory 

 of chemiftry. A proof of this is the treatife which he read 

 on the 24th of May 179 1, in the fociety diftinguifhed by the 

 motto of Felix Meritis, and which has been printed in the 

 firft part of the New General Magazine (Niew Algemeeh 

 Magazyn). At the fame time he was able to examine the 

 important difcoveries made by the fociety, to affift in pre- 

 paring an account of them for the prefs, and to publifh them 

 with fufRcient accuracy in the French language. Three 

 parts of this work appeared under the title of Recherches 



\ Pkyfico- 



