of the late P. Nieuwland. 73 



we fhonld continually have the fame feafon, and the days 

 and the nights always equal. The caufe, however, of this 

 inclination was (till unknown to all the great aftronomers. 

 Du cjour fays, in his analytical treatife on the apparent 

 motion of the heavenly bodies, that it is highly probable that 

 this phenomenon depend? on fome phyfical caufe ; but he 

 does not venture to mention it. Nieuwland proo cded far- 

 ther. He laid down principles from which he drew this 

 conclufion, that the above phenomenon is intimately con- 

 nected with the whole fyftem of attraction. On thefe prin- 

 ciples he made calculations, the refult of which was exactly 

 equal to the angle of the inclination of the earth's axis to 

 the plane of its orbit. Nieuwland communicated his difco- 

 very with much modefty to the celebrated Profefibr Damert 

 at Leyden, who propofed fome objections to it which dis- 

 couraged Nieuwland, and induced him to revife his calcula- 

 tions with more accuracy. Major von Zach tranfmitted the 

 paper which contained them to M. De la Place at Paris, and 

 caufed it to be printed alfo, for the opinion of the learned, 

 in the Supplement to Profeffor Bode's Aftronomical Alma- 

 nack for the year 1793. 



Nieuwland's talents and diligence foon recommended him 

 to the notice of his country. When in his twenty-fecond 

 year, he was appointed a member of the commiffion chofen 

 by the College of Admiralty at Amfterdam for determining 

 the longitude and improving marine charts. On this labour 

 he was employed eight years, and undertook alfo to prepare 

 a nautical almanack, and to calculate the necefiary tables. 

 The mathematical part was in general entrufted to Nieuw- 

 land ; but he affifted alfo his two colleagues van Swinden and 

 van Keulen, in the departments affigned to them, with fuch 

 affiduity, that mod of the work publifhed on the longitude, 

 together with the three additional parts, were the fruits of 

 his labour. In the fecond edition of the explanation of the 

 nautical almanack, he had alfo the principal fhare, and he 

 was the author, in particular, of the explanation of the equa- 

 tion 



