TRANSLATOR S INTRODUCTION. xix 



printing of his eternal twenty-six pages, 104 

 florins 50 kreuzers. 



That this Appendix was finished consider 

 ably before the Vol. I, which it follows, is 

 seen from the references in the text, breath 

 ing a just admiration for the Appendix and 

 the genius of its author. 



Thus the father says, p. 452: Elegans est 

 conceptus similium, quern J. B. Appendicis 

 Auctor dedit. Again, p. 489: Appendicis 

 Auctor , rem acumine singulari aggressus, Ge- 

 ometriam pro omni casu absolute veram posuit; 

 quamvis e magna mole, tantum summe neces- 

 saria, in Appendice hujus tomi exhibuerit, 

 mtiltivS (ut tetraedri resolutione generali, plu- 

 ribusque aliis disquisitionibus elegantibus) 

 brevitatis studio omissis. 



And the volume ends as follows, p. 502: Nee 

 operae pretium est plura referre; quum res 

 tota exaltiori contemplationis puncto, in ima 

 penetranti oculo, tractetur in Appendice se- 

 quente, a quovis fideli veritatis purae alumno 

 diagna legi. 



The father gives a brief resume of the re 

 sults of his own determined, life-long, desper 

 ate efforts to do that at which Saccheri, J. H. 

 Lambert, Gauss also had failed, to establish 

 Euclid s theory of parallels a priori. 



