VOL. XI.] PHILOSOPHICAL TRANSACTIONS. SOf 



2d. Bi/ Mr. Colson, at JVappingy near London. 



h. m. ■. 



4- Digit was observed eclipsed at... 7 51 31 



3-rV 8 23 21 



4 9 49 O 



The eclipse was not ended at 9 55 36 » 



It was observed as ended at g 57 6 



The times corrected by observed altitudes. 



An Account of some Books. N° 126, p. 638. 



I. Elemens des Mathematiques, ou Principes Generaux de toutes les Sci- 

 ences qui ont les Grandeurs pour Object: par J. P. A Paris, 1675, in quarto. 



The author of this work, Jean Prestet,* delivers a short and easy method to 

 compare quantities, and to discover their proportions and relations to each other, 

 by characters of numbers and letters of the alphabet ; affirming to have here 

 demonstrated things in a geometrical order, and rendered the algebraical ana- 

 lysis much easier, and treated the same more fundamentally than has been done 

 hitherto. 



By quantity he understands here not only the extension in length, breadth, 

 and depth, but whatsoever we conceive to be capable of more or less, and that 

 can be exactly measured, whether it be exactly known, or supposed such. He 

 considers, that though arithmetic be a science on which all others depend, yet 

 it is this algebra which serves to elucidate, extend, and perfect, as much as is 

 possible, arithmetic, and generally all the sciences that relate to the mathematics : 

 it being so general that it considers all quantities, and what it demonstrates 

 being capable to be applied, not only to numbers, lines, and figures, weights 

 and velocities, but also, to all such numbers, lines, velocities, and particular 

 quantities, as you can conceive in each species of quantities. 



But it is not only the extent and universality of algebra for which he com- 

 mends it, but also the facility it affords to the mind of discovering the most 

 hidden truths. 



♦ John Prestet, a priest of the oratory, was bom at Chalons-sur-Saone, in l658. He went to Paria 

 early in life, where having finished his studies, he was entertained by father Malbranche, who, 

 finding he had a genius for the sciences, taught him matliematics, in which his young pupil made so 

 rapid a progress, that at 17 years of age he published the first edition of his Elemens de JVIathema- 

 tiques. In the same year, \675, he entered the congregation of the oratory, and taught mathematics 

 with distinguished reputation, particularly at Angers and at Nantes. He died June 8, 1690, at Ma- 

 lines. His Elemens, above noticed, contain many curious problems. The best edition is that of 

 l689> in 2 volumes 4to. 



RR 2 



