Notices respecting New Booh. 69 



having however continued the distillation for about a week I 

 could not obtain an acid from benzol. On employing highly 

 diluted acidj the benzol uas gradually converted into nitro- 

 benzol. 



Neither benzol nor nitrobenzol is attacked by pure chro- 

 mic acid, or the oxidizing mixture of bichromate of potash and 

 sulphuric acid. Results quite as unsatisfactoiy as these were 

 obtained on boiling a solution of hyposulphobcnzolic acid 

 with chromic acid or peroxide of manganese. 



XI. Notices respecting New Books. 



RECENT CAMBRIDGE WORKS ON PURE MATHEMATICS. 



1. Euclid's Elements of Geometry, SiC. By Robert Potts, M.A. 

 Trinity College, 8vo. Parker, 1845. 



2. School Edition of Potts' s Euclid, &;c, 12mo. Parker, 1846. 



3. Appendix to the larger edition of Potts' s Euclid. Parker, 1847. 



4. Solutions of the Trigonometrical Problems proposed at St. John's 

 College from 1829 to 1836. By Thomas Gaskix, M.A., late 

 Felloiu and Tutor of Jesus College. Deightons, 1847. 



5. Solutio>is of Geometrical Problems, consisting chiefly of examples 

 in plane coordinate Geometry, proposed from Dec. 1 830 to Dec. 

 1836, by the same. Deightons, 1847. 



THESE two sets of works, though as opposite in their manner as 

 if they had been written for the sake of contrast, are yet so far 

 related in respect to their subject as to be properly analysed under 

 the same heading. The object of Mr. Potts is to develop the pure 

 principles of the ancient geometry ; that of Mr. Gaskin to display the 

 powers of the modern to the greatest advantage. Each too has been 

 eminently successful in his undertaking ; and has shown the most 

 admirable mastery over his respective subject. We are indeed glad 

 to see this ; as for many years the elementary productions of the 

 Cambridge press had been gradually diminishing in value, originality, 

 and adaptation to educational purposes. We shall give a brief 

 account of them in the order of their appearance, beginning with 

 Mr. Potts's Euclid and Appendix. 



The Elements of Euclid, it may be supposed, cannot differ mate- 

 rially in one edition from another ; especially when, as is the case with 

 most of them as well as this, the text of Simson is professedly adopted. 

 This is true in tlie main : but it is not true in respect to the busi- 

 ness of actual instruction, as every tutor too well knows. In using 

 the older editions of Simson nothing is so embarrassing to a stu- 

 dent or so troublesome to the tutor, as the parcelling out the syllo- 

 gisms (or ratlier, generally, the enthymcmes) of which a long de- 

 monstration is comjjosed. Many tutors had recourse to marking them 

 in pencil in the pupils' copies of the book. 'I'hen again came the 

 separation of each syllogism into its separate members. All this 

 created not only intolerable labour for the tutor, but disgust in the 



