TO CORRESPONDENTS. 



Mr. KEITH'S Paper, which we regret to have been again obliged to 

 defer, will certainly appear in our next Number. 



The First Part of " The Herschelian" has been received for review. 



YOUNG'S CALCULUS. 



Just published, Price Seven Shillings in Cloth, 



T7LEMENTS OF THE DIFFERENTIAL CALCULUS, with its 

 Lj Applications to the GENERAL THEORY of CURVE SURFACES, and 

 of CURVES of DOUBLE CURVATURE, wherein are pointed out and cor- 

 rected some important Errors that have hitherto remained unnoticed in the Writings 

 of LAGRANGE, LACROIX, and other Analysts. 



By J. R. YOUNG, 

 Author of " Elements of Analytical Geometry," &c. 



Printed for J. Souter, School Library, 73 St. Paul's Churchyard. 

 Of whom may be had, 



1. AN ELEMENTARY TREATISE ON ALGEBRA, Theoretical and 

 Practical ; with attempts to simplify some of the more difficult parts of the Science, 

 particularly the Demonstration of the Binomial Theorem, in its most general form ; 

 the Solution of Equations of the higher orders; the Summation of Infinite Series, &c. 

 By J. R. YOUNG. 8vo. bds. 10s. 6d. 



" A new and ingenious general method of solving Equations has been recently dis- 

 covered by Messrs. H. Atkinson, Holdred, and Horner, independently of each other. 

 For the best practical view of this new method and its applications, consult the Ele- 

 mentary Treatise on Algebra, by Mr. J. R YOUNG, a work which deserves our cordial 

 recommendation." Dr. Gregory's Edition of Hutton's Mathematics, vol. i. p. 261. 



" For the summation of infinite series the author gives a new and ingenious method, 

 which is very easy and extensive in its application." Newcastle Magazine, Nov. 1825. 



2. An Elementary TREATISE on the COMPUTATIONS of LOGARITHMS, 

 Intended as a Supplement to the various Books on Algebra. By J. R. YOUNG. 12mo. 

 2s. 6d. 



3. ELEMENTS OF GEOMETRY; containing a new and universal Treatise on 

 the Doctrine of Proportions, together with Notes, in which are pointed out and cor- 

 rected several important Errors that have hitherto remained unnoticed in the writings 

 of Geometers. By J. R. YOUNG. 8vo. 8s. 



*' His observations on the theory of parallel lines, the labour he has bestowed on the 

 doctrine of proportion, as well as his corrections of many errors of preceding Geometers, 

 and supplying their defects, together with his minute attention to accuracy through- 

 out, may be justly considered as rendering his performance valuable, especially to the 

 learner." Philosojihical Magazine, March 1828. 



" In the notes which he has appended to the volume is much valuable matter, even 

 for those who have advanced still further in these studies. On the theory of parallel 

 lines, which has not a little perplexed geometers of all ages, there is a very able and 

 elaborate commentary." The Times, November 2, 1827. 



" We have never seen a work so free from pretensions and of such great merit." 

 Monthly Magazine, September 1827. 



4. THE ELEMENTS OF ANALYTICAL GEOMETRY; comprehending 

 the doctrine of the Conic Sections, and the general theory of Curves and Surfaces of 

 the second order, with a variety of local Problems on Lines and Surfaces. Intended 

 for the use of Mathematical Students in Schools and Universities. By J. R. YOUNG. 

 75. cloth. 



" If works like the present be introduced generally into our schools and colleges, the 

 Continent will not long boast of its immense superiority over the country of Newton, in 

 every branch of modern analytical science." The Atlas, July 25, 1830. 



%* For other recommendations of Mr. Young's Works see the Newcastle Magazine 

 for August; Monthly Magazine for September; and Ladies' Diary for J831, p. 25. 



A BRIEF TREATISE on the USE and CONSTRUCTION of A CASE of 

 MATHEMATICAL INSTRUMENTS; containing a copious Explanation of 

 each ; particularly the Sector, the lines of which are separately treated of, and their use 

 shown in solving several cases of Trigonometry. The whole designed to give the Stu- 

 dent a knowledge in using his Instruments, and constructing Geometrical Figures 

 with accuracy. By GEORGE PHILLIPS, B. A. Queen's College Cambridge, New 

 Edition, 2*. 6d. 



