Notices respecting New Books. 537 



learning and ability displayed by him in the adoption of methods for 

 the construction of his tables. After exhibiting various modifications 



of the function a* , first applied by Mr. Gompertz to these investi- 

 gations, Mr. Farren makes use of the calculus of finite differences 

 for the purposes of interpolation till the age of seventy-one. After 

 that age, because "the admissions are too fev^- to admit of the suj)- 

 position that the same mixed generic law will continue to prevail," 



f »•'■— 1 

 he has recourse to the formula X' l=X'l r, by means of which, 



and the theory of equations of ?i dimensions, the remainder of the 

 table is interpolated. 



Lastly, the means are afforded of tracing, from the original data, 

 the several values made use of ; so that the whole series of opera- 

 tions may be followed, and the connexion between the first and last 

 values easily confirmed. As Mr. Farren wisely observes, " all mo- 

 dern publications on these subjects must principally depend, for 

 even ordinary acceptance, upon the attention paid to such details ; " 

 nothing, he maj^ be assured, was better calculated to secure for his 

 labours the confidence they so evidently deserve. He is quite right, 

 we think, when he says that tables of mortality solely depending for 

 their adoption on the authority of the authors framing them, will 

 eventually be discarded. 



Brief Astronomical Tables for the Expeditious Calculation of Eclipses 



in all ages. By W. Drew Snooke. S. Highley and Son, Fleet 



Street. 



These tables are constructed with the view to enable the histo- 

 rical student to verify dates by the calculation of eclipses named 

 in history. For this purpose strict mathematical accuracy may 

 be dispensed with ; and the smaller equations which enter into 

 the determination of the times of full and new moon, and the rela- 

 tive position of the three bodies, may with more or less risk of error 

 be omitted from the calculation. The tables are well arranged, and 

 the rules for using them clearly expressed and exemplified. 



I'he author appears to handle his subject with familiarity ; and if 

 tlie correctness of the tables may be relied ujion, and the time and 

 other circumstances of the pha?nomena to which they are applicable 

 is capable of being educed from them with that degree of accuracy 

 which the author affirms, we tliink his little book may be found 

 useful in sujjplying a desideratum which is likely to have been felt 

 by many of the class of students for whose use it is intended. 



Preparing for Publication. 



An Elementary Introduction to the Study of Palseontology ; with 

 numerous Figures Illustrative of Structural Details, By F. M'Coy, 

 Professor of Geology and Mineralogy, Queen's College, Belfast. 



Also, by the same Author, 

 A Manual of the Genera of British Fossils ; comprising Systematic 



