of Kaiiind Fhiloso^hy. 129 



substances which existed only in their own iiaaginalions. 

 If it be desirable, in stud)ang Natural Philosophy, to ac- 

 quire just ideas of the properties and mutual actions of 

 bodies as they actually are, those experimental details by 

 which the results of theory are modified and corrected, 

 must enter extensively even into an elementary treatise. 

 But in this respect, the original work of Enfield is almost 

 totally deficient. Like those from which it is borrowed, it 

 contains little more than a naked series of mathematical 

 principles;"^' with scarcely an intimation that any of them 

 are at variance with facts. Nor do we think that the edi- 

 tors of later editions have been fortunate in their at- 

 tempts to supply the deficiency. We look in vain to the ad- 

 ditions they have made, for any account of the late research- 

 es of philosophers into the nature and laws of action of 

 those modifying causes which were once regarded as too 

 stubborn to yield to calculation, and which theory according- 

 ly overlooked. The names of Bossut, Coulomb, Button, 

 Dalton, Biot, Young, and other great experimentalists who 

 have almost created a new era in philosophy, by their suc- 

 cess in gleaning up the scattered laws of nature which New- 

 ton and his cotemporaries left behind them ; in compelling 

 empirical formulse to perform the office of laws where the 

 subject is incapable of theoretical investigation ; and in as- 

 certainingthe precise valuesof those arbitrary constant quan- 

 tities without which laws themselves are incapable of prac- 



* While we rrfrard (liis work as too exclusively mathemiitical in its con- 

 tents, we would by no means wisii to see its present matliemafical foria 

 discarded. With the exception of electricity, magnetism, and a few topics 

 included under other branches, to which tliis mode of discussion is certainly 

 til suited, we regard tlie form of proposiiion and demonstralion into which 

 Enfield has thrown his Insliliites as constituting; its chief recommendation, 

 when compared with most other elementary works. It disciplines tlie stu- 

 dent more effectually, and renders his task better defined, tlian a more loo.se 

 and f)opularform ; and at the same time facilitates the employment of the 

 jnstructer and examiner. We will add, that so far as our own espeiienct; 

 extends, tiie mode of discussing physico-mathematical suhjects wiiich was 

 fashionable a century agn, that is, by a statement of princi()!es in common 

 language, and demonstrations annexed, is far superioi', for Hie purposes of 

 elcnienlary ri!struclion,to the modern analytical mode, in which the theorem 

 terminates the investigation, and is expressed by an algebraic formula. 

 The employment of the latter mode is doufUless occasionaHy necessary, 

 and it is almost always the most concise ; but the former, whenever it can 

 be employed, lias allogelhcr the advantage in its power to interest, and to 

 impress fheimagina'.ion and memory of the stndeiit, while it i" incompara- 

 bly better fitted to the ;)urposes of recitation. 



Vol. in. ....No. 1. 17 



