of Katural Philosophy. 1 33 



strength and stress of materials, with various others of minor 

 importance, are left entirely unnoticed. We are not prepar- 

 ed to decide how far these omissions are judicious. The 

 attention of the student may certainly be distracted by at- 

 tempting to crowd too great a variety of subjects within a 

 narrow compass; and it must be admitted that most of the 

 subjects just referred to, if introduced at all, must be treated 

 at some length, to render them useful, or even intelligible. 

 We should suppose, however, that some account of the 

 principles which determine the transverse strength of 

 beams, would not be misplaced, even in a work of this lim- 

 ited extent. 



In these remarks, which might, if necessary, be equally 

 extended to all the other branches, we would by no means 

 imply that the editors of Enfield are censurable for not 

 making all the changes in their author which would improve 

 him, — or that the attempt to make these changes, had any 

 one leisure and inclination for the task, would be an advisa- 

 ble one. It would be quite as easy, and on every account 

 much better, to write a new system. We have made them 

 to invite the attention ofthose who superintend the philo- 

 sophical department in our public seminaries, to the impor- 

 tance of putting it in their power to dispense with their 

 present text-book entirely, by furnishing one for themselves. 



As much the greater part of the erroneous statements of 

 former editions stand uncorrected in the last, we think it 

 will be doing the student an acceptable service, for the pres- 

 ent, to present him with a list of those which will be most likely 

 to mislead him, or to embarrass hisprogress. — The remainder 

 of this article being intended only for those who iwe sufti- 

 ciently interested in the subject to follow us with a copy of 

 Enfield in their hands, our comments will sometirfios be 

 made with more brevity than might otherwise be consistent 

 with clearness. 



Book I. Prop. 5. " Some bodies appear to pessess a pow- 

 er the reverse of the attraction of cohesion, called repul- 

 sion." Of the five experiments adduced in support of this 

 proposition, the first four, — namely, the depression of mer- 

 cury around iron, and in capillary tubes, the suspension of 

 a needle by water, and the depression of the surface around 

 a floating piece of tin-foil, — are so far from furnishing any 



