308 Mr. Mallet on the Physical Conditions 



a short time, presented by their projectors for proof at Woolwich, 

 have arisen in every case from gross ignorance, on the part of their 

 designers, of the first and most obvious dynamic and other princi- 

 ples, upon which the arrangement and proportioning of such must 

 depend. 



2°. That the injurious effects of internal local heating, and unequal expan- 

 sion, must be far more destructive of such guns than of those 

 formed in a single mass. This is exactly the contrary of the con- 

 clusion that a just consideration of the properties induced by the 

 construction, in internal compressed and external extended plies, 

 warrants, as will be obvious to the mathematical reader of Note 

 CC and Chaps. 8-14. 



3°. That increased, and a highly injurious form of, corrosion may be 

 expected to occur in such guns, penetrating the joints between 

 the adjacent rings, &c., and so forcing them asunder. The simple 

 answer is, — abundant means are at hand, to so far prevent all 

 corrosion, that the objection has no weight ; nor has this taken 

 place in the old bombards, to which no care has been given 

 (Note A). 



37. — Resume and Conclusion. 



317. We have thus pursued the subject to its end — which never contem- 

 plated any but incidental treatment, of the practical mechanical operations, 

 necessary to the perfection of ordnance, important as these are, and well 

 deserving of a separate work, of greater compass than has yet appeared ; 

 but rather the bringing such light, as the exact and systematic application 

 of physical and mechanical science could throw upon the chief principles, on 

 which the true design in form and fabric, and the choice and modes of appli- 

 cation of materials for artillery, must rest. 



The author, so far as his reading has enabled him to judge, believes this 

 has been now attempted for the first time in a collected form. 



318. Many and elaborate experimental researches will yet be requisite 

 before all the data, upon which the art of the gun-founder must rest, shall be 



