>6 



OX THE CONSTRUCTION OF HOOPED CANNON 



permit^ two guns constructed upon the principles and after the proportions 



Memoir of 1855, both of these guns being supposed to be of the 



iron throughout, but differing only 

 in this, viz., that, in the one, the hoops are put upon the body in an annealed 

 state ; and, in the other, in such a state of hardness, produced by cold hammering 



given in the 



tame size, ant 



made of the same quality of 



and stretching (as hereafter described), as shall bring the 



iron, as near as may be 



to the state of the wire represented in Fig 



3 



The 



gun 



be 



■ 



tly described as having a caliber of 14 inches diam- 



ce, so as to make the 



eter; bodies of cast-iron, 7 inches thick in the reinfo 



hoop 

 of tl 



diameter of the body there 28 inches; and a covering 



ayers, havin 



qua! thickness of 7 inches. 



of wroug 

 The st 



gtl 



cast-iron bodies, as shown in detail in the former Memoir, if made of 



of 30,000 pounds tensile 



o 



th 



duced 



mg 



to Mr. B 



low's formula (which is recognized as sufficiently perfect for a practical guide) 



of 

 of 



be 210,000 pounds for each inch in length. 



ow, let us suppose one of these bodies to be hooped with two 

 hoops, 3] inches each in thickness, these hoops being made of wid 



N 



ayers 

 bars 



d like 



ribbon 



d 



being welded so as to form 



upo 



a block, and in this state the 



hoops, being thus formed and 



ring, or hollow cylinder, or hoop* 



The 



to be left 



annealed 



properly forged to shape and size 



are su 



or even .003 of th 



they are to enclose, we will suppose them 

 where they cool and 



pposed 



and, after being bored and finished to .001, .002, 

 diameter less than 



the 



P 



of the body that 



comp 



the 



to be heated and put in the 



place 



? 



strained and stretched by the resistance 



being themselves at th 



same time 



ever proportions this compression and this 



of the enclosed body. Now, what 



it must be evident, ft 

 upon the hoops, ft 

 to 120 pounds 



gat 



stretch may bear to each other, 



Let 



upo 



an inspection of Figure 4 

 nking, reaches 17,675 pound 



that. 

 P 



hen the strain 



incl 



q 



ual 



us 



suppose 



&' lvnu,w -u,o/o pounds per square men (eqiau 

 the wire), they will rece i V e a decided permanent elon- 



force of 17,675 pounds 

 Powder has distended the 



that the hoop 



are 



per square inch, 

 cast-iron to its 



graspin: 

 at the instant 

 normal diamete 



the body 



th 



w 



he 



n 



the 



fired gun- 



We see 



by the 



* A more full account of „£ 

 b y me in 1845, or in -RnrfiA P - f , g ""S 8 ma ? be f <>und in the pamphlet published 



° ' d deifications" No. 10,013; enrolled in July, 1844; printed 



in 1851. 



