MEMOIR OF DANIEL TREADWELL. 479 



sive hoops of wrought iron, screwed on under suitable tension. The hoops to cover a part or the 

 whole length of the tube, and to consist of one or more layers over each other, as the size and 

 strength of the gun may require. 



This method of construction appears to promise a maximum strength with any given weight 

 of material in as high a degree as any other method now known or practised. The most success- 

 ful trials of projectiles recently made in England to penetrate iron targets were, according to 

 newspaper reports, made with cannon constructed on similar principles, which tends to confirm 

 Mr. Trcadwell's tlieory. At the present time it is an object of great importance to artillerists to 

 give the highest possible velocity to projectiles of great weight, in order to penetrate and destroy 

 heavy iron-clad defences ; and whatever means may be devised for giving greater strength and 

 safety to large cannon will promote that object. Among all the numerous methods which have 

 recently been suggested for improving large cannon, I have not seen any which appears better 

 adapted to that purpose than those proposed by Mr. Treadwell. I am tlierefore of opinion that 

 his invention is worthy of a trial. 



His processes of manufacture are, however, very expensive, and cannon made as he proposes 

 will cost much more than is now paid for any other large cannon of equal weiglit. His proposi- 

 tion to malvc one hundred guns of diiJ'erent sizes at the price named will, if accepted, require an 

 expenditure of about #340,000. I think it would be inexpedient to make a contract involving so 

 large an amount for any untried weapons, however confident may be the expectations of ultimate 

 success. Before making any contract for a large quantity of new weapons, an actual trial of 

 one or more of them should be made in connection with such otiiers now in use as are de- 

 signed for similar service ; the trials to be so arranged as could demonstrate conclusively the 

 relative merits or demerits of the new invention compared with models already in service. 

 Whatever practical value the new invention might be found to possess, either in capacity for 

 powerful work or for prolonged endurance, would thus be satisfactorily ascertained. 



If it shall be decided to make a trial of Mr. Trcadwell's cannon, I would suggest that one or 

 two of large size, say of eight or ten inch bore and rifled, be ordered upon the condition, that, if 

 on trial they proved to be satisfactory, they should be paid for at a stipulated price. And also, 

 that the Department may then at its option order an additional number for service at prices not 

 exceeding those stated in Mr. Trcadwell's proposition. 



Respectfully, I am your obedient servant, 



James W. Ripley, Brigadier-G-eneral. 



The propositions were not accepted, and no further efforts were made. 



In 1862, Captain Eodinan of the Ordnance made a detailed report of the re- 

 sults of experiments conducted at the expense of the Government in favor of a 

 gun of his own production. In this gun he restored the old method of casting 

 upon a core, and passed through the axis of the core a stream of cold water, in 

 order to produce a more perfect equilibrium among the particles of cast iron of 

 which it was composed than they have when the cooling is from the outside surface 

 only, as is the case with guns cast solid. 



Mr. Treadwell demonstrated that the strength of such guns is by no means in 

 proportion to the thickness of their walls; indeed, that the difficulty, if not the 

 impossibility, of securing the proper equilibrium among the several theoretical 



