422 MEMOIR OF DANIEL TREADWELL. 



Although the gun-carriage and recoil apparatus were not adopted by our Ordnance 

 Bureau, subsequently, as appears by the following letter, its value was appreciated by 

 some of the more intelligent officers. 



To Professor Daniel Treadwell, Cambridge, Mass. 



Naval Observatory, Washington, January 27, 18G9. 

 Dear Sir, — I am getting together some notes on the subject of gini-carriages, and, if I do 

 not mistake, I saw on board the U. S. Revenue Steamer McLane, in the Gulf, during the Mexican 

 War, a mode of compression involving the same principles made use of by Ericsson in liis latest 

 plan of the Dunderberg. The McLane's carriages, I understood, were of your invention. 



If so, will you be so good as to furnish me with a sketch of the arrangement ; the notes will 

 be published for the use of the Naval Academy, and I desire to give credit to the several inven- 

 tors, among whom you are one of the earliest and most distinguished. 



Very respectfully, 



William N. Jeffers, Commander U. S. Navy. 



To William N. Jeffers, Esq., Commander in the U. S. Navy, Naval Observatory, Washington. 



Cambridge, January 30, 1869. 

 Dear Sir, — In answer to your letter of the 27th instant, I have to say that I have no 

 knowledge of the gun-carriages used on the U. S. Revenue Steamer McLane. But I herewith 

 enclose to you a pamphlet published by me in the year 1845, entitled "A Slioi-t Account of an 

 Improved Cannon." On pp. 14, 15, and 16 of this pamphlet will be found a general description of 

 a method, and apparatus, for restraining the recoil of ordnance, invented by me in 1842. Two 

 of my wrought-iron 32-pounders were mounted upon carriages, constructed by me, with this 

 apparatus, and arc now probably in the Ordnance Department of the Navy Yard in Charlestown. 

 It was fully proved, by a long course of experiments, that this method of controlling the recoil is 

 entirely efficient. 



So far as I know, the method of increasing the resistance of the friction of a given load, or 

 pressure, by an increase of the number of the plates, or surfaces, upon which the load acts, was 

 first applied to a useful purpose in this apparatus. Nor am I aware that the fact that the 

 resistance of friction could be so increased, or that the law of the increase of the resistance 

 follows the direct arithmetical increase of the number of the plates or surfaces upon which the 

 load or pressure acts, had been pointed out by any experimenter or writer before it was recog- 

 nized by me. 



No patent has been taken in this country for tliis method of governing the recoil of guns, but 

 a patent was taken for it, on my account, in England, in the year 1845. Tiiis English patent 

 was taken by and in the name of Thomas Aspinwall, then U. S. Consul in London. I have no 

 copy of the English patent, but it can undoubtedly be found at full length in the " Specifications 

 of Patent Inventions " published by the English government. A copy of this great publication 

 is or ought to be found in the Congressional Library. 



Very respectfully, your servant, 



Daniel Treadwell. 



