666 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



the subject of the gun and projectiles again before the Polytech- 

 nic, on Thursday evening next, or as early as convenient, and — 

 inasmuch as you cannot keep your next week's column open late 

 enough to receive the report of the sitting — to publish the letter 

 and explanatory notes in your next issue, to be followed by a 

 report of any discussions which may then arise. 

 Very truly yours, 



WASHINGTON A. BARTLETT. 



The following is General James' letter : 



Providence, R. I., April Uth, 1861. 

 To Washington A. Bartlett, Esq. : 



My Dear Sir : My attention has been directed to the discussion 

 at the " Polytechnic Association of the American Institute," of 

 " steel plated ships," during which you were unintentionally led 

 into an error in statements regarding the penetration of my pro- 

 jectiles, while members of the Institute made other statements 

 so widely different from the facts, that I deem it due to the able 

 manner in which you advocated the merits of my invention, to 

 furnish you with facts, and such extracts from the official report 

 of the Board, as will enable you to sustain the position already 

 taken. 



" In reference to the target which Mr. Babcock (I quote from 

 the Scientific American) says he saw, and also the penetration 

 and the number of shots which passed through,'^ the following 

 extracts from the report of the board of officers (one of whom, 

 Lieutenant Balch, U. S. A., constructed the target, and who made 

 the experiments), must be conclusive. 



The report says: "For ascertaining the penetration of the 

 shot, a target 16 feet 4 inches wide, 13 feet high, and 39 inches 

 thick, made of well-seasoned, very hard white oak timber, was 

 placed directly in front of the middle of the 2000 yards (distant) 

 target, having its face fifteen feet in advance of it. This butt 

 was composed of three thicknesses of timber, each stick 13 inches 

 deep and 11^ inches wide; — the front and rear tiers being up- 

 right, and the middle one horizontal. 



As each stick had been dressed perfectly true, in a planing 

 machine, they fitted closely, and formed a compact mass which 

 was firmly held together by means of four horizontal straps of 

 oak, two in front and two in rear, through which passed twenty 



