288 EULOGY ON THE LATE GENERAL JOSEPH G. TOTTEN. 



II. " To determine whether these embrasures might have a form that would 

 shut out most of these missiles, and resist for a time the heaviest, without lessen- 

 ing the sector of fire, horizontal and vertical, of the casemate gun. 



III. " To determine the degree to which, without injury from the blast of the 

 gun, or lessening its scope of fire, the throat of the embrasure, and also the ex- 

 terior opening, might he lessened. 



IV. " To determine whether all smaller missiles might not be prevented from 

 passing through the throat into the battery ; and whether the smoke of the blast 

 might not also be excluded by simple and easily managed shatters." 



Targets were constructed representing the wall of a fortification pierced with 

 its embrasures. All varieties of materials were employed in the walls, and every 

 suggested method of consti ucting the embrasure was tried. General Totten's 

 report shows that the minutest detail of construction was directed by himself, 

 and that he personally superintended the experiments. They were carried on 

 at intervals during four successive years, the results of each year suggesting the 

 object of experiment for the next. 



It would be out of place here to follow the report through its detailed ac- 

 counts of the firings, or even to attempt to sum up the conclusions arrived at, 

 referring as they do to such a variety of subjects ; but those concerning the 

 thickness of the scarp-wall and the use of wrought iron may be properly quoted 

 as among the most important : 



" The general conclusion from these trials is, that, whether of cement concrete, of 

 bricks, or of hard stones, the portion of the wall at and around each embrasure 

 having the thickness of five feet only should be no larger than is indispensable 

 for the adaptation of the gun and carriage to the embrasure ; if restricted to a 

 small area, this thickness will suffice — not otherwise. 



" The thickness of five feet will resist a number of these balls, impinging in 

 succession on that space, provided the bond expand promptly above, below, aud 

 on each side, into a thickness greater by some two and a half feet or three feet 

 or more. Were the wall no thicker generally than five feet, being reinforced 

 only by piers some fifteen feet apart, it would soon be seriously damaged by 

 battering at short distances " 



And in reference to iron it is stated : " First, it may be fairly assumed that 

 a plate eight inches thick of wrought iron of good quality, kept in place by a 

 backing of three feet of strong masonry, will stop a solid ball from an eight 

 inch columbiad fired with ten and a quarter pounds of powder from the distance 

 of two hundred yards. The plate of iron wdl be deeply indented at the point 

 of impact, the ball carving for itself a smoot 1 bed of the shape and size of one 

 hemisphere, in which it will be found broken into many pieces easily separable, 

 and it will, besides, be somewhat bent generally. The masonry behind will 

 be much jarred, and, unless strongly bonded, be considerably displaced; more- 

 over, unless the thickness of three feet is well tied into thicker masses imme- 

 diately adjacent on the sides and above and below, the general damage will be 

 severe. 



" Second, this plate will be much the stronger for being in a single mass, and 

 not made up of several thinner plates. The continuity effected by bolts and 

 rivets of the made-up plates is broken even by weak assaults, so that after- 

 wards the stronger, instead of a joint opposition, finds only a succession of 

 feeble resistances. 



" Third, a thickness of two inches is ample for shutters designated to stop 

 the largest grape-shot. With this thickness they will be neither perforated nor 

 deformed by anything less than cannon balls or shells. These shutters also, 

 for the reason just given, should be made of a single thickness. The firings 

 show the necessity of concealing entirely, even from the smallest iron missile, 

 their hinges and fastenings. 



