107 
than that of the second target, is to the European one, and 
how thoroughly he had, at that early day, mastered the sub- 
ject. He had indeed perfected the embrasure so far as it 
could be done with masonry alone 
But the quantity of small tiation which even that em- 
brasure would receive is dangerously great, and would be 
much diminished if the funnel form of the mouth could be 
done away with, and the throat reduced to an absolute mini- 
mum. ‘This could be accomplished only by the use of iron, 
and the conclusions I have just quoted furnish the data 
necessary to its successful application. 
The throat (still placed two feet back from the outer fin 
of the wall) being formed of iron plates, it became practi- 
cable to cut away the flaring surfaces of masonry, so as to 
present others parallel or perpendicular to the face of the 
wall, and by this change of form to exclude all missiles not 
directed within the limits of the throat itself. Still more 
completely to accomplish the object, wrought-iron shutters of 
two inches thickness (as determined by the experiments) 
were applied, by which, except at the moments of aiming 
and firing, the embrasure was entirely closed. , 
Such is the history of the casemated battery and case- 
mate embrasure in the United States. We have seen that 
the perfection to which they have been brought is due to 
General Totten, and to General Totten alone. Nor is it to 
= experiments which I have been describing, laborious, 
ilful, and thorough as they were, that we may solely at- 
thats such results. We must look back to the time when, 
a First Lieutenant of Engineers, he saw and aided in the con- 
struction of our first casemated fort, and when he, fully ap- 
Preciating its merits and recognizing the defects which a 
disregard and want of appreciation of the illustrious projec- 
tor’s own principles had entailed upon it, set himself to the 
task of enhancing the one and correcting the other. 
