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conditions it is believed that greater accuracy can be obtained than with the Coast Artillery gun at normal range of fire. Attention is invited to paragraph S-b, of the attached study of the report, by Captain V. H. Hale, which is concurred in.

Attached hereto is letter from Lieutentant H.W. Cook, to the Chief of Air Service, together with two charts, marked "Exhibit A", and "Exhibit B," which give a comparative accuracy of railroad artillery and bombardment.

Volume of Fire and Rapidity of Effect. (Paragraph 37.) It is agreed that "comparison in these elements is difficult." The fact that bombardment will make its attack in large formations and by successive flights, thus insuring a heavy concentration of fire rather than of successive rounds as employed by the gun, must not be lost sight of. Attention is invited to paragraph E-C, of the attached study of the report, by Captain W.H. Hale, which is concurred in.

Position Finding. (Paragraph 39.) "Sufficient visibility" is essential in terrestrial observation for guns. Haze, light fog, smoke screens, etc. which would make it difficult to observe at long range for Coast Artillery, offer no insurmountable difficulties to the use of Bombardment Aviation. Paragraph 3-d, of the attached study of the report, by Captain W.H. Hale, is concurred in.

Fire Control. (Paragraph 44.) It appears that during the test the altitude at which bombing was to be carried out was fixed regardless of weather conditions. This condition would not obtain in actual operations. The bombardment flight would be so conducted that clouds would not be allowed to interfere. It is possible with the present bomb sight to bomb from any direction, regardless of wind. Attention is invited to paragraph 3-e, of the attached study of the report, by Captain W.H. Hale, which is concurred in.

Vulnerability. (Paragraph 48.) The Ordinance Department gives us the danger zones for various type of bombs, the following:

|Bombs|Danger Zone|
|---|---|
|Fragmentation, 25-lb.|300 yds. radius|
|Demolition, 100- to 300-lb.|1000 yds. radius|
|Demolition, 300-lb. and heavier|2200 yds. radius|

To put coast defense guns out of action it would not be necessary to obtain a direct hit on the gun, but it could be accomplished by the destruction of personnel, plotting rooms, communication lines, battery commanders' [[?]] stations, ammunition galleries, etc. Under such conditions, and referring to the danger sones cited above, it is apparent that coast defenses are very vulnerable.

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