All of these responces from Keith, John and Gerald are excellant and embrace the primary question. As with a Machineguns field of fire on the battlefield, Civil War artillery could not completely defend itself without infantry support. That unsupported artillery on either side, which found itself engaged against an infantry assualt was either forced to withdraw, or be captured. While we known the effectiveness of cannister against standing cardboard targets at a given range was this really the case on the battlefield. Did the Infantry simply stand there like targets? For some reason seasoned Infantry did not seem to fear artillery fire unless they were standing still and the artillery had their range. Then it became unnerving to them.

You read of accounts of cannister ripping great holes in the ranks of the advancing infantry, but these accounts are from the artillery perspective. The immediate effect of the cannister could not have been immediately observed by the artillery crew because of the smoke of their own shot. On the opposite side you don't read in accounts that the cannister ripped great holes on "our ranks" from the infantryman perspective.