Herb -

To add to your answers. I think "horse artillery" has been adequately explained.

As also explained, "heavy artillery" was normally in fixed fortifications and was not normally in large battles until the fighting reached their area such as Richmond/Petersburg in 1864/65.

Lincoln was almost paranoic about the safety of Washington DC and ,during most of the war, kept large numbers of troops , including much heavy artillery, near the capital.

However, when Grant came east in the spring of 1864, he soon decided much of this manpower was wasted in the bars and fleshpots of Washington. He transferred many of these units to the front around Petersburg and used them as infantry. They, however, retained their designation as "heavy artillery".

Vickburg, Savannah. Charleston, Mobile and other places employed much heavy artillery.

-- Ken