|I haven't yet found anything in either source, Mark. To be honest I haven't yet pulled out my copy of The American Illiad as I don't want to mess with that stack as it's one of the books on the bottom (either it or Grant's memoirs is the bottom book in the stack). Gonna have to prod myself to get it out because of how I have things set up. I can prod myself to get out the Encyclopedia of the American Civil War and The Library of Congress Civil War Desk Reference even though their the fourth and fifth lowest books in their stack, but some of the other stacks I tend to not want to dig down as often on as I should. My being lazy. However, a search on the net turned up this:
In the Wilderness, Va.
Sat. 28th, 1864
I received your of the 22 yesterday was pleased to once more here from home for it had been so long I thought you had forgotten me. I had written three and received none from you. Now I tell you there is nothing that keeps up the spirits of a soldier like hearing from home often. Don’t hesitate to write for fear that I shall not get it, we get mail every day. New York papers the next day after they are printed. Direct as usual Ft. Monroe and I shall get them. The last letter contained one 50 dollar bill which father can you see if he wants or put in the bank for me. Since my last the 7th has been in no fight. Pickett duty comes after every third day then we get shelled and troubled with the Sharp Shooters considerable. Yesterday we moved camp up near to the entrenchments. The Rebs line of entrenchments is in plain sight. The balls of their Sharp Shooters often drop in our camp. Their shells as a general thing go over us unless they burst short but when their open, our artillery dries them up very quick. Our force has been drawn away from here with in a day or two but it is kept very still. There is only enough to hold our works. There is plenty of rumors some think that they have gone around to get in the rear of the Rebs or to make a dash on Petersburg. Others think they have crossed the James RR and gone to join Grant but a soldier is supposed to know nothing. A few days will tell.
This morning we were told that there was two spies in our lines dressed in Navy officers suits. We are to keep our eyes open for them. I hope they won’t get away. Cal and Good are well. I saw Joseph G. night before last, was well. Gen. Butler is with us. I think Gen. Smith was with those that left. Yesterday they brought it from the landing a battery called the Gatling Battery. It is drawn by one horse. It is a neat thing to pick off Sharp Shooters. It is said to shoot one mile accurate it imitates a corn sheller more than a gun. It has six barrels, each four foot long, think and heavy, the ball one half inch the same as a common musket ball. It goes with a crank. The balls are put in a box at the breach of the gun. Then turn the crank and it keeps revolving and shooting as fast and long as desired. Gen. Butler was trying it. Plenty of us went to see him the old gent seemed much pleased with it. After standing around him the Gen. was in a pleasant manner – Well boys you have seen the machine operate now you had better go to your quarters.
As for news probably you get it all in the papers. We only live from hand to mouth. As Father used to say we are always awaiting orders. We know not where the next hour will find us. The news seems to be very encouraging from Grant. I hope he will meet the success for I think the whole thing depends upon him.
I don’t think of anything that will interest you. Give my respects to all enquires. Tell Emily to write a letter. From father would be read with interest.
I suppose it is asked for him to write but he can do the composing and you the writing. Write soon and often.
From your brother soldier,
E. E. Doane
The above transcript I got here: http://www.mqamericana.com/7th_CT_Describs_Gatling_Gun.html
Looking it over it's not a use of the Gatling in a battle but rather come out as a demonstration in the field. There's also this article, http://www.historynet.com/civil-war-guns, in which Dr. Gatling stats that Butler fired on rebels (scroll down, the article is Load the Hopper and Turn the Crank: Rapid-Fire Guns of the Civil War) It does beg the question of if Gatling was actually there to witness the gun being fired or not. But a Lieutenant J.B. Morris of the fourth New Jersey Battery did record this:
Gen. Butler brought one his favorite Gatling guns, which throws 200 balls per minute, in this Battery on Friday, and pointing it through one of the embrasures, began to ‘turn the crank.’ This drew the fire of the Rebs on us, and one captain and a private were severely wounded.
That is in the article. So we do have more evidence of Gatlings in the field. Was Butler firing on the Confederate lines with it and they were responding in kind or was this a demonstration that ticked of the Confederates? I can't really tell. But I suspect as the Gatling was pointed through the embrasure that even if it was a demonstration Butler may have been hoping to hit some Confederate soldiers.