Aback is a mariner's term.
In "The Gloria Scott," the Gloria Scott's fore-yard had been hauled aback during the mutiny. This means, it had been swung round so that the wind pressed its sail aft against the mast, in order to slow the ship down.
"The Gloria Scott" takes place with Holmes alone, before his Boswell had come to glorify him. Accordig to Holmes, it was his first adventure, and which proved to him he could make his living as a detective.
I have some papers here," said my friend Sherlock Holmes, as we sat one winter's night on either side of the fire, "which I really think, Watson, that it would be worth your while to glance over. These are the documents in the extraordinary case of the Gloria Scott, and this is the message which struck Justice of the Peace Trevor dead with horror when he read it."
He had picked from a drawer a little tarnished cylinder, and, undoing the tape, he handed me a short note scrawled upon a half-sheet of slate gray-paper.
"The supply of game for London is going steadily up," it ran. "Head-keeper Hudson, we believe, had been now told to receive all orders for fly-paper and for preservation of your hen-pheasant's life."
As I glanced up from reading this enigmatical message, I saw Holmes chuckling at the expression upon my face.
"You look a little bewildered," said he.
"I cannot see how such a message as this could inspire horror. It seems to me to be rather grotesque than otherwise."
"Very likely. Yet the fact remains that the reader, who was a fine, robust old man, was knocked clean down by it as if it had been the butt end of a pistol."
"You arouse my curiosity," said I. "But why did you say just now that there were very particular reasons why I should study this case?"
"Because it was the first in which I was ever engaged."
I had often endeavored to elicit from my companion what had first turned is mind in the direction of criminal research, but had never caught him before in a communicative humor. Now he sat forward in this arm chair and spread out the documents upon his knees. Then he lit his pipe and sat for some time smoking and turning them over.
Sample paragraphs from the story, which is in the public domain:
"'My name, dear lad, is not Trevor. I was James Armitage in my younger days, and you can understand now the shock that it was to me a few weeks ago when your college friend addressed me in words which seemed to imply that he had surprised my secret. As Armitage it was that I entered a London banking-house, and as Armitage I was convicted of breaking my country's laws, and was sentenced to transportation. Do not think very harshly of me, laddie. It was a debt of honor, so called, which I had to pay, and I used money which was not my own to do it, in the certainty that I could replace it before there could be any possibility of its being missed. But the most dreadful ill-luck pursued me. The money which I had reckoned upon never came to hand, and a premature examination of accounts exposed my deficit. The case might have been dealt leniently with, but the laws were more harshly administered thirty years ago than now, and on my twenty-third birthday I found myself chained as a felon with thirty-seven other convicts in 'tween-decks of the bark Gloria Scott, bound for Australia.
"'It was the year '55 when the Crimean war was at its height, and the old convict ships had been largely used as transports in the Black Sea. The government was compelled, therefore, to use smaller and less suitable vessels for sending out their prisoners. The Gloria Scott had been in the Chinese tea-trade, but she was an old-fashioned, heavy-bowed, broad-beamed craft, and the new clippers had cut her out. She was a five-hundred-ton boat; and besides her thirty-eight jail-birds, she carried twenty-six of a crew, eighteen soldiers, a captain, three mates, a doctor, a chaplain, and four warders. Nearly a hundred souls were in her, all told, when we set said from Falmouth.
"'The partitions between the cells of the convicts, instead of being of thick oak, as is usual in convict-ships, were quite thin and frail. The man next to me, upon the aft side, was one whom I had particularly noticed when we were led down the quay. He was a young man with a clear, hairless face, a long, thin nose, and rather nut-cracker jaws. He carried his head very jauntily in the air, had a swaggering style of walking, and was, above all else, remarkable for his extraordinary height. I don't think any of our heads would have come up to his shoulder, and I am sure that he could not have measured less than six and a half feet. It was strange among so many sad and weary faces to see one which was full of energy and resolution. The sight of it was to me like a fire in a snow-storm. I was glad, then, to find that he was my neighbor, and gladder still when, in the dead of the night, I heard a whisper close to my ear, and found that he had managed to cut an opening in the board which separated us.
and
"'It was over them that the great quarrel arose. There were many of us who were glad enough to win back our freedom, and yet who had no wish to have murder on our souls. It was one thing to knock the soldiers over with their muskets in their hands, and it was another to stand by while men were being killed in cold blood. Eight of us, five convicts and three sailors, said that we would not see it done. But there was no moving Predergast and those who were with him. Our only chance of safety lay in making a clean job of it, said he, and he would not leave a tongue with power to wag in a witness-box. It nearly came to our sharing the fate of the prisoners, but at last he said that if we wished we might take a boat and go. We jumped at the offer, for we were already sick of these blookthirsty doings, and we saw that there would be worse before it was done. We were given a suit of sailor togs each, a barrel of water, two casks, one of junk and one of biscuits, and a compass. Prendergast threw us over a chart, told us that we were shipwrecked mariners whose ship had foundered in Lat. 15 degrees and Long 25 degrees west, and then cut the painter and let us go.
"'And now I come to the most surprising part of my story, my dear son. The seamen had hauled the fore-yard aback during the rising, but now as we left them they brought it square again, and as there was a light wind from the north and east the bark began to draw slowly away from us. Our boat lay, rising and falling, upon the long, smooth rollers, and Evans and I, who were the most educated of the party, were sitting in the sheets working out our position and planning what coast we should make for. It was a nice question, for the Cape de Verds were about five hundred miles to the north of us, and the African coast about seven hundred to the east. On the whole, as the wind was coming round to the north, we thought that Sierra Leone might be best, and turned our head in that direction, the bark being at that time nearly hull down on our starboard quarter. Suddenly as we looked at her we saw a dense black cloud of smoke shoot up from her, which hung like a monstrous tree upon the sky line.
