In chapter 12 of The Just Men of Cordova (1917) by Edgar Wallace, the author is describing the situation of the odds of two horses, Timboilino, the owner of which is Isaac, and Nemesis, the owner of which is Gresham, after they tied and before the run-off between them.
Black reassured his friend, Isaac, that Timbolino will win easily.
Somewhat reassured by his companion’s optimism. Sir Isaac awaited the conclusion of the run-off in better spirits. It added to his assurance that the ring took a similar view to that which Black held. They were asking for odds about Timbolino. You might have got two to one against Nemesis.
But only for a little while. Gresham had gone into the tea-room with the girl, and was standing at the narrow entrance of the county stand, when the cry, “Two to one Nemesis!” caught his ear.
“They’re not laying against my horse!” he exclaimed in astonishment. He beckoned a man who was passing. “Are they laying against Nemesis?” he asked. The man nodded. He was a commission agent, who did whatever work the young owner required. “Go in and back her for me. Put in as much money as you possibly can get. Back it down to evens,” said Gresham decidedly.
He was not a gambling man. He was shrewd and business-like in all his transactions, and he could read a race. He knew exactly what had happened. His money created some sensation in a market which was not over-strong. Timbolino went out, and Nemesis was a shade odds on.
Then it was that money came in for Sir Isaac’s horse.
Black did not bet to any extent, but he saw a chance of making easy money. The man honestly believed all he had said to Sir Isaac. He was confident in his mind that the jockey had ridden a “jolly race.” He had sufficient credit amongst the best men in the ring to invest fairly heavily.
Again the market experienced an extraordinary change. Timbolino was favourite again. Nemesis went out—first six to four, then two to one, then five to two.
But now the money began to come in from the country. The results of the race and its description had been published in the stop-press editions in hundreds of evening papers up and down England, Ireland and Scotland. Quick to make their decisions, the little punters of Great Britain were re-investing—some to save their stakes, others to increase what they already regarded as their winnings.
And here the money was for Nemesis. The reporters, unprejudiced, had no other interest but to secure for the public accurate news and to describe things as they saw them. And the race as they saw it was the race which Sir Isaac would not believe and at which Black openly scoffed.
The last event was set for half-past four, and after the field had come past the post, and the winner was being led to the unsaddling enclosure, the two dead-heaters of the memorable Lincolnshire Handicap came prancing from the paddock on to the course.
The question of the draw was immaterial. There was nothing to choose between the jockeys, two experienced horsemen, and there was little delay at the post. It does not follow that a race of two runners means an equable start, though it seemed that nothing was likely to interfere with the tiny field getting off together. When the tapes went up, however, Nemesis half-turned and lost a couple of lengths.
“I’ll back Timbolino,” yelled somebody from the ring, and a quick staccato voice cried, “I’ll take three to one.”
A chorus of acceptances met the offer.
Actually I don't have much knowledge about the horse racing, and I searched a lot about the possible significance of these bolded words, but I didn't get them.
Does "ask for odds about" = "want to know the odds or want to bet on", and what did the author mean by "You" in "you might have got two to one against"?
How did the odds become "Two to one Nemesis" although he said "two to one against Nemesis" in the previous statement? ِAnd I found that "lay against" mean "bet on the losing of", so why was he astonished?
How did Gresham say: "They’re not laying against my horse?" although it was already said "two to one against Nemesis"?
Does "back it down to evens" mean "back it till the odds become evens"? And why he wanted to back the odds to evens?!
Why didn't the author say simply "three to two" instead of "six to four"?
How could someone say "I’ll take three to one"? I mean could an ordinary man set the odds by himself?!
I know it's a long and complicated question, but I really can't understand it by searching!
Thanks in advance.