In 1984 Orwell uses artifacts from the past to layer his dystopian novel with verisimilitude. Namely, he quotes old poems and nursery rhymes, both symbolic language of a past that no longer exists. In this way, the truth seems but a distant memory, like the blurry face of Winston's mother.
Here are two quotes as examples:
This is a nursery rhyme that children used to know:
Oranges and lemons,
Say the bells of St. Clement's
You owe me five farthings,
Say the bells of St. Martin's
When will you pay me?
Say the bells of Old Bailey.
When I grow rich,
Say the bells of Shoreditch.
When will that be?
Say the bells of Stepney
I do not know,
Says the great bell of Bow
Here comes a candle to light you to bed
And here comes a chopper to chop off your head!
Winston Smith: [reciting poem] Under the spreading chestnut tree / I sold you / You sold me
This is Orwell's take on a poem by Longfellow called "The Village Blacksmith":
Under a spreading chestnut-tree
The village smithy stands;
The smith, a mighty man is he,
With large and sinewy hands;
And the muscles of his brawny arms
Are strong as iron bands.
I think the best examples of verisimilitude occur in book two. Throughout this book, Winston believes more and more in the idea that there must be a conspiracy or underground group united against the Party.
When O'Brien gives his personal address and essentially invites Winston over to "learn about the next version of Newspeak" so to speak, Winston believes that O'Brien must be a great part of this conspiracy.
When O'Brien actually has Winston and Julia into his home and tells them that there is a group of them working in rebellion against Big Brother, Winston believes. O'Brien convinces him because he makes it appear so possible and comparable to the life he lives and will continue to live. He notes that people will come and go and that they may never even really meet the people working with this Goldstein.
Lastly, O'Brien gets this authentic copy of the book to Winston so he and Julia can read it. Winston is all into this idea of truth about the conspiracy at this point.