Jones' departure was so rash and unplanned that he left nearly everything behind. What was left behind was of significance to the animals, most notably, the pigs. Jones' left books behind. These books were read voraciously by the pigs, most of all, Snowball. It is through these books that Snowball is able to use to his advantage, best seen in the development of the windmill:
The mechanical details came mostly from three books which had belonged to Mr. Jones--'One Thousand Useful Things to Do About the House', 'Every Man His Own Bricklayer', and 'Electricity for Beginners'.
Another example of what Jones left behind is evident after the revolution, when the animals go inside his home and see "how the other half lives:"
They tiptoed from room to room, afraid to speak above a whisper and gazing with a kind of awe at the unbelievable luxury, at the beds with their feather
mattresses, the looking-glasses, the horsehair sofa, the Brussels carpet, the lithograph of Queen Victoria over the drawing-room mantelpiece.
I think that this is where one sees how what Jones left behind casting an impression on the animals. The animals, true to Old Major's teachings, disavow all of these. Yet, at the novel progresses, it becomes clear that the pigs end up appropriating all of what Jones left behind for their own benefit and to further their own control. It is here where what Jones left behind casts an imprint on the mind of the animals, specifically the pigs, as they gain greater control over the leadership of the farm.