In the adventure novel Treasure Island by Robert Louis Stevenson, the oilskin packet is of utmost importance because it contains a map and directions to the island and to Flint's treasure. Stevenson uses literary devices that are intended to keep readers in suspense and anticipation as the packet is found and later opened.
In chapter 4, "The Sea-Chest," Jim Hawkins and his mother return to their inn, the Admiral Benbow, all alone at night when no people from the hamlet they escape to are willing to accompany them. Jim's "heart [is] beating finely" as they travel the dark road, enter the inn, and find the body of the dead pirate. They put the blinds down, light a candle, and have to pull the key of the sea-chest from around the dead man's neck while "overcoming a strong repugnance." Stevenson uses all of these details to build suspense. While Jim's mother is counting out her money, they hear sounds that indicate they are in danger. In the end, they are forced to flee with less money than they are owed. That's why Jim grabs the oilskin packet, "to square the account."
In chapter 6, "The Captain's Papers," Jim arrives at the home of Squire Trelawney and gives the packet to Doctor Livesey. The doctor obviously wants to open it, but instead he carefully puts it into his pocket until he is alone with Jim and the squire. This is another indication of the packet's importance and builds further suspense in the reader about what is inside.
The squire and the doctor then begin to discuss Flint's treasure, and even before they have opened the packet, the squire agrees to finance an expedition to retrieve it if the packet contains the map. The discussion about the treasure builds the reader's suspense and anticipation even more. Only then does the doctor carefully open the packet, with the help of his medical scissors. Inside are a book and some papers. First they look over Flint's account book, and then they discover the map and directions to the treasure. Immediately the squire proposes an expedition to retrieve it. We see, then, that Stevenson uses a number of literary devices to create suspense and anticipation about the all-important oilskin packet.