Especially in the US we're used to finding an eraser on the end of a pencil. The concept of an attached eraser was first conceived by Hyman Lipman in 1858 (fact: National Pencil Day is the day that the patent was filed, March 30th). Lipman's idea of an attached eraser is a far cry from what eventually became the norm as it cased eraser into its core instead of attaching it to the end:
Shortly after the patent was filed, Lipman sold the it for $100,000 (a fortune in the 1860s). Ten-ish years later while in litigation with A.W Faber over infringement the supreme court threw out the patent, deeming it invalid.
It wasn't until the early 1900s that the ferrule (the metal thing that attaches the eraser) as we know it came to be. They were first made of brass and were very elongated. I'm not entirely sure whether this was a decision based on style or function but I'd be willing to bet it was a bit of both--the longer ferrule was extra secure but also incredibly beautiful. With the introduction of the Eberhard Faber Van Dyke pencil--the first to feature the flat ferrule that the Blackwing 602 made famous--many other pencil manufacturers in the US follow suit and began getting really creative with their ferrule designs.
So much competition arose from this new idea of having a fancy ferrule that the National Bureau of Standards set up guidelines in the 1930s for how pencils in the US were to be priced based on their specific physical characteristics. This didn't stop larger brands like Eberhard Faber and Dixon from making higher-end versions until a bigger problem arose in 1939 with the start of WWII.
It didn't come as a complete surprise to the pencil industry that the outbreak of WWII would cause major production issues. In fact, the American Lead Pencil Company predicted the impending metal shortage and came up with a solution before the war even started: plastic and cardboard ferrules. Both were relatively easy to manufacture and new plastic technology made it inexpensive as well. This even allowed pencil companies the ability choose what color their ferrules would be, as it was easier to color plastic and paper than it was to color brass. The three best selling #2s made strategic choices for their new looks: Ticonderogas were made in green with a yellow stripe, Venus in blue with a light blue strip and Mongol in a black with a yellow strip. Once the war was over and access to metal was restored to the pencil industry many of these brands still kept their new color schemes. This became especially easy in 1964 when J.B. Ostrowski patented the aluminum ferrule, which was cheaper and easier to color. He designed it to have two horizontal bands and lots of vertical ridges to keep the soft aluminum from disfiguring--the exact same ferrule design we're used to seeing even today.
The ferrule is a vital component of a modern pencil and an interesting form of brand identity. Though the attached eraser is still a largely American pencil feature, just about every pencil manufacturer in the world makes some version of it. The days of elaborate brass attachments may be far behind us but we should consider ourselves lucky to still have some version of Eberhard Faber's famous flat ferrule and a few slightly quirky ones, like the purple-ish Japanese ones or the super recognizable Ticonderoga green. Keep an eye out for ferrules of pencils past--not only do they make wonderful collectors items but they also are great indicators of their period of production.