So in my most recent Gilmore Girls recap, I take a quick tangent to wonder why construction people always lick their pencils before they write.

Not one, but two emails have come in today to answer my question.

From Laura:

Hey there,

You offered up this observation on your most recent Gilmore Girls recap. Those are the kinds of questions that keep me up at night. My dad used to do this, too, and he always told me it was to make the line darker. He did it when marking wood, though. I did a bit of research and got this off an MIT website:

A writer to the “How & Why” column in The Boston Globe asked why so
many people, before putting pencil to paper, lick the tip? “Is there something about saliva that makes graphite flow better?”

For the answer, which was “yes,” the Globe turned to Dr. Jack B. Howard, professor of chemical engineering, who said he himself licks his pencil tip at times.

“If the lead were truly graphite, then wetting it would probably not make a difference,” said Dr. Howard, whose research includes work on graphite and other forms of carbon. But in pencil leads, he said, “the graphite is actually a mix of graphite and some clays,” which are added to control the hardness of the lead.

“My observation is that wetting the pencil allows you to get a darker line,” Dr. Howard said. “There’s a softening of the material, some absorption of moisture into pore spaces that makes a mix that will rub off more easily. If it were pure graphite, there would be no pores to let the moisture in.”

Is it a safe practice? Yes, said Dr. Howard, the graphite-clay mixture is “perfectly innocuous.”

Just thought I’d share. I didn’t see where anyone had said anything about it on the forums. Oh, and if you’ve never been there, www.straightdope.com has answers to all kinds of questions like that. I
love that site.

And from “Lacrosse Dude”:

The tradition of pencil licking goes way back to the days before portable ink pens existed. In situations where you needed to make a permanent mark, but in a less than ideal situation (in my families case…a payroll officer for the first Canadian transcontinental railway) that would make using a nib pen and bottle ink..well, messy you used an indelible pencil. It looked much
like a regular pencil, but had no graphite (lead) in it – rather something
that was purple – but required it to be wet to write. So you had to lick the tip (or dip it in water) before it would write in a permanent fashion (which was vital for accounting of payroll).

So my relative had a purple stained tongue for a good portion of his life.

Another possibility, if you are doing fine brush work with an art brush, you will lick it to resharpen it…that is why the (mostly women) who painted the radium on the gauges for world war 2 air plains got some very interesting cancers of the mouth.

Why it stuck around to modern days is a bit of a mystery (although, only by car salesmen and tradesmen), I have never once seen an indelible pencil in my life – my father told me about them once when telling me about his grandfather.

So ends the lecture.

You guys know everything.