A Natural Adhesive: Egg and Honey

It came to my attention while I watched the most recent Sherlock Holmes movie, with Robert Downey Jr. and Jude Law, that he deduced that a limestone slab could be broken, glued together, then break when the glue dissolved with the London rain. Using a “mild adhesive,” a combination of egg and honey, Lord Blackwood was able to break through his grave and walk away.

Assuming that Sherlock Holmes is correct, I have decided to put his logic to the test. I will be testing the hypothesis that an old ancient Egyptian egg and honey adhesive could keep broken rocks together, and then unglue when subjected to water.

Materials:

2 broken rocks (I just found two small ones and broke them apart)

1 whole egg white

1 teaspoon of honey

Stirring stick (I used a butter knife)

Small bowl

Colander

A liquid measuring cup with at least 2 cups capacity

Newspaper

Paper Towels

Procedure:

Outside, I found two small rocks that I broke apart using a rock-on-rock approach. Rock 1 is red-ish and was very crumbly; Rock 2 is black and solid. After breaking them, I washed and dried the rocks. While waiting

for them to dry, I created the mixture of egg and honey.

First, I laid some newspaper down where I was going to work so I would avoid a huge mess. Taking a small bowl, I cracked the egg and separated the yolk and white. Pouring the egg white into a small bowl, I added a teaspoon of honey. Mixing it with the stirring stick/butter knife took about five minutes to combine. Then, taking Rock 1, I covered the broken area in

the mixture, stuck to rock together, and placed aside. On Rock 2 I placed only honey on the rock for comparison. (Pic 1: From left to right: egg/honey mixture; rock 2 and rock 1 after been glued)

After a day and half, I administrated the rain/water test on the rocks. Placing the rocks individually into a sink, I measured 2 cups of water in a measuring cup and poured it into a colander, which was above the rock. If the rock did not separate independently, I continued with 2 cups of water, until the rock(s) separated.

Results:

At first the egg and honey mixture would not merge, it merely separated. However, after mixing if for about five minutes and letting it sit, the mixture combined.

Rock 1: Once the egg and honey mixture was applied to the two sides of the broken areas of the rock, I tried to piece it back together. The mixture did not stick and the rock, even after a couple of hours, never stuck. It seems that the gooiness of the egg white neutralized the stickiness of the honey.

During the rain test, it took only two cups of water to remove any evidence of the mixture.

Rock 2: Instead of using the mixture, as I noted in the results for Rock 1 that the mixture would not stick, I just used honey. Instantly, the two pieces stuck together. However, the honey left a sticky residue and an obvious sign that the rock had been tampered with. After letting the rock sit for a day, undisturbed, I found that the two pieces did stick together, but was easily torn apart under little stress.

During the rain test, it took six cups of water to break apart the rocks independently and to remove the honey from sight.

In Conclusion:

From my final results, I discovered that a mixture of egg white and honey, when applied to two sides of a broken rock, will not stick together but will be easily washed away with water. Using honey, although the rock will show signs of tamper, would be the best way to glue two pieces of rock together. (Pic 2: Final results of what rock 2/1 looks like after been washed)

There were several variables within this test that could have affected the test results. First off, I did no research outside of watching Sherlock Holmes for this experiment. Also, I do not have any limestone lying around anywhere so I could not test that part of the theory.

Perhaps in another experiment I will try different methods with the egg and honey. Maybe using all of the egg, or just the yolk of the egg, would make the mixture sticky; maybe even heating the honey up first. For now, I feel that I have debunked Sherlock Holmes’ theory of how Lord Blackwood, breaking through a thick barrier of rock, was able to arise from the grave.

Side Note: In the movie Sherlock Holmes discovers the egg and honey mixture by licking the limestone. Unlike the movie, I used whatever rocks I could find from my yard, where my dog urinates. So, whether you can taste the honey or egg after the rainfall is NOT something I am going to test. Why? A. Salmonella poisoning as I have no insurance and would love to avoid the possibility of contracting it for as long as possible; B. My dog most likely relieved himself on the rocks, at one point at least.