Periodic Tales

Summary: As a chemist, Sherlock uses the Periodic Table for many reasons. A collection of short fics that add up to a better understanding of what he is and how he reacts to the catalysts in this life.

Elementary

Pertaining to or dealing with elements or first principles. Of the nature of an ultimate constituent, pure, simple, uncompounded. Pertaining to the four elements (earth, water, air and fire); chemistry of or noting one or more elements.

It was one of those rare occasions when John went into Sherlock's bedroom. He tried to respect his flatmate's right to privacy, in the vain hope that he might reciprocate. But, Sherlock's idea of sharing a flat was taken literally, as in everything of John's that was in the flat was therefore available for Sherlock to use.

But, on one of John's occasional mid-week days off, he had decided to do the crossword in the newspaper, and one of the clues was the "a Noble 18". He thought it might be an entry on the periodic table, and he knew exactly where to look for that one. Sherlock had a framed version of the table on his bedroom wall. So, John walked in and found Number 18 was Argon, a Noble Gas. Whatever the hell that is compared to a 'normal' gas. He chuckled; Sherlock could no doubt pontificate on the subject in his public school accent, without realising the aristocratic irony.

Later that afternoon, Sherlock returned from investigating an art theft at a Knightsbridge Gallery. Over supper, he recounted how the case had been solved.

"Really interesting, John; the painting was stolen by the artist himself. Turned out to be a forgery, being sold as the real thing, and he had an attack of conscience- but made it look like a robbery, so the gallery owner could collect on the insurance."

John tended not to accompany Sherlock on art theft cases- not much use for a medical opinion without a body involved. He felt even more like a useless appendage than usual. Another reason was that Detective Inspector Reynolds, in charge of the Met's Antiques and Art Unit, didn't like 'extraneous personnel' on a case. He barely agreed to accept Sherlock's help, but that was more often than not at the special request of the gallery, museum or art owner involved.

So, over a cup of tea, Sherlock finished regaling John with the tale of how the forged painting was discovered under freshly applied gesso in the painter's studio. As ever, John was impressed with the consulting detective's grasp of art, painting techniques and the chemistry needed to know how to remove the gesso without destroying the painting underneath.

"Sherlock, speaking of paintings, why do you have a framed version of the periodic table on your bedroom wall? I mean, it's pretty pointless. You know the data on it backwards and forwards, being a chemist and all. It's not even 'art'. So why hang it up on a wall?"

Sherlock went quiet for a moment. The animation that had accompanied his talk about the case went out of his eyes, and he looked down at the floor. John was surprised; somehow the question had made Sherlock uncomfortable.

After a minute of silence passed, John gave up waiting. He shrugged his shoulders and went into the kitchen to do the dishes from supper. He'd managed to interest Sherlock in eating (Case is over, John, so I can indulge.) As he washed up, he shook his head. Only in Sherlock's head could a normal meal be considered an indulgence. There was so much he didn't understand about his flatmate.

When he came back into the living room and picked up his book from his chair, Sherlock was staring into the fire, his face just looked blank. Three pages into the thriller's story, Sherlock spoke in a subdued tone.

"It isn't a painting, John; it's a print. Of course, I know the periodic table. It's there to remind me of the times in my life when I need to remember it."

John looked over at his friend, hearing the tentative tone and the uncertainty. He put his book down. "I'm not sure I follow- does that mean it somehow gets deleted?"

"No, of course not, it's the one constant- in fact, that's why I need to remember it. When things get …too much. Noise, people, Mycroft, just too much to take in, I need to find a way to shut it all out. So, I start with the periodic table, each element, in order, the atomic weight, the orbits, at what temperature the element will be a solid, liquid and gas- did you know that mercury is the only naturally found element that is a liquid at room temperature? Bromine can be pushed to become liquid at that temperature, but not naturally."

John was used to these little asides- it was as if tangential data just created a little dam in his normal flow of conversation. Without pausing for breath, Sherlock carried on. "I learned the significant compounds related to each of the 118 elements, when they were discovered, and how they are used- it's data, John, hard ordered facts. They ground me, remind me that everything is understandable through chemistry and physics. Going through it all makes me feel safe and in control. There are no lies. Isotopes, allotropes, half-lives- all so… so perfect in its order. It taught me that everything is part of everything else; that nothing dies. It just changes."

Then, almost in a whisper, he said "I need that." Sherlock was looking down at the fire, and the light cast by the flames made his eyes glitter.

John thought about the process. "I've heard of people using mathematics for that kind of…" he couldn't think of a word. 'Therapy' was wrong. But he wasn't a psychiatrist, so he struggled to think of a phrase that would not offend his friend.

Sherlock didn't wait for him to finish the sentence. "When I was little, Mycroft tried to get me to use maths and equations to distract myself. He used to drive me to distraction- I couldn't explain what I needed, but it wasn't sitting there calculating the value of pi to 23 decimal places." He waved a dismissive hand, "Maths is just a means to an end."

"Chemistry is …elegant. It is aesthetically pleasing. So much more detail. And…" here he gave a tiny smirk, "Maths can't explode. Chemistry can."

John smiled. That was Sherlock in a nutshell. Needing to feel safe, yet thrilled by explosions- an enigma, a combination of contradictory elements never quite in a stable state. I'm never bored.