Lab Girl (22 page)

I often compare my mass spectrometer to a bathroom scale. Both instruments can be used to measure the mass of an object and report the result according to its place upon a spectrum. On your bathroom scale, the extremes of this spectrum might range from twenty-five pounds to two hundred fifty pounds. When a person steps on your bathroom scale, a spring is mechanically compressed, and the force is transferred to a dial that turns underneath a needle. Numbers have been painted on the dial to increase with increasing force.

A bathroom scale can very accurately tell you whether the object on it weighs about fifty pounds or is really closer to two hundred pounds. Your bathroom scale is great for allowing you to determine the difference between an adult and a child, but it's just not accurate enough to help you figure out the amount of postage needed for your Christmas letter. For that problem, you should use the scale at the post office, which is perhaps a tipping bar that balances perfectly when you slide a weight to the marked position where it exactly offsets the weight of the letter set on the tray.

The bathroom and post office scales are two machines, each one cleverly designed to yield the same type of measurement, the same end through different means. We can keep focusing in on that spectrum: Let's say we want to weigh two sets of atoms, and we'd like to be able to see which set is heavier due to its random incorporation of a handful of extra neutrons. We need to build a machine. The good news is that we only need to build this machine once, since there's no chance that anybody besides us will ever want this thing in their bathroom or government office. This frees us to make it as ugly, silly, unwieldy, and inefficient as we want to—we just need to improvise something that works for us. This is how scientific research instruments are built.

The creative process born from these necessities gives rise to delightfully quirky creations, unique as their creators. Like all art, they are a product of their period and an attempt to address the issues of their age. Also like art, they appear outmoded and antiquated when viewed from within the future that they helped create. Yet there is a singular fascination to be indulged when we stop and stare at the piecework of previous scientists' hands, amazed over the care taken with the peripheral elements, just as we are dazzled by the hundred tiny brushstrokes that magically agglomerate into one small boat on the horizon within a pointillistic painting.

Fifty years ago, scientists such as Ed sculpted their works around huge magnets, which served as the pulsating heart of the eventual machine. The electromagnetic field generated by any magnet acts in proportion to its mass; thus a big magnet creates a field strong enough to pull noticeably differently on different atoms. Their idea then became to accelerate two sets of atoms past the same magnet and then measure how much each was thrown off course as it flew through the electromagnetic field, and from the flight paths determine which one contained a greater proportion of neutrons.

Simple calculations showed how this should work, as the mass-dependent effects of a magnet have been known for hundreds of years. The practical problem of accelerating the particles and measuring the deflection—of actually
doing
it—was worked out by a fairly limited group of researchers working at the University of Chicago, whose students went on to improve the methods at the California Institute of Technology. Their techniques eventually spread to places like Cincinnati and many years later have been automated into the easy-to-drive versions that we use in my laboratory.

Back in those early days, as now, the sample was introduced for measurement as a gas and then ionized before acceleration. Magnetic deflection of the particle beam spewed the sample against a target, and each hit produced a tiny electrical signal. A row of detectors collected these electrical impulses and positioned them on a spectrum whose peaks corresponded to mass. Like a bathroom scale, these mass spectrometers had to be calibrated against familiar items with standard weight, but then they could be used for almost anything that could be coaxed into a gaseous state, including the shells at the bottom of the ocean.

The instrument we were looking at—Ed's old mass spectrometer—resembled a high-tech scrap metal heap and probably weighed at least a ton. Before it was loaded with sample, its metal foyer had to be mechanically pumped free of atmosphere, as did the flight tube. In Ed's day the pumps were little more than a motorcycle engine housed in a steel box, turning rapidly enough to create a strong suction that could be sustained as long as power could be delivered and the noise could be tolerated.

The gas moved through the inlet similar to the way that a barge moves through the locks of a dam, sitting somewhere until the next chamber was sufficiently pumped free of atmosphere. To seal the gas into these waiting chambers, liquid mercury flowed in, provided a wall, and then drained out when the wall was no longer needed. The metallic fluid was almost perfect—chemically unreactive, incompressible, and electrically conductive. There was the small matter, however, of it also being monstrously toxic. Bill and I stared at the beautiful old instrument, knowing that we had no use for it and shaking our heads at its glass saddlebags filled with liters and liters of shiny mercury.

A single drop of mercury from inside an old-school thermometer requires full-on hazardous-materials disposal if broken open. The mere sight of gallon jugs of mercury filled us with awe and our minds bent over the risks that must have been taken while Ed (or, rather, the brilliant Henrik, observed Bill) worked with these substances for decades. A blood-pressure cuff had been modified and added as a means by which to coax the mercury forward and backward, and could presumably be operated with only one hand. The paint on certain knobs was worn from years of careful turning, and the soldering evidenced repeated amateur attempts that finally resulted in too-strong seams. The machine itself provided unsolicited paternal advice to the user, such as “Is H2 off?” and “Turn this one LAST,” written on the valves in red and black permanent marker. A bow of red yarn was tied in one odd corner, maybe to reinforce the memory of a forgettable but necessary step, or perhaps simply as a good luck charm.

After we had stared at the machine from every angle, I observed, “It's a shame to throw this out. Someone should put it in a museum somewhere.”

“No one will,” said Bill.

While we were walking away, I noticed something propped up behind the instrument. It was a one-foot-square piece of wood, with the sharp ends of ten or so screws sticking out of it. Their pointy tips were arranged in a grid, and under each one of them was written the diameter of the screw: one-sixteenth, three-eighths, five-eighths, nine-sixteenths, and so forth. It served a supremely useful purpose, allowing one to quickly assess the size of a stray nut, washer, or bolt, thus helping to diagnose what the hardware had fallen off of or for what it could be used.

“No wonder Ed is in the National Academy,” I said. “We have to take that.”

“No,” said Bill. “It stays here.” I was surprised by his adamancy.

“Are you nuts? It's small and we don't even need to wrap it,” I pleaded.

Bill was looking at it thoughtfully. “No. It's theirs. It needs to stay with Ed.”

“But it's pure genius,” I argued. “It has the power to transform Western civilization and you know it.”

“Relax, I'll make you one,” said Bill. “I promise.”

When we were finished loading the truck, we went to find Ed's office and I knocked on his door. When he opened it, I handed him four sheets of paper and said, “I made a list of what we took, just so you have it.” Ed followed us outside, looked into the truck, and helped us secure everything a second time, and then it was time to go.

“Thank you for everything. It means a lot,” I said, wanting to add something significant but not knowing what more to say. “You've probably even bought me a couple more years before they fire me,” I added with a smile.

“Oh, I have a feeling you are going to be fine.” Ed laughed as he shook his head. “Make sure not to wear yourself out along the way, okay?”

His oblique recognition of my years of effort amplified the poignancy of the situation, and suddenly a big lump gathered in my throat. There in the parking lot, we two scientists conducted a homely ceremony that transferred the tools of his life—his career—to mine.

Ed's suggestion that the Earth's ocean chemistry could be reset completely was a dangerous idea when he was young, and he had stayed up nights to study while the people he knew were watching Joe DiMaggio and arguing about the McCarthy trials. Forty years later his idea was one that I could take for granted as I dared my way into my own ambiguous future. It was kind of tragic, I reflected, that we all spent our lives working but never really got good at our work, or even finished it. The purpose instead was for me to stand on the rock that he had thrown into the rushing river, bend and claw another rock from the bottom, and then cast it down a bit further and hope it would be a useful next step for some person with whom Providence might allow me to cross paths. Until then I would keep our beakers, thermometers, and electrodes in my care, hoping against hope that not all of it would be garbage upon my own retirement.

While absorbed in these thoughts I looked at Ed and was suddenly overcome by an irrational fear that he might die before I saw him again, and I hugged him hard. I couldn't bring myself to watch as Ed shook Bill's right hand goodbye, but I did notice that their handshake had morphed into a bear hug by the time that I had gotten myself into my car and settled behind the wheel.

We got lost while trying to get out of the city, and then once we were finally on the interstate, Bill's voice came over the CB, saying, “Shit, this thing will need gas within a couple of hours. I should have filled up while you were back there playing Goldilocks.”

I chastised him. “Shut up, dwarf. You just be grateful that your job is such a goddamn fairy tale. Not everyone can get away with biting the snow-white hand that feeds them the way that you do.”

“Yeah, well, these trucks don't load themselves. So
you
just remember who your real friends are,” he responded.

I smiled, noticing the slogan on the Pennsylvania license plate of the U-Haul that Bill was driving (“America Starts Here!”), but did not answer. I slipped a disc into the car stereo:
Songs from “Dawson's Creek.”
I held the “talk” button down on the CB's microphone and wrapped electrical tape around it to keep it engaged. Then I set it down carefully, directly in front of one of my car's audio speakers, secure in the expectation that Bill would be driven totally batshit crazy by the third track of those bubblegum pop songs. We got in the slow lane and drove eastward, unsure of who was following whom.

FOR TREES THAT LIVE
in the snow, winter is a journey. Plants do not travel through space as we do: as a rule they do not move from place to place. Instead they travel through time, enduring one event after the other, and in this sense, winter is a particularly long trip. Trees follow the standard advice given for any extended travel within a rustic setting: pack carefully.

Remaining stationary and naked outside in the below-freezing weather for three months is a death sentence for almost every living thing on Earth, except for the many species of trees that have been doing it for a hundred million years or more. Spruce, pine, birch, and the other species that blanket Alaska, Canada, Scandinavia, and Russia endure up to six months of frozen weather each year.

It may not surprise you to learn that the whole trick of survival is not freezing to death. Living organisms are made mostly of water, and trees are no exception. Every cell within a tree is basically just a box of water, and water freezes at exactly zero degrees Celsius. Water also expands as it freezes—the exact opposite of what most liquids do—and this expansion can burst whatever the water is contained within. You see this if the back of your refrigerator is a bit too cold: after a slight frost, your celery is reduced to a limp, watery mess. This is because the cell walls have burst as the cell water froze, and this has ruined your vegetable.

Animal cells can tolerate frozen temperatures for short periods of time because they are constantly burning sugar to produce energy in the form of heat. Plants, in contrast, make sugar, taking in energy in the form of light. If the sun is not strong enough to keep the air above freezing, then the tree is not kept above freezing either. The Earth's rotation is such that the North Pole tilts away from the sun for part of each year, reducing the amount of heat that is supplied to the high latitudes, and this is what causes winter in the Northern Hemisphere.

In order to prepare for their long winter journey, trees undergo a process known as “hardening.” First the permeability of the cell walls increases drastically, allowing pure water to flow out while concentrating the sugars, proteins, and acids left behind. These chemicals act as a potent antifreeze, such that the cell can now dip well below freezing and the fluid inside of it will still persist in a syrupy liquid form. The spaces between the cells are now filled with an ultra-pure distillate of cell water, so pure that there are no stray atoms upon which an ice crystal could nucleate and grow. Ice is a three-dimensional crystal of molecules, and freezing requires a nucleation spot—some chemical aberration upon which the pattern may start to build. Pure water devoid of any such site may be “super-cooled” to forty degrees below zero and still remain an ice-free liquid. It is in this “hardened” state, with some cells packed full of chemicals and others sectioned off for purity, that a tree embarks on its winter journey, standing unmoved through the frost, sleet, and blizzards of the season. These trees do not grow during winter; they merely stand and ride planet Earth to the other side of the sun, where the North Pole will finally be tilted toward the heat source and the tree will experience summer.

The vast majority of northern trees prepare well for their wintertime journey, and death due to frost damage is extremely rare. A chilly autumn brings on the same hardening as a balmy one, because the trees do not take their cue from the changing temperature. It is the gradual shortening of the days, sensed as a steady decrease in light during each twenty-four-hour cycle, that triggers hardening. Unlike the overall character of winter, which may be mild one year and punishing the next, the pattern of how light changes through the autumn is exactly the same every year.

Multiple light experiments have shown that the changing “photoperiod” is what triggers the tree to harden; it can be triggered in July if we fool the tree using artificial light. Hardening has worked for eons because a tree can trust the sun to tell it when winter is coming, even during years when the weather is capricious. These plants know that when your world is changing rapidly, it is important to have identified the one thing that you can always count upon.