Heat (2 page)

Also from Lavoisier, with regard to animals that do not eat, that fail to find food: “The lamp would very soon run out of oil and the animal would perish, just as the lamp goes out when it lacks fuel.”

Lavoisier knew, too, about the need for water. He convinced himself that his caloric theory explained sweating. In his mind, warmth meant that caloric was present, a subtle fluid, the embodiment of heat. Water dissolved caloric and carried it away through the skin as sweat, cooling the body. “It is not only by the pores of the skin that this aqueous emanation takes place,” he wrote. “A considerable quantity of humidity is also exhaled by the lungs at each expiration.”

His caloric theory was wrong, but he was right in believing that water is lost as sweat and in the breath, and both contribute to cooling.

Pablo Valencia probably never heard of Antoine Lavoisier, but he knew what it was to sweat. He was once a sailor on the Pacific Ocean, probably on vessels powered by a combination of wind and steam, but by the time he reached forty he had become a grower of watermelons and a prospector, five feet and seven inches tall, weighing 155 pounds. In 1905, the same year that a railroad company auctioned off land to create what would become Las Vegas, forty-year-old Pablo Valencia went into the desert just south of Las Vegas, a desert cooler than Death Valley, wetter, and less deadly.

It was a Tuesday, August 15. Pablo was with Jesus Rios, another prospector. The two men met William McGee, a scientist who mixed geology with anthropology and ethnology, who was camped at a place called Tinajas Altas, or “High Tanks,” a natural trap for the little rain that fell each year. The prospectors were on horses.  They carried six gallons of water, flour made from mesquite seeds or maize, bread, cheese, sugar, coffee, tobacco, and a combination of pressed alfalfa and rolled oats for the horses. They left McGee’s camp at dusk. Sometime before midnight, Pablo and Jesus had covered thirty-five miles. Pablo sent Jesus back for more water, with plans to rendezvous a day later.

That rendezvous never happened. Jesus went back to McGee’s camp for water and returned a day later to report that Pablo was missing. McGee mounted a search of sorts, doing the best he could in such remote land.

Temperatures each day reached the high nineties, except for Pablo’s third day out, when the thermometer spiked at just over 103 degrees. These were temperatures in the shade. But where Pablo went, shade was rare.

By August 18, McGee was losing hope. By August 20, five days after Pablo went into the desert with no more than two days’ worth of water, McGee went back to the routine of his camp. Pablo had either found a way out or was dead.

Early in the morning on August 23, McGee heard a sound coming up the otherwise silent desert gorge in which he camped. It was a low groan carried on the dry desert air. The groan came from Pablo. More accurately, in McGee’s words, the groan came from “the wreck of Pablo,” what was left of Pablo after eight days in the desert.

McGee described what he found in his 1906 paper “Desert Thirst as Disease”:

Pablo’s unwinking eyes were blind. Speech was out of the question. He had long since lost the ability to swallow. McGee poured water onto the skin of Pablo’s face, chest, and abdomen. The skin shed the water at first and then absorbed it, like a dry sponge. McGee rubbed water into Pablo’s nearly dead extremities. After a half hour Pablo could swallow. After an hour he could drink. Within two hours he could eat. At three hours—just after sunrise—he could, with help from McGee, walk the remaining short distance into camp. That evening, Pablo urinated.

On his last day out, Pablo had crawled seven miles over stones and cactus thorns. The journey left him with cuts and bruises that had swollen as he moved slowly through the desert. His hands, wrists, feet, and ankles had swollen, too. Now his breathing was hoarse and sometimes spasmodic, a blending of hiccups and retching that wracked Pablo’s entire body and made him vomit. McGee gave him bismuth and pepsin-pancreatin tablets and simple camp food. After two days, Pablo’s bowels were working. After three days, his vision and voice returned. He seemed to reawaken to the world. He recognized McGee and McGee’s camp assistant. But the spasms kept coming. McGee feared for Pablo’s life.

On August 27, a man named Jim Tucker, along with several friends of Pablo, showed up in camp with a four-horse wagon. They had heard that Pablo was lost and had come out to find and recover his remains. Instead they found Pablo himself, not quite dead. McGee, knowing that Pablo would die if he stayed there in the camp, urged the men to take Pablo to Wellton. “I judged,” wrote McGee, “there was an equal chance of getting the patient alive to Wellton.”

The patient lived. By August 31, he was “deliberately and methodically devouring watermelons.” Within a week, he was gaining weight, coming in at around 135 pounds. He was cheerful, according to McGee, who reported only two permanent effects from the adventure: Pablo Valencia, the former sailor who knew firsthand of raving thirst, of desert thirst as disease, had lost most of his hair, and what remained had turned iron gray.

My companion and I wander the deserts near Las Vegas by car and by foot. They are higher than Death Valley and therefore cooler, cool enough to support cacti, wet enough for shrubs. They are cooler, but not at all cool.

At Red Rock Canyon, we walk through an abandoned sandstone quarry where a steam-powered truck hauled rock to the railroad in the late 1800s. The heat for the steam was generated by oil burners. The water was hauled in or caught in arroyos during the short rainy season or carried from a natural rain trap in the rocks nearby, a place called the water tanks.

We walk past a roasting pit, a shallow depression used by the Southern Paiute and Mojave people and maybe earlier tribes to heat blocks of stone that were then used to cook meat. In summer, it is hard to imagine cooking, but in winter temperatures drop below freezing. Now we walk again under the full light of the sun, over sand and rock and gravel through open country with scattered low-growing plants.

McGee, seven years before he found the wreck of Pablo Valencia, described desert plants. “The only plants able to survive the desert heat and drought,” he wrote, “are water-
​storing
monstrosities, living reservoirs like cacti and agaves.” Small scattered yuccas and branching Joshua trees occasionally stand above the surrounding shrubs. There are barrel cacti, now favorites with landscapers. There are desert trumpets,
Eriogonum inflatum,
with swollen stems that were once used as pipes for smoking Indian tobacco. Creosote bushes are spaced almost evenly across the desert floor, as if part of an orchard, each bush sending up a dozen small trunklets, the branches of these trunklets holding dark green resinous leaflets in winglike pairs. Their spacing—the spacing that gives the desert a sense of order, a sense of openness—comes from the ability of each plant to suck every last drop of water from the soil reached by its shallow, outward-running roots.

A little higher, where the flat desert floor begins to rise, there are mesquite trees with leaves that resemble those of peas and taproots that drill down as far as 150 feet to find water. Mesquite seedpods can be dried and ground into a coarse flour called pinole, possibly the flour that Pablo Valencia and Jesus Rios carried into the desert.

We walk upward between rock walls that frame a corridor with a floor of sand as fine as sugar. We find a ponderosa pine, gnarled and hard bitten by wind and heat and lack of water and the rocky ground on which it struggles. The pines are remnants of earlier forests that thrived here in a cooler time, all but disappearing near the end of the Pleistocene, leaving only a few straggling colonies hanging on in shaded canyons, struggling to survive in a warmer world.

We find what at first glance I mistake for saltbush, its leaves narrow and thick, suggesting an
Atriplex
of some kind, but with a second glance I see that I am wrong. I see acorns. It is a canyon oak, adapted to the desert but as much an oak tree as the great shade tree live oaks of Florida and Georgia, as much an oak as the red oaks used for ship planks and the white oaks used as hanging trees, all species of the genus
Quercus.
And coming over a rise and downward into a sand flat, I see what look like willows, plants that go by the common name “desert willow” but are not willows at all, not even in the willow family, the Salicaceae. They are
Chilopsis linearis,
of the family Bignoniaceae. The Spanish common name is accurate:
mimbre,
meaning “willowlike,” because their leaves are long and narrow, like those of willows, and their trunks are tall and slender and seldom straight, like those of willows. And, like willows, they love water. Somewhere below the ground here, not too far down, the dusty ground must be damp.

We move farther downslope, losing a few feet of elevation, and break out of the willowlike thicket to stand in a quarter acre of rushes, two feet tall, some dried and brown, others a lush green that speaks of recent water. The ground itself is dry. We are standing in the dust of a bone-dry marsh. A crust of algae separates my boots from the loose sand floor of the canyon.

I pick up a handful of the crust. Intact, it might make excellent tinder, but between my fingers, with the slightest grinding motion, it turns to dust.

This is the sort of place where a man like Pablo Valencia might desperately dig, looking for water. If lucky, he might find moist sand, something to put in his mouth. If he were extremely lucky, he might find enough water to wet a bandana, and he could squeeze the water from there into his mouth and then hold the damp cloth between his lips, sucking in an extra hour of life.

I measure the temperature of rock surfaces. Beneath plants, shaded by leaves and branches, the rocks and sand are cooler, at eighty-nine degrees. Between plants, bare rocks exposed to the sun come in at 138 degrees. But here is an oddity: the tops of plants, fully exposed to radiant heat from the sun, baked to the same extent as the rocks on the desert floor, do not exceed 105 degrees. They reflect light from the sun but also cool themselves by giving up water. Inside their leaves and stems, water molecules dance wildly with the energy of heat. A pore opens—a stomata, whose main purpose is to allow carbon dioxide into the plant. When the pore opens, water is lost, taking with it the heat that made the water molecules dance. The same physics cool our bodies when we sweat. The water leaves the plant or the person, turning to vapor and taking with it a measure of heat.

When a person sweats, if the sweat does not dry, it does not cool. In a Louisiana salt marsh, with humidity over 90 percent, where mildew outruns evaporation, sweating is of little use. Here in the desert, sweat dries. Sweat dries quickly, pulling heat away, but also sucking away water needed for survival.

I point my infrared thermometer at my companion’s forehead. She comes in at ninety-one degrees, normal for skin temperature.

For the plants, as for Pablo Valencia, life is about heat and water. The plants that cannot survive the open heat or the scarcity of water live in shaded canyons and at higher elevations and near water traps. Some of the desert plants that grow only near water—the water spenders, as they are sometimes called—have to deal with the salts that accumulate near desert springs. Some would be at home in salt marshes. There is pickleweed,
Allenrolfea occidentalis,
also known as iodine bush, a plant that looks like the glasswort of the Gulf of Mexico coast but grows taller, forming dense shrubs. Its green succulent stems taste like salt. They are, in fact, full of salt. When a stem becomes so salty that it can no longer survive, the stem dies and is shed, and the plant itself survives.