PART OF THE Summer Reading ISSUE

‘By the time John joined the fertiliser factory in Leith, phosphate rock arrived in slow boats from Africa. A fine golden powder mixed with small pebbles and the occasional bullet.’

Edinburgh has long been an ideal holiday destination, even with our plethora of crime writers dedicated to exploring the city’s seedier side. Fiona Erskine joins the ranks to bring us a murder-mystery, set in Leith, that delves in the capital’s industrial past.


Extract taken from Phosphate Rocks: A Death in Ten Objects
By Fiona Erskine
Published by Sandstone Press


Silver Bullet

In the police interview room, a telephone rings. Brrring. An old-fashioned bell, it echoes round the bare room. Detective Inspector Rose Irvine answers.

‘Yes?’ she barks and then frowns. ‘Yes, sir. Right away, sir.’

She puts down the receiver and checks her watch.

‘We’ll break for lunch,’ she says.

John steps out to breathe.

He marches east to Lothian Road, dropping behind St Cuthbert’s into Princes Street Gardens where the path curves in the lee of the castle. Traversing the Mound, past Waverley Station, he looks up at the big clock over the North British Hotel and adjusts his watch as the One o’Clock Gun fires. Ignoring the pain from his arthritic hip, he continues to the top of the Calton Hill where Edinburgh unfolds before him: the Pentland Hills to the south, the Ochils to the north, and the silvery Firth of Forth snaking through a broad valley in-between.

The only ship in Leith docks now is the Royal Yacht Britannia on a permanent mooring. No cargo boats. He narrows his eyes to try and make out the remains of a factory.

For decades, John monitored production from the top of Leith Walk. He knew in advance what sort of shift to expect, making an accurate assessment by the colours in the sky. A thin streak of orange reassured him that the nitric acid plant was producing aqua fortis, a blue/grey haze above the Nitram tower told him that little white prills were rattling down inside, and the height of white steam soaring in puffy clouds from the tallest chimney gave the rate of granulation.

He always arrived early for the shift handover, walking round the plants before his own crew clocked on. He made sure that no one from the retiring mob disappeared for an early shower or left their logbook incomplete. Then he waited at the gatehouse for his morning or evening ‘kiss’. As each arriving worker came towards the bars of the turnstile, John pressed his gaunt face against the other side and barred entry until they gave him a whiff of their breath. Those with nothing to hide endured the ritual without complaint. Others, men still recovering from a bad pint or who had taken a whisky breakfast with the stevedores, might dissemble or protest. His long bony fingers would reach out, pinch a nose through the bars of the cage until they opened their lips. They either breathed onto his nose or backed away to call in ‘sick’.

John possessed a finely tuned chromatograph in his nostrils. He could perfectly calibrate and overlook a single evening pint before night shift, although he was less forgiving about morning spirits. He encouraged the progress of the recovering alcoholics, monitoring the pungency of sweet ketosis, berating them when they fell off the wagon. Bad oral hygiene, a love of garlic, even super-strong Trebor mints did not interfere with the accurate assessment of blood alcohol level.

John took his first cup of tea standing at the window to keep an eye on the departing shift. He then walked round again to instruct each member of his own crew individually. Although John scanned the shift logs (hardbacked, narrow-lined books, black with red spines) and glanced at the numbers scrawled onto pre-printed A3 sheets, he worked mainly by intuition: the opacity of the yellow haze over the sulphur melter, the taste of acid in the vacuum ejector hot wells, the thickness of ice on the spheres, the texture of warm fertiliser granules as he ran them through his hands, the pitch of the whistle from steam billowing into the sky.

Once things were settled and he had personally instructed each team member on what he expected of them, he returned to his office. On day shifts, he walked to the canteen, arriving just as it opened. On nights, John sat alone at his desk and ate two white bread and marmite sandwiches followed by the second of twelve cups of tea. The only concession to the unnatural working pattern was a Tunnock’s caramel wafer at two in the morning when his body clock was screaming for sleep.

Today the air is clear. Wispy white clouds snake across a pale blue sky. From Calton Hill, John gazes down over Edinburgh, following the road to Leith. Nothing remains of the tall factory structures. The demolition crew flattened everything above ground before they started excavating.

How can a complex manufacturing plant, once the lifeblood of Scottish agriculture, decades in construction, disappear in a matter of days?

John turns away with lead in his heart. The physical structures are gone, but what of the stories? The close-knit community? The livelihoods of a ragbag of assorted men?

And a few women.

John takes the bus back to Torphichen Street and limps into the interview room. Detective Inspector Rose Irvine is waiting for him. Her morning scent of roses is now mixed with a hint of caramelised tomato and roasted onion.

‘Pizza for lunch?’ John asks.

She nods and checks her white shirt for telltale traces, frowning up at him when she finds none. ‘Ready to continue?’


He inhales deeply before picking up the next object: a silver necklace. The pendant is barely recognisable as a bullet; the base has splattered into the petals of a flower. The links of the fine silver chain spill through his fingers as he hands it to the detective inspector.

She takes it and holds it up to the light. ‘Do you recognise this?’



‘It’s from Jordan,’ he says.

‘A person or a place?’

He frowns. ‘The Hashemite Kingdom of Jordan.’

‘In the Middle East?’


‘So how did it get to Scotland?’

‘In a cargo of phosphate rock.’

‘And who did it belong to?’

In the police interview room, John turns to the window, feigning interest in a flock of birds swooping past, and remembers Polly.



Elemental phosphorus, nicknamed the devil’s element, is highly flammable and will spontaneously combust in air. First isolated in 1669 by Hennig Brand, it is named from the Greek phosphorus mirabilis, meaning miraculous bearer of light. Brand was a German alchemist looking for gold in urine (as one does). He discovered instead that, if you boil down twenty litres of urine, you can get one gram of this strange, volatile substance that glows in the dark and burns with a cold radiance.

Phosphorus makes matches, fireworks and incendiary bombs sparkle. It’s also highly toxic – used in rat poison, herbicides, insecticides, chemical warfare and other forms of murder. However, once phosphorus is combined with oxygen and converted to phosphate, it becomes stable, non-toxic and has the power to regulate all life on earth.

The average human body contains over three kilograms of phosphates, most of it in your bones as crystalline hydroxyapatite. The hard, dense enamel of your teeth is formed from another phosphate, fluorapatite. Every single cell in your body carries your genetic code, and the backbone of each strand of DNA or RNA is made from alternating phosphate and sugar groups. Inside the mitochondria, the powerhouses of the cell, another phosphate compound, ATP, regulates the energy flows in our body, with one of the triple phosphates breaking bonds to release energy, leaving a double phosphate (ADP) behind. The energy from food is used to regenerate the phosphate–phosphate bonds and the human body recycles its own weight in ATP every day.

Some phosphates in your body are excreted, in urine and faeces, and need to be constantly replenished. There is no phosphate in the air you breathe, very little in the water you drink, and so you ingest it with your food. Animals get phos­phate from the plants they eat, and plants get phosphates from the soil.

Phosphorus helps plants ‘fix’ carbon dioxide from the air, as part of a series of reactions called the Calvin cycle. Using the energy from the sun, plants turn gaseous carbon dioxide into glucose and other sugars during photosynthesis with the help of the most abundant enzyme on earth: rubisco, a phosphorus-containing enzyme that acts as a catalyst during the first major step of carbon fixation. Phosphorus regulates the energy which sustains life.

But there’s a constant need to replenish this element. Very little phosphorus is recycled. Apart from slaughterhouse products such as bonemeal, the concentrations are too low for practical recovery. Farm animals and crops take more phosphate out of the ground than they put back, so the balance must come from elsewhere.


In the middle of the ocean, an uninhabited island rises from the sea. The tip of an extinct volcano, its sheer cliffs plunge vertically to the crashing waves, but the rocky crater provides shelter and a resting place for migrating birds: cormorants, pelicans and boobies. The birds feed, sleep and fly on, leaving a little something behind.

Guano is the accumulated excrement of seabirds and bats. A Spanish corruption of the word ‘wanu’ from Quechua, an indigenous language of the South American Andes, it originally referred to any form of dung used as an agricultural fertiliser.

In the harsh desert land that makes up much of Peru, indigenous people were already using guano to enrich the soil five thousand years before the Spanish arrived. The Inca emperors valued the precious material so highly that they restricted access to all but a few licenced collectors and punished disturbance of seabirds with death.

The Prussian explorer Alexander von Humboldt wrote about the incredible fertilising properties of guano in 1802. In 1813 English chemist Humphry Davy highlighted the special efficacy of Peruvian guano in his book Elements of Agricultural Chemistry. The book became a bestseller, and so did guano.

In a canny move, the Peruvian government nationalised its guano resources and, in 1856, used the revenue to abolish slavery and free twenty-five-thousand slaves.

With prices rising, a search for new sources of guano began. Explorers targeted islands in dry regions, where the valuable nutrients left by seabirds remained in situ, instead of leaching out with every rain shower.

Ichaboe Island off the Diamond Coast of Namibia is one of the most densely packed and important breeding sites for seabirds. Safe from mainland predators, cormorants and penguins, gulls and oystercatchers, terns and gannets nest on the island. Each year, fifty thousand birds share the low-lying island. Over time, they built up guano deposits seven metres deep.

The demand for guano became so fierce – the white gold rush – it led to America’s first imperialist experiment. In 1856, the Guano Islands Act was passed, encouraging American citizens to claim land for the United States.

Whenever any citizen of the United States discovers a deposit of guano on any island, rock, or key, not within the lawful jurisdiction of any other Government, and not occupied by the citizens of any other Government, and takes peaceable possession thereof, and occupies the same, such island, rock, or key may, at the discretion of the President, be considered as appertaining to the United States.

About one hundred guano-rich, uninhabited islands in the Caribbean and Pacific oceans were annexed by the USA. The labourers shipped in to extract the guano worked in terrible conditions. A quarter of a century after the abolition of slavery, little had changed and in 1889, the Navassa Island Rebellion led to the deaths of five white overseers. The trial of the black contract workers from Maryland went to the US Supreme Court, and death sentences were eventually commuted.

A new source of phosphate was required.

By the time John joined the fertiliser factory in Leith, phosphate rock arrived in slow boats from Africa. A fine golden powder mixed with small pebbles and the occasional bullet.


Phosphate Rocks by Fiona Erskine is published by Sandstone Press, priced £8.99.

You can watch Fiona Erskine taking part in BooksfromScotland’s Scottish Books Long Weekend over on Publishing Scotland’s YouTube channel here.

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