Tide tables commit the river’s movements to paper, predict its future and record its past. I use these complex lines of numbers, dates, times and water heights to fill my diary, temptations to weave my life around, but it is the river that decides when I can search it, and tides have no respect for sleep or commitments. I have carefully arranged meetings and appointments according to the tides, and conspired to meet friends near the river so that I can steal down to the foreshore before the water comes in and after it’s flowed out. I’ve kept people waiting, bringing a trail of mud and apologies in my wake; missed the start of many films and even left some early to catch the last few inches of foreshore. I have lied, cajoled and manipulated to get time by the river. It comes knocking at all hours and I obey, forcing myself out of a warm bed, pulling on layers of clothes and padding quietly down the stairs, trying not to wake the sleeping house.
It is often the tiniest of objects that tell the greatest stories.
I never look at the high-water levels, but I know that a good low tide of 0.5 metres and below will expose a decent amount of foraging space, so I scan the tide tables for these and circle them with a red pen. Spring tides mark the highest and lowest tides of the month. The name comes from the idea of the tide “springing forth” and not, as some mistakenly think, the time of year when they occur. There are two spring tides every month, during full and new moons, when the earth, sun and moon are in alignment and the gravitational pull on the oceans is greater, but the very best spring tides are after the equinoxes in March and September when they can fall into negative figures. They are known as negative tides because they fall below the zero mark, which is set by the average level of low tide at a specific place. A few years ago there was a run of freak low tides that were lower than most mudlarks could remember. Those were the best tides I’ve ever seen. They revealed stretches of the foreshore that hadn’t been mudlarked for over a decade and uncovered countless treasures.
It is the tides that make mudlarking in London so unique. For just a few hours each day, the river gives us access to its contents, which shift and change as the water ebbs and flows, to reveal the story of a city, its people and their relationship with a natural force. If the Seine in Paris were tidal it would no doubt provide a similar bounty and satisfy an army of Parisian mudlarks; when the non-tidal Amstel River in Amsterdam was recently drained to make way for a new train line, archaeologists recorded almost 700,000 objects, of just the sort we find in the Thames: buttons that burst off waistcoats long ago, rings that slipped from fingers, buckles that are all that’s left of a shoe – the personal possessions of ordinary people, each small piece a key to another world and a direct link to long-forgotten lives. As I have discovered, it is often the tiniest of objects that tell the greatest stories.