It had snowed steadily for several days so the walk up Coppetts Rd mid Tetherdown to Fortis Green and St James's Ptimary School was part delight and part penance. Like all the boys, I wore shorts, my bare knees were red with cold and a chilbain on one finger itched painfully. My boots were slightly wet so that my legs were ice and cold penetrated everywhere. There seemed no prospect of ever being warm again. By the time we reached school, someone had started a slide in the playground and soon everyone was skimming down the slope, making the slide longer and longer. When one of the older boys stopped the slide, we all kicked fresh snow on to the ice to make it thicker and faster. Everyone began sliding again and running back up the hill. Energetic running was the only way to keep warm. Two or three times that day the teacher made us stand in the aisles between our desks and do vigorous arm exercises. The large coal fire behind its fireguard was drawing well in the cold air, but the heat did not circulate to the back of the room and my chilblain was sore.
The young teacher began talking casually, looking out of the window, pointing out the falling snow. How cold it was. How it melted at a breath. Beautiful, light, fragile. But what would happen if it went on snowing? What would happen to the snow then? What would happen if the snow became thicker and thicker? Right across the playground, up to the window sill, up to the eaves, up to the ridge of the building? The whole school engulfed in fallen snow and above that another school and another, school piled on school and all completely buried, so thick was the snow. A single snow flake was so light that it would be difficult to weigh. But what if the show was half a dozen schools thick? How much would it weigh then? What would happen to the snow at the bottom? Slowly I realised that the snow would have turned into layer upon layer of ice. We would be looking out of the windows into a lump of ice taller than the school. We would live in an ice world, subjects of an Ice King, where everything would glitter like green glass. We would become used to the cold, moving slowly, pushing our way heavily through the ice so that it would take a century to move one step. To make a journey would take ten thousand years.
I was pulled back from this dreaming by the teacher holding up a photograph of a glacier flowing down a valley as a cliff of ice. That whole ice-scape had been made of separate flakes of snow, each one separate, weak and delicate, but now a powerful monster capable of destroying everything in its path. Then he discussed sliding and why we could slide. There was no friction. Once a glacier started moving there was no way to stop it, because if there was no friction, there were no brakes and its weight was irresistible.
The teacher drew a picture of a great ice field stretching from Scandinavia, across the North Sea, to Britain. He described how this snow had fallen round rocks and completely encased them. Small pieces - pieces as big as desks - pieces as big as classrooms with ice all round them, completely wrapping them like currants in a cake. The ice was heavy - almost as heavy as water. Ice was heavy and, because it was heavy it moved down hill. Slowly the ice sheet moved, carrying its load of stones and debris, sliding slowly across the North Sea and into Britain. A great banket of ice sliding on the frozen ground, moving stones, scoring great grooves in the rocks. Nothing could resist it.