However, the roof was the best part. Two children were made to stand facing each other in front of the class to act as the two opposite walls. The teacher stood on a chair between them and put his hands on their heads. His arms sloped down like the rafters of a roof and, as he pressed dlown, the force along his arms pushed the 'walls' outwards. The children were gently pressed backwards on their heels as the 'roof'' pushed downwards and outwards.
Suddenly the weight of the roof became clear. Huge baulks of timber suspended over our heads, trying every minute of the day to fall. Blown by gales, soaked by rain, why did the roof stay up and why, above all, did it not push out the tops of the walls? The teacher tied a length of string between his two wrists so that his straight arms and the string made a triangle. Try as he might, his arms could not stretch further apart than the length of the taut string. Now when he stood on the chair and pressed down, his weight rested on the top of the children's heads: they were not pushed outwards. They were pushed downwards. The children were walls. They would have been toppled sideways if the roof beams had been able to spread out, but were able to hold great weights which merely pressed straight downwards.For me thereafter the roof was a living thing, with its great rafters pressing down and trying to move outwards, but the tie bars holding them firmly together in a grip literally of iron
. It was only years later, teaching in modern classrooms with their low ceilings, that the reason for the high open roof, without a ceiling, became clear. I had first seen the high roof in 1925, when I was eight. A number of years earlier Aunt Jessie had developed tuberculosis and had had to go to the clean air of Mansfield to recover. This she did over a long period of years, but never returned to live in the smoggy air of London for fear that the infection would recur.
Tuberculosis was rife before the Second World War. Almost every family knew of someone who suffered from the disease, or had died of it. The only known cure was fresh air. Sixty children in one classroom could rapidly infect each other, so each child needed plenty of fresh air which was changed regularly. Therefore London schools, like my old Stroud Green one, were built with very high ceilings and windows on each side to give ventilation. Medical Officers of Health were perpetually writing about the 'Cross-draught Theory'.
In 1840 there were 4000 deaths per million from tuberculosis. Slowly better living conditions, better food, and the cult of open-air exercise, reduced this but, by the time the tuberculosis bacteria was identified in the 1880s, there were still 2000 deaths per million. There was then no prospect of an early cure and though the death rate had been halved, this was only part of the story. TB made it difficult for the patient to earn a living: there were long periods of sickness at home or in hospital. Patients had to be supported by their relations since there was no free health system and no unemployment pay, so one tuberculosis patient could bring distress to a whole family.