A number of flues concentrated, forms a stack of chimneys, as represented in the engraving. Flues, at a distance from the stack, are conveyed to it either in a horizontal or sloping form, as at A and G. The size of flues generally is nine inches by fourteen inches; a space sufficiently large to convey the smoke, but not large enough to be ascended, except by little children, for the purpose of cleansing them.
The plan adopted by the climbing-boy to ascend chimneys is, by pressing his feet, back, and knees against the sides of the flue, by which means he propels or hitches himself up by degrees, having one arm above his head, holding a brush, and the other arm by his side, as described in B. At C the boy is represented as putting his brush out of the top of the chimney-pot, but generally he rattles it with his brush, to satisfy the parties below that he has been to the top. This accomplished, he gradually slides down to the stove or grate.
It has frequently occurred, that boys have, either through fear or inattention, got into the form of nose and knees together, as described at E; sometimes they remain in this cramped and painful position for hours before they are liberated, being totally unable to extricate themselves.