Chimneys.

Waikato Times, Volume XXV, Issue 2033, 18 July 1885, Page 6 (Supplement)

Chimneys.

A soundly-built chimney vibrates, or swings from sido to side, as a whole, under sudden and violent shocks of wind, and is in reality safer when it does so than when it stands in sullen and unmoved resistance. The vibration indicates that the several constituent parts of the structure are firmly compacted into one coherent, continuous, and, as it were, homogeneous mass, which can sway from side to side like a steel rod or spring, without any tendency to dissolve its continuity and break asunder at some intermediate point. The absence of vibration, on the other hand, means that there is not this integrity of coherence, and that there are, so to speak, fissures of substantial continuity in tho struoture, at which disruptive strain is unavoidably developed. Sudden shocks of wind bursting upon lofty columns of brick-work in such circumstances tend to break them across at the joints where the interruption of continuity occurs. The movements of vibration are there absorbed, and converted into the less desirable condition of molecular strain.