Excerpt from The Transactions of the Canadian Mining Institute, 1916, Vol. 19 To put it briefly, the boy, having dissolved soap in water, holds a little of it in the bowl of his clay pipe while he blows through the stem. The soapy water forms a film that is distended by the boy's warm breath into a lovely sphere, which is lighter than the surrounding air and therefore rises, while the sunshine undergoes refraction into the colours of the spectrum. When the boy blows through his pipe into pure water, he makes bubbles likewise, but they break instantly. It is the soap that lengthens their life. In the language of physics we say that high 'surface tension' causes the pure-water bubbles to burst immediately, while the addition of soap introduces a contaminant that lowers the tension so as to enable the bubbles to last longer. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.