Sir George Cayley, an English philosopher, born at Brompton, Yorkshire, in 1773, died Dec. 15, 1857. He undertook the analysis of the mechanical properties of air under chemical and physical action, and his papers on the subject gave rise to many experiments on the navigation of balloons. His experiments on the steam engine led to his invention of the air engine. His discoveries in optics were followed by the invention of an instrument for testing the purity of water by the abstraction of light. He was also the inventor of an ingenious arrangement for obtaining and applying electric power to machinery, He was one of the original promoters of the polytechnic institution at London. Toward the end of the last century he applied to his extensive estates in Yorkshire a new system of arterial drainage. He was also the father of the cottage allotment system. As a politician, he took a prominent part in the election of liberal members of parliament. Upon the passing of the reform bill he was himself chosen member for Scarborough, but on account of age he soon retired.