Hazardous Trades. Among the ascertained causes of fire are those which occur in the various workshops where hazardous trades are carried on. These naturally show an increase since steam power has become such a universal aid to nearly every kind of human labor, necessitating furnaces which remain kindled for weeks or months together. Apart from this source of risk, there are numerous trades where such inflammables as turpentine, naphtha, spirits of wine, and combinations of them in the form of varnishes, are in daily use to a very large extent. Drying-stoves afford another dangerous item in the list of fires connected with the trades ; japanners, cabinet-makers, and hosts of others using such stoves as a necessity of their business. Hot-water pipes for heating purposes also represent the cause of a large number of fires, the most dangerous kind being those which are charged with water and hermetically sealed.