THOMAS A. EDISON 173 cover the possibilities of cement in oonstmction work and he established the celebrated Edison Portland Cement Works, bringing the mannf actare of cement, in all the processes of crashing, drying, mixing, roasting, and grinding, to the high- est perfection by inventing machinery of the most wonderful natare. So great is the faith of Mr. Edison in the value of cement construction that he has likewise taken up the plan of constructing cement houses, made in molds. These molds, made of cast iron with smooth interior surfaces, are taken to the place where the house is to be erected, locked together, and placed upon the solid concrete cellar floor. The cement is poured into the forms, the pouring of the entire house being completed in about six hours. The molds then remain in position for six days while the cement hardens. After that the molds are taken away and the entire house may be seen cast in one piece. No plaster is used, but the walls may be papered or tinted as desired. Only the windows, woodwork, and fixtures need to be put in and the house is ready for oc- cupancy. The molds may be used again and again. Mr. Edi- son believes that eventually it will be possible to put up such a model cement house at a cost of twelve hundred doUars. What a boon to the working man the world over I Another one of Mr. Edison 's inventions which has realized great possibilities is the Edison storage battery. This is now perfected and is used very extensively for automobiles, com- mercial trucks, motor boats, train lighting, and in many other ways. While many people still charge their own batteries, it seems likely that this work will soon be done largely by central power stations. When we consider the vast number of Mr. Edison's inven- tions it seems almost impossible that a single man could have done all this within the brief space of a lifetime, and yet Mr. Edison, though he has been flattered and lionized as few peo- ple have, has remained modest and unassuming. This is il- lustrated by an incident in connection with his application for membership in the Engineer's Club of Philadelphia. In filling out the application blank and stating the particulars as to his
