662 THE COLLIERY GUARDIAN. March 28, 1918. [supplement PAGE II.] SIMPLE! CIRCULATOR FOR EFFICIENCY AND ECONOMY For further particulars apply to THE LONDON SIMPLE! ENGINEERING C° L CULLUM STREET LONDON FENCHURCH STREET Telephone— CENTRAL 11029. LANCASHIRE BOILER FITTED WITH CIRCULATOR 1O%to15% MORE STEAM or __ 5%To8%SAVINGii