Show THE ELECTRIC SIRENS PLACE AS A COAL MINE WARNING SIGNAL what perhaps is one of the most outstanding of the many problems problem confronting coal mine operators relates F A orth of the federal electric co chicago is that of notify in ing the works on a moments notice that there is no work for the day if the workers come to the mine and have not been previously notified that there is no work the operators must p pay ay them I 1 two hours wages that is the a agreement 9 ree between the 0 operators pera tors and the men at most coal 4 mines mines many gustand ing coal mines have solved the V problem with the electric siren a tower installation of which is illustrated here its wierd penetrating ratina screech carries the no work message to all of the workers within a radius of one and one half to two miles they do not i trudge to the mines only to find that there is no A t work and the operators save the two ho hours urs wages in addition the electric siren is used to awaken the workers in the ane mo morning bornino rnino b to tell them when it is time to start to WO work rk dur and to sound the start and quit work signal too it is is used ing work hours as a fire and general emergency alarm these the federal electric siren most generally used in ill J and five fileo p capacities are the one third one three under er sirens the one third horsepower siren is used on u de ground locomotives and other places where a signa w is device having a sound radius of only a quarter of a alle theone desired the one horsepower siren consists of three of ol 01 a rid third horsepower sirens sirens moun mounted ted on a tri triangular annular base bas hav is usually erected in a stationary position where a siren hot se third inga inga sound radius greater than that of a one tin ra thill is power siren and less than that of a five horsepower required most the three and five horsepower sirens are the ones on sit 0 11 a rk g generally C used for sounding the start and quit vo 4 no work signal and fire and general emergency emerge t 5 the three horsepower siren is of single horn colstr con and the five horsepower unit is of do double ab ble horn colstr con sirens an additional feature of the three and five horsep horse used is that they may be e 11 had ad to sound code sia signals nals T nade jg to 10 be to warn of fire or accident they can therefore D b code tell at the same time where the fire or accident i is s Y J |