Notes on mine signalling systems

I notice in Mr. Gould's paper he mentions single-stroke bells. I think anybody who uses single-stroke bells in mining work is sacrificing his safety, for the simple reason that a single-stroke bell is not reliable, inasmuch as yon can get enough leakage, that when you give one signal the cnrrent will hold the armature of the bell up and won't release it again; a man goes to give a second signal and it won't work. I have had several years' experience with them and I still find them absolutely unreliable if yon happen to get any leakag-e at all. I would like Mr. Gould to tell us, when he is running bells off accumulators, whether he has reversed his current at all, that is, changed his positive and negative wires. Occasionally I find that a very great help indeed. The positive wire drives out and the negative absorbs the moisture; and if you are continually reversing you keep yonr leads dry.