American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 32
ensitypoint. But, again, these measurements require the attendants time, and would not,on that account, work altogether satisfactorily on a large scale. For general pur-poses, as already said, the appearance of a battery will indicate to an intelligent at-tendant the time for renewal. The tendency… … BATTERY SYRINGE. The hydrometer commonly used for the foregoing purpose, consists of a glassbulb, about an inch in diameter, to which is attached a narrow glass stem, 5 or 6inches in length. A quantity of small sliot is inserted in the bulb—sufficient to sinkit to a desired depth in pure water. A…
Telegraph
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