d powder in the con- ing currents, it is indispensable to take precautions is spoken of. A current is rated by amperes, not by dition of sharp dust, and intensely heated—rush against the phenomena of induction. It might seem through the insignificant crannies between the shot as if the most… … few discharges. Soft tough metals resist abrasion ex- ceedingly well. Thus, for instance, it is very difficult SECTION OF A PARIS SEWER, to cut copper on a fine emery wheel. Lead cannot be so cut at all. The end of a copper bolt may be held Now, such cables, which are already employed in seve-…
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