The practical
limits to the ringing of the gong are that it will stop sounding after
the head of the train has passed the crossing and before or very soon
after the rear has passed. A "wild" engine running very slowly might not
actuate the signal as long as was desirable, but even then it is not
unreasonably claimed the warning would probably last long enough for all
practical requirements, as a team approaching a crossing at eight miles
per hour takes 42 seconds to go 500 feet. All the bearings of any
importance are self-lubricated by oil cups, the whole apparatus being
designed to require inspection not more than once a month. The iron case
when shut is water-tight, and when duly locked cannot be maliciously
tampered with without breaking open the case; so that, the manufacturers
claim, it will not be essential to examine it more than once a month.
The parts outside the case are all strong and heavy, and not likely to
get out of order, while easily inspected.
The apparatus can be used for announcing trains as well as sounding
alarms, as the gongs can be placed upon any post or building. The gong
has a heavy striker, and makes a great deal of noise, so that no one
should fail to hear it.--_Railway Review_.
* * * * *
THE SIZES OF BLOOD CORPUSCLES.
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