the
train the longer the bell will ring, a very convenient property, since
the slowest trains have nearly always the most wheels. 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.

Professor Theodore G. Wormley, in the new edition of his work, gives the
following sizes of blood corpuscles, as measured by himself and
Professor Gulliver. We have only copied the sizes for mammals and birds.
It will be seen that, with three or four exceptions, the sizes obtained
by the two observers are practically the same:

Mammals Wormley. Gulliver.

Man 1-3250 1-3260
Monkey 1-3382 1-3412
Opossum 1-3145 1-3557
Guinea pig 1-3223 1-3538
Kangaroo 1-3410 1-3440
Muskrat 1-3282 1-3550
Dog 1-3561 1-3532
Rabbit 1-3653 1-3607
Rat 1-3652 1-3754
Mouse 1-3743 1-3814
Pig 1-4268 1-4230
Ox 1-4219 1-4267
Horse 1-4243 1-4600
Cat