THE HYDRO-INCUBATOR.

Most, if not all, of your readers have heard of the newly-invented
machine for hatching and rearing in chickens, without the maternal aid
of the hen; probably many of them have paid a visit (and a _shilling_)
at No. 4. Leicester Square, where the incubator is to be seen in full
operation. The following extract will, therefore, be acceptable, as it
tends to show the truth of the inspired writer's words, "There is no new
thing under the sun:"--

"Therefore ... it were well we made our remarks in some
creatures, that might be continually in our power, to observe in
them the course of nature, every day and hour. Sir _John
Heydon_, the Lieutenant of his Majesties Ordnance (that generous
and knowing gentleman and consummate souldier, both in theory
and practice) was the first that instructed me how to do this,
by means of a furnace, so made as to imitate the warmth of a
sitting hen. In which you may lay several eggs to hatch and by
breaking them at several ages, you may distinctly observe every
hourly mutation in them, if you please. The first will be, that
on one side you shall find a great resplendent clearness in the
white. After a while, a little spot of red matter, like blood
will appear in the midst of that clearness, fast'ned to the
yolk, which will have a motion of opening and shutting, so as
sometimes you will see it, and straight again it will vanish
from your sight, and indeed, at first it is so little that you
cannot see it, but by the motion of it; for at every pulse, as
it opens you may see it, and immediately again it shuts, in such
sort as it is not to be discerned. From this red speck, after a
while, there will stream out a number of little (almost