em keep above water
without a cork float, which must be tied to the neck of the case; but
the rockets will not dive so well with as without floats.

Cases for these are made in the same manner and proportion as
sky-rockets, only a little thicker of paper. When you fill those which
are driven solid, put in first one ladleful of slow fire, then two of
the proper charge, and on that one or two ladles of sinking charge,
then the proper charge, then the sinking charge again, and so on, till
you have filled the case within three diameters; then drive on the
composition one ladleful of clay; through which make a small hole to
the charge; then fill the case, within half a diameter, with
corn-powder, on which turn down two or three rounds of the case in the
inside; then pinch and tie the end very tight; having filled the
rockets, (according to the above directions,) dip their ends in melted
resin or sealing-wax, or else secure them well with grease. When you
fire those rockets, throw in six or eight at a time; but, if you would
have them all sink, or swim, at the same time, you must fill them with
an equal quantity of composition, and fire them together.

_Pipes of Communication for Water._

They may be used under water, but must be a little thicker in the
paper than those for land. Having rolled a sufficient number of pipes,
and kept them till dry, wash them over with drying oil, and set them
to dry; but when you oil them, leave about an inch and a half at each
end dry, for joints; as, if they were oiled all over, when you come to
join them, the paste will not stick where the paper is greasy: after
the leaders are joined, and the paste dry, oil the joints. These pipes
will lie many hours under water, without receiving any damage.

_Horizontal Water-Wheels._

To make horizontal wheels for the water, first get a large wooden bowl
without a handle; then have an eight-sided wheel, made of a flat board
18 inches diameter, so that the length of each side may nearly be
seven inches: in all the sides cut a groove for the cases to lie in.
This wheel being made, nail it on the top of the bowl; then take four
eight-ounce cases, filled with a proper charge, each about six inches
in length. Now, to clothe the wheel with these cases, get some
whitish-brown paper, and cut it into slips; being pasted all over on
one side, take one of the cases, and roll one of the slips of paper
about an inch and a half on its end, so that there will