THE YOUNG SCIENTIST. 
147 
Note 12th.— Procure any common ordin- 
ary box, fill one end of it, about three- 
fourths up to the top, with cotton, form- 
ing a sloping plane. Make a moderate 
hollow to receive it, and place the bird in 
its right position. If you wish to elevate 
the wings do so, and support them with 
cotton. If you wish to have the tail ex- 
panded, reverse the order of the feathers, 
beginning from the two middle ones, and 
when dry place them in their true order, 
and the tail will preserve for ever the ex- 
pansion you have given it. In three or 
four days the feet lose their natural elas- 
ticity, and the knees begin to stiffen. 
When you observe this, it is the time to 
give the legs any angle you wish, and to 
arrange the toes. When the bird is quite 
dry, pull the thread out of the knees, and 
take away the needle, and all is done. 
Flying Machines. 
TO be able to fly like a bird has always 
been an object of great desire to most 
men, and to-day there are hundreds of 
inventors, old and young, who are wast- 
ing their time and energies on flying 
machines. The visitors to the late fair of 
the American Institue might have seen a 
flying machine for which the inventor 
made the most extravagant claims, and 
yet to any person at all familiar wiMi 
sound mechanical principles it was ob- 
vious that this machine never could be of 
the slightest utility. 
There are two problems involved in the 
flying machine, and inventors are very 
apt to get confused in regard to them. 
First of all we have to provide means for 
supporting the machine in the air ; and 
secondly, it is necessary to have some way 
of propelling the machine without regard 
to the direction of the aerial currents— that 
is to say, of the wind. Before the days of 
balloons, machines had been made to sup- 
port themselves in the air by their own 
motion. The flying pigeon made by 
Archytas was a striking example of this, 
and in more modern times we have many 
instances where heavy bodies are sup-^ 
ported by the resistance presented by the' 
air to their motion. One of the most 
familiar of these is the " artificial pigeon " 
used by sportsmen. This consists of a 
piece of sheet iron formed into the shape 
of the screw of a steam vessel. It is placed 
on a spindle around which a cord is wound, 
and when this cord is rapidly drawn off 
the spindle and screw revolve with great 
speed, just as a humming top revolves 
when the cord is drawn off. The screw then 
rises to a great height in the air, and 
sometimes flies to a distance of sixty to 
one hundred yards. Our young friends 
who wish to try this experiment can easily 
make the apparatus out of a common 
spool and a piece of card. The card is 
cut to the form of a propeller screw and 
twisted in the same way. Two pins are 
driven into the end of the spool about an 
eighth of an inch from the hole and on 
opposite sides, and holes are made in the 
card so that it may be slipped on these 
pins and held fast while the string is being 
drawn off the spool. As soon as the 
string leaves the spool, however, the card 
becomes loose and flies off to a consider- 
able distance. 
Another mode of showing the mechan- 
ical action of the air is as follows : Make 
a wheel with rim and spokes out of card- 
board as shown in the figure. The card 
must be cut away so as to leave but very 
narrow spokes so that the air may have 
plenty of room to pass through. To each 
spoke is pasted a piece of stift' writing 
T^aper cut to the shape of a long triangle. 
The paper is then bent upwards so as to 
present a slanting face to the current. 
When such a wheel is thrown into the 
air and fanned from beneath as shown in 
the figure, it will first be supported by the 
current from the fan, but as soon as this 
has produced a sufficiently rapid rotation 
the wheel will continue to mount of itself 
until it stops spinning. Such a wheel 
might be made to revolve by means of a 
spool fixed as we have just described, and 
then it would rise without any fan. 
And older and more common than all 
these are the wings of birds, which show 
that weights of many pounds may be 
raised and transported through the air by 
mechanical means alone. 
Thus far, however, all attempts to raise 
and propel a weight as great as that of an 
ordinary man by mechanical means have 
