Morning journal and courier. [volume] (New Haven [Conn.]) 1848-1894, 1889-07-12

chilled rims; the cylinders arc two and three
sixteenth-inoh bore by three-inoh stroke.
The boiler is made of three.sixteeth wrought
iron, ,and carries forty pounds working press
set to blow off at forty-6ve. The pump,
which is under the engine, between the
links, is worked by an eccentric on the for
ward axle, and fs nine-sixteenth bore by ene-
inch stroke.
A steam pipe heats the water before 1t
reaches the pump. The engine is fitted with
steam brakes, which are placed between the
middle and back driving wheels. There is
also cylinder under the cab which draws
up the brakes on both trucks of the tender.
The brakes on the engine and tender operate
at the same time. Under the working press
ure the brake can be put on with enough
power to skid the wheels on the engine and
tender. The bell rings by steam and is neat
ly finished. The frame of the engine rests
izing bars from the 'front.' trucks to the back
drivers, thus allowing the model to run on
very rough rails without danger of springing
the frame. The driving wheels, when
raised from the track, have made / 1,O80 revo-
lutions per minute under pressure of forty
oil as fuel.
The boy has worked steadily for seven
| months, and the result proves how closely
he has watched the models from which he
has worked. George says now that his
great desire is to get into some locomotive
shop, where he can put to use the knowledge
he possesses.
CONCERNING COBwEBs.
How the Garden spider Employs Hts
Wonderful spinneret.
THE Swiss Cross.1
Let US see how the garden spider uses its
inherited talent. Each individual is en-
dowed with a spinneret or natural spinning
machine, through which can be drawn in
Vulnerable strands so fue that they can be
eeen only under a powerful microscope
(Leeuwenhoeck claims that it takes 4, 4,00O, 900
of these strands to make thread as thick
as o hair from mans head. First, our
spider begins to draw from out her spinneret
| a cord of as many of these strands as seem to
| her good and fastens it to some leaf or twig
| then runs on another leaf, spinning all the
while, fastens again to that, and to another
| and another, continuing until circle is
formed inclosing as large space es she de-
| signs for the outer boundary of her web.
Then she passes back and forth over her
work, adding fresh threads and strengthen
| ing this outer line, which she secures to every
possible object
Finally she stops, fastens her thread with
| special care, and begins to run around the
circle, spinning as she goes; but now carry
ing her fresh thread carefully raised upon
one hind foot, thus keeping 1t from touching
the older strands and becoming glued to
them. When half way round she stops,
pulls her thread tight, fastens it very strong
", and a firm line is drawn straight across
the center of the circle. She runs down this
1 60 &ha y,{IIJo
thread to It there, carries It to new point
upon the outer edge, fastens 1t, and We now
| see that she is engaged in making these lines
in the web that look 80 like the spokss of Q
wheel. She repeats this operation again and
again, until all the radn or spokes are
formed. When they are done she carefully
tests each thread by pulling, to make sure
that it is firm and strong; and, II one proves
unsatisfactory, shs either strengthens or re-
makes it altogether.
Now that the main lines are built, oul
spider goes once more to the eenter point
| and begins to spin again-this time in circles
fastening to each radius as che passes. A
| first these circles, or more correctly spirals
are placed quite close together, but sh'
leaves ever wider and wider space between
, | as she approaches the outer edge. The cute
+ circle and the radii were spun of a silk whicl
becomes dry directly after leaving the spi
der's body, is of great strength and YER
= firm; but these spirals are formed of q sub
} stance which differs essentially. When frs
} drawn from the spinneret it is extremel
: gIutinous-s most important property, as b
? this it is enabled 80 adhere tenaciously to th
9 radii-and it is, besides, SO highly elastic 6
{ to be capable of being pulled far out o
} place without breaking. When the spiral
are finished the spider returns again to th
J center and c-ocsedes 70 bite cE the point 6
| all the radii close to the first enciroling line
. | by which she much increases the elactioit
, Iof her web. II is In or beneath this oen
7 tral opening that the spider usually sits an
! | watches for the coming of her prey.