THE YOUNG SCIENTIST. 
13 
into their proper shape. The fastenings 
at the intersections are pieces of the 
metal bent around and pinched tight by 
the pliers. A strip of the metal should 
be bent around and fastened to the entire 
pattern for the purpose of attaching it to 
the stiles and rails of the panel or franie. 
At the intersection of the centres of each 
main section of the design, where the 
summer fire-place screen, and wrought of 
brass, lacquered, has a very rich appear- 
ance. Narrow hoop iron, strips of galvan- 
ized iron, 2inc, heavy tin, or other mate- 
rials might be used, each kind being: 
suitable for some particular purpose. 
When hoop iron is used it should be either 
bronzed or japaned. 
A Mathematical Puzzle and a Lesson in 
Geometry. 
UK very young readers who wish 
to exercise their mathematical 
abilities may cut out four pieces 
of cardboard, the exact size and 
shape of the figures given below, and try 
to put them together so as to form a per- 
fect square. There are several methods 
of transferring the figures to cardboard 
so as to get the pieces the exact size and 
shape required. One is to lay the card- 
board under the page, and stick a pin 
through the three corners or angles. The 
pin marks must now be joined by lines 
drawn with a ruler, and the figures will be 
complete. Another way is to draw the 
figures on transparent paper laid over the 
page, and then gum the thin paper firmly 
c 
a h 
MECHANICAL PUZZLE. 
metal is twisted to show its flat surface to 
the face, rivets are used to hold the parts 
together. 
This kind of work may be applied to a 
thousand different purposes. It looks 
particularly well when used in making a 
to the card, after which card and paper 
may be cut up as required. But the most 
elegant method is to draw the figures 
geometrically. Take the left hand figure 
to begin with and draw a straight hori- 
zontal line. Then with a pair of com- 
