62 
THE YOUNG SCIENTIST. 
is made larger, so that the main rope 
may go round it twice, and the two ends 
of this rope pass througli a sleeve of light 
leather or heavy duck, so as to prevent 
entanglement. One end of the main rope 
has a loop through which passes a stout 
leather belt, long enough to go round the 
waist of any person ; the other end is free. 
When in use, the upper rope is fastened 
securely to the building, or to any heavy 
object that cannot be dragged through 
a window ; the belt is then fastened round 
the waist, and the person who is to de- 
scend draws the other end of the rope 
A SIMPLE FIEE ESCAPE. 
tight, and holding it firmly in the hand, 
steps off the window sill. By easing the 
end of the rope that is held in the hand, 
we may lower ourselves as rapidly as may 
be desired, while at the same time a strain 
of a few ounces will create enough fric- 
tion to support the heaviest individual. 
Such a fire escape may first be used by 
the men to lower all women and children, 
and afterwards the men may descend one 
by one. It is so cheap and simple that 
any person can procure one, and it can 
never fail or get out of order. 
Practical Hints on the Construction of 
the Violin-IL 
T ET us now suppose the materials from 
-Li which we are to construct our violin 
to have undergone the necessary season- 
ing and drying process. The next thing 
to be done is to provide ourselves with 
tools. The amateur violin-maker will 
find this one of the most discouraging 
obstacles to be overcome. He will search 
hardware stores and tool-makers' shops 
in vain, and in the end will find himself 
under the necessity of making most of the 
implements he needs. We will endeavor, 
as we go along, to give an idea of the 
requisite tools, but in the absence of 
proper drawings, the description must 
necessarily be very incomplete. 
I We shall commence with the back or 
under table of the instrument. Two of 
the wedge-shaped pieces of maple are 
dressed down neatly with the plane, and 
then clamped firmly in the vice with their 
thick edges together as they grew. The 
thick edges are then planed down and 
neatly jointed. For this purpose the 
plane must be very sharp and accurate, 
or else it will be found impossible to make 
a good joint. When the joint is absolutely 
perfect, the pieces are slightly warmed, 
one of them is clamped in the vice, the 
surfaces to be joined covered with good, 
rather thin and hot glue, and rubbed one 
on the other until the glue begins to set. 
If the pieces rock or swim during the 
rubbing, it is an evidence of bad jointing, i 
and they must be separated, the glue 
cleaned off with a little warm water, and ; 
a new joint made. If the joint be good 
the parts are allowed to remain in the 
vice until well set, and then put away in a 
dry place for at least twenty-four hours. 
In no case should they be clamped to- 
gether, as a joint thus made is always 
liable to open and leave an unseemly ! 
line dow^n the centre of the back. The I 
two pieces which compose the belly of the 
instrument must be treated in the same 
manner as those for the back, but being 
