THE YOUNG SCIENTIST. 
77 
the stuff turned, and the same operation 
repeated, with the blade of the try-square 
made to coincide with the work already 
made, there will be no difficulty in under- 
standing the reason why any line may be 
carried round a piece of trued stuff so that 
all the lines wall meet at the corners, and 
yet be at right angles with the edges of 
the stuff. 
Fig. 37. 
This matter being now fully understood, 
Mr. Carpenter instructed the boys how to 
make a table like the one shown in Fig. 
37. The legs and sides were cut out with 
Fig. 38. 
the scroll saw ; two legs and one side in 
one piece formed one side of the table, the 
other side being similar. The ends were 
cut out seperately, and were glued and 
bradded on to the legs, as shown. The 
following are the dimensions of the pieces 
used in making the table : 
Height of legs and sides, 21 inches. 
Length of sides over all, including legs, 
5s inches. 
Fig. 39. 
Length of the end pieces over legs, 2k 
inches. 
Length of table top, 6 inches. 
Width of table top, 3 inches. 
Width of end and side pieces, half-inch. 
The stuff used for the table should not 
Fig. 40. 
be less than half an inch thick, and may 
be of white-wood, pine, or other soft 
wood, and, when finished, should be 
painted in appropriate colors. 
Fig. 3G shows a tenon and mortise. The tenon, t, 
should seldom exceed one-third of the thicliness 
of the stuff, otherwise the piece containing mor- 
tise, M, will be weaker at that part than the tenon. 
After the tenon has been driven home, so that the 
shoulders, s s, bed fairly on the surface of the 
wood around the mortise— in which they will fail 
if all the parts be not exactly square— the hole, 
p p,must be bored, but rather smaller than it will 
ultimately be required. The tenon must then be 
withdrawn from the mortise, and the hole.p, be 
enlarged to the proper size for the pin ; p must 
also be increased to the same size, but its centre 
is removed a trifle towards the shoulders, s s, so 
that when the tenon is reinserted in the mortise, 
the holes, p p, will not exactly tally. The dis- 
crepancy should be very slight, otherwise the 
tenon may be split when the pin is driven home. 
By setting the hole in the tenon a little behind 
that in the mortise, the pin is enabled to draw the 
tenon forM^ard until both tlie holes correspond, 
when the shoulders, s s, will bear firmly on the 
surface, M. 
