THE YOUNG SCIENTIST. 
267 
Stream of water against the printed side. 
Itt a few moments the chemical that lias 
been covered by the black lines of the 
drawing will be washed away, leaving 
the white paper exposed, which will 
represent the lines of the drawing; the 
surface of the paper which has been ex- 
posed, will retain the chemical, and in 
various shades of blue, according to the 
amoimt of time it has been exposed to 
the light. It is now only necessary to 
hang the print up, and allow it to dry to 
be ready for use. 
Something About Saws— VII. 
BY "our NED." 
N the July number of the Young 
Scientist I described and gave 
several illustrations of clamps 
and other devices for holding 
and sharpening saws. Perhaps I ought 
to have shown and described the "saw 
sets" shown in the present article, for 
the setting of a saw must be done before 
the filing takes place, otherwise the teeth 
will have their fine cutting edges broken 
away. Every amateur who uses a saw 
should make a note of the above hint, 
and in no case set a saw after it has been 
newly filed. 
Sometimes, if a saw is very much out 
of order, it is roughly filed, so as to give 
the teeth the right form, pitch and size, 
before setting ; but when such is the case, 
the saw, after it has been set, is again 
filed, and the teeth brought up to proper 
working order. 
When a saw is in very bad shape, similar 
to the illustration shown at Fig. a, in the 
February number of this journal, it can- 
not be "set" accurately until the teeth 
are made the right shape and size ; and 
this can only be done by first jointing the 
edge of the saw with a fine flat file, cut- 
ting down the points of the teeth until 
the jointing file touches every one of 
them, and the line of teeth, from handle 
to point, is straight and regular. When 
this is done to the satisfaction of the 
operator, then the rough filing may take 
place, and proper form, size and pitch 
given to the teeth, after which the setting 
process may be performed, followed by 
filing the teeth to working order. 
There are a great number of " saw- 
sets" in the market, each claiming for 
itself special merit, but I am of the opin- 
ion that there is no tool offered for sale, 
that will set a hand-saw as good as the 
old-style hammer set, when in the hands 
of an expert setter. 
Fig. 1. 
Fig. 1 shows the kind of hammer, a, the 
sawmaker generally employs when set- 
ting hand-saws. The saw being laid 
nearly flat, with its teeth along the ridge 
of a rounded-edged anvil or stake, b b, 
held in the tail vise ; the angle is in great 
measure determined by the curve of the 
stake, which is, for fine-toothed saws, 
considerably pointed. Half tlie teeth 
having been bent, the saw is turned end 
for end, and the intermediate teeth simi- 
larly treated. 
The sets c d are commonly employed by 
the users of saws, requiring less skill to 
give the proper inclination to the teeth — 
c is used for large, and d for small saws. 
They consist of narrow blades of steel, 
with notches of various widths, to accom- 
modate different tliicknesses of blades. 
The saw is held between clamps, the 
alternate teeth inserted a little way into 
the notch 
which they 
most nearly 
fit, and bent 
over to the 
proper angle 
by pressing the 
handle of the 
tool; the oper- 
ation is then repeated on the intermediate 
teeth. 
Sometimes saw-set pliers, e, Fig. 2, are 
used. These require two adjustments: 
Fig. 2. 
