THE YOUNG SCIENTIST. 
49 
was made larger by sawing close to the 
lines. A little difficulty was met witli 
Fig. 29. 
when the saw had travelled to the corners ; 
it was found that the saw would not turn 
at right angles and leave a nice square 
corner. This trouble was got over by first 
sawing " square up into the corner," and 
then taking the saw back about an inch 
from the angle and starting it in the wood 
again, and making a short curve with it 
until it struck the line. The sawing was 
continued in this direction until the next 
angle was reached, when the saw was 
taken out and turned with its teeth in a 
contrary direction, and the little curve in 
the corner just passed was cut away. All 
the other corners were treated in a similar 
manner. 
The house proper was finished, so far as 
the boys were concerned, but, as they had 
promised to make furniture for it, they 
had still plenty of work on hand, and 
Jessie was quite anxious, now that the 
house was built, to get it furnished and 
completed ; so it was decided to go right 
to work at the furniture. 
Let us see how they get along ! 
(To he continued.) 
The Water Telescope. 
THIS efficacious and cheaply-made in- 
strument is not used so much in this 
country as its merits deserve. The Nor- 
wegian fishermen are constantly in the 
habit of employing it in their herring and 
cod fisheries, and often thereby discover 
shoals of fish that would otherwise escape 
their nets. On the surface of the water in 
the sea, and also in most rivers, there is 
generally a ripple, which prevents the 
bottom being seen ; it is to get rid of this 
ripple that the water-glass is so useful. 
There are two forms of water glass — 
namely, an ordinary bucket or barrel, 
Fig. 29 shows a keyhole or pad saw. The blade 
is quite thin, and not more than H of an inch 
wide at the point. It is fixed in the handle by 
two set screws, which are adjusted by a screw- 
driver. A narrow slot runs through the handle, 
in which the saw maybe lengthened or shortened. 
with the bottom knocked out ; second, a 
piece of tin of a funnel shape, about three 
feet long and nine inches diameter at 
the broad (or bottom) end, and large 
enough at the top to accommodate the 
observer's eye — into the broad end should 
be inserted a plate of strong glass, and 
some lead to weigh it down. When the 
water is clear this instrument will enable 
the observer to see from three to twenty 
fathoms on calm bright days. Of course 
when the water is muddy or discolored 
the glass is useless. The Cornishmen, 
especially at the Landsend, use these in- 
struments for looking for wrecks, lost 
crab and lobster pots, etc. To tlie na- 
turalist they will be invaluable, as by 
means of them the actions of the fishes 
and other inhabitants of the ocean can be 
observed better than in any aquarium. 
The beauties and luxurious growth of the 
submarine forests of sea plants will also 
to many be a most novel and interesting- 
spectacle. To water parties who picnic 
on rivers or near lakes, the water tele- 
scope will be found a great addition to the 
day's enjoyment, as by means of it sub- 
aqueous scenery may, possibly for the 
first time, be brought into view, and 
many a panorama opened up to the human 
eye quite as beautiful, if not more so, than 
many a view in distant countries where 
friends and relations are enjoying an ex- 
pensive tour. 
Smoke Rings. 
IN a former number of the Young Sci- 
entist we described a very simple de- 
vice for showing the curious "smoke 
rings " which are produced when air, 
loaded with visible smoke or vapor, is 
expelled in puffs from any reservoir. The 
engraving shows a larger and more effec- 
tive device for the same puri)ose. A cheap 
box (a small tea chest answers very well) 
has a hole bored in one end, and over the 
other is tacked a piece of stiff paper. 
Through two small holes in the side are 
inserted the nozzles of two small tube re- 
torts, one containing hydrochloric acid, 
and the other strong liquid ammonia. 
The retorts are heated by two small 
lamps, and the vapors that are given off 
