THE YOUNG SCIENTIST. 
75 
greatly, and set me to thinking and rea- 
soning out the cause of so strange a phe- 
nomenon. I had read in some book that 
the result of the constant agitation of the 
ocean by means of tides, winds, and waves 
was to keep the water in a i)erfectly fresh 
condition suitable for the healthy exist- 
ence of the animal and vegetable life. I 
then remembered my anxiety regarding 
the safety of my fish during their journey 
on account of ttie constant slashing of the 
water in the can, as the wagon passed 
over the rough cobble stone pavements of 
the streets; and yet the life of my fish 
had been preserved by this very alarming 
jolting and consequent agitation of the 
water. From this experience was sug- 
gested the idea of raising the water 
in the collecting can by means of a 
hand dipper, and allowing it (the water) 
to fall from a height of some two feet 
back into the can, and by this means 
nose to the surface, clearly detect the 
change ; and so I came to learn that salt 
water, no matter how foul it may become, 
can always be restored to a healthy con- 
dition for sustaining animal life by rest- 
ing it in a dark room, then agitating it as 
above described, and carefully pouring it 
back into the aquarium after it has rested 
for a day or so. And thus you see how 
knowledge was gained by the accidental 
missing of the steamboat and my ride 
over the rough streets of B . For 
a small collecting can I know nothing 
better than the one shown in Figs. 1 and 2. 
Fig. 1 is an ordinary milking can well 
coated both inside and outside with asphalt 
varnish ; a hole is cut into the side which is 
strengthened on the inside and outside 
with a heavy tin collar, as shown at a, 
into this hole a cork is inserted. Fig. 2 
is a can one-half inch smaller in circum- 
ference than that shown in Fig. 1, into 
> Fig. 3.— ZINC CAN AND PUMP. 
driving vast quantities of minute globules 
of air into the water and thereby oxygen- 
ating it thoroughly. I had often saved the 
salt water contained in my tanks, which 
had become charged with carbonic acid, 
by pouring the water back and forth into 
a pail till it foamed, thereby releasing 
\.ne poisonous gas and charging the water 
with oxygen till I could, by placing my 
which it is intended to fit. On the sides 
of the can b, eight corks one-quarter of an 
inch in thickness, are fastened, as shown 
at c c c, c c c, and also three on the bottom 
of the can c c c. The sides of the inner can 
B is perforated with small holes as shown 
in Fig. 2 ; at the bottom the perforations 
cease where the corks are attached as 
shown in the cut. This inner can is pro- 
