28 FISH CULTURAL ASSOCIATION. 
then leaving a good margin for safety, of course aerate the water 
so often and no oftener. You then insure the lives of your fish 
and spare yourself unnecessary labor. 
(8.) Changing water during the journey is a dangerous thing 
and is the snare that the beginner most easily and most often 
falls into. Except when travelling with young shad or other fish 
that require change of water for the food it contains, there is 
very little need of changing the water much during the journey, 
and as a general rule there is danger in doing so. The more 
any one travels with live fish the less he changes the water on 
them. This lesson was impressed upon me in my very earliest 
experience in fish-culture fourteen years ago, in attempting to 
bring live trout from Monadnock Lake to Charlestown, N. H. 
The original lake-water which I took them in would have carried 
them a week, but I changed it three times in going the first ten 
miles. The fourth time I changed it the water proved to be bad 
and killed every one of the trout within twelve miles of our 
starting point. I have no doubt most fish-culturists could relate 
a similar experience. At all events, I can say for myself, that 
now I change the water less and less every time I travel with 
fish. This course commends itself to reason. In changing the 
water the risk becomes cumulative. Suppose that there is but 
one chance in fifty of getting injurious water at such change. 
In changing twenty-five times there are twenty-five chances out 
of fifty, or an even chance of killing your fish. On the other 
hand you are sure the water you start with is good, and as long 
as you keep it so it will not hurt the fish. Now ina journey of 
almost any length, when you use ice, the melting of the ice to- 
gether with the dripping of the water for aeration, is usually 
quite sufficient to keep the water in good condition. Ice is almost 
always safe to use for two reasons: ice-cutters do not get their 
ice from impure water, and then besides, the freezing of the 
water generally frees it from such impurities as there may be in 
it. But it is not the ice alone that keeps the water good, but the 
friction of the constant dripping of it back and forth freshens 
and purifies it like a running brook. Indeed, if you dip the 
water continuously in the fish-tank it becomes practically a run- 
