Tur Emperor LEADS IN Person. 407 
CHAPTER VIL 
SALMON-PASSES, LADDERS, ETC. 
g\.4VING studied ancient aquaculture 
and fish-culture, and examined the 
modus operandi for water-farming, 
with its profits a thousand-fold 
greater than those from cultivating 
the soil, the reader will have ar- 
rived at the threshold of an im- 
provement as necessary as are all 
the previously-named operations. 
One of the most important ques- 
tions of the day in reference to the 
fresh-water fisheries of the United 
States—especially to those devoted 
to the propagation of salmon and 
trout—is how to expand and devel- 
op them to the greatest extent, so 
as to interfere as little as possible 
with existing arrangements as to 
mills and proprietary rights. That 
the salmon should breed, it is ab- 
solutely indispensable that it should be able to reach the 
heights and shallow portions of rivers, which alone afford 
suitable gravel-beds for the operation of depositing the ova 
and rearing the young. If it can not get to these, the breed 
of salmon is soon extinguished, and this has been the cause 
of its extinction in ninety-nine rivers out of every hundred. 
Mill-dams, those terrible enemies to the salmon, are the prin- 
cipal offenders in this respect. Commercial and manufactur- 
ing interests being almost too strong for the salmon, the 
