RESULTS OF SALMON MARKING 61 
and the growth of the fish with its many surprises, 
must be viewed in strict relation to this divided or 
dual habit of marine sojourn. It would be out of 
place to compare at a given time a fish which had 
returned to fresh water after a short sojourn in the 
sea with a fish which had been feeding and growing 
for twelve or eighteen months. When a classification 
according to short and long periods is adopted, there 
is still much that is difficult to understand and great 
variation in results, but the life of the salmon seems 
to be cleared of that obscurity which has for so long 
defied the penetration of many and varied search- 
lights. Moreover, it is also necessary to give atten- 
tion to the localities from which fish come, since what 
is considered a large fish in one place may be a com- 
paratively small one in another, so that fish of similar 
weight are not necessarily of similar class or age. 
Further, it seems necessary to have regard to the 
particular years in which records are acquired, and to 
compare different periods, when treating the subject 
broadly. Classification by weight, length, or other 
particular is only useful in questions of migration 
when fish of one locality are being dealt with. I was 
never so much impressed with the necessity for com- 
paring only similar periods till a combined analysis 
of Scottish and Irish results was attempted. It has 
been my intention in writing these chapters to avoid 
tables of statistics, because of their rather formidable 
and uninteresting appearance, but in the present 
instance I must ask the indulgence of the reader in 
giving the data—in as condensed a form as possible 
—from which deductions are made. 
