104 THE LIFE OF THE SALMON 
spring of 1906, and was caught on the date already 
given. 
This Helmsdale fish is typical, and the photo- 
graphs show more plainly than any description can 
do the characteristic appearance of the kelt and 
adult clean fish scales. The magnification is in each 
case 12 diameters. The additions G. and H. on 
the later scale may appear slight in compari- 
son with those seen in the kelt scale, but it is to 
be recollected that as the age of a salmon increases 
the rate of growth decreases. The first two summers 
in the sea invariably show the greatest growth in 
the fish. 
Evidence from scales of fish which have been 
marked and recaptured is evidence of the most 
reliable kind, and several instances might be cited 
similar to the Helmsdale fish marked 1180. On 
account of the nature of the evidence also, I consider 
that there need be no hesitation in deducing evidence 
from scales of fish for which no marking record is 
available, provided always that the observer has a 
competent knowledge of the subject and the scale 
be taken from a suitable part of the fish, ¢.g., the 
“ shoulder.” 
With regard to the number of lines which will be 
found on the scales of fish of different ages, it may 
be said that from marked kelts recaptured as clean 
fish, a scale having been obtained only at time of 
recapture, Mr. Johnston has found that after the 
smolt stage is passed a grilse may add 25 to 28 lines 
the first year; if then it enters the river to spawn 
as a grilse the lines will vary according as it enters in 
