But in reference to the point in question, that cold accelerates the spawning process, let us take for a moment the general basin of the Oykel waters into view. We know that for several seasons back, the earliest spawning in that quarter has occurred in the Carron, in September. Now, it is certain, that during that month the Carron waters are warmer than those of the Shin. So also the Oykel (properly so called) is itself two degrees warmer in October than the Shin, and yet the latter is the later of the two. It thus appears that warmth may be advantageous both as inducing early spawning in autumn, and an early entrance of fresh-run fish in winter; although a single river may not possess both attributes for the reason hinted at--the deepest waters, though protected from winter's cold, being also screened from summer's heat. Mr Scrope may therefore be regarded as right in his facts as to the earlier season of the upland streams, although his theoretical explanation of them is not conclusive. The lateness of the spawning season in the Shin may, in some measure, be owing to the early breeding fish going up into the loch, from whence, after a time, they fall back upon the spawning places in the fords of the river. The same thing happens in the lower regions of the Tay--the fish fall back from the loch, and the ford between Taymouth Castle and Kenmore is by far the latest in that river. Salmon have been seen to spawn there in February. In regard to the general influence of the atmosphere, we may here remark that frosty weather is good for spawning; because the fish go then into the deeper or central portions of the fords, by which procedure the spawning beds are never dry,--whereas, in time of spates, salmon are apt to deposit their spawn along the margins, and thus the roe is frequently destroyed by the subsiding of the waters.