If we allowed that they travelled a mile in the hour, and that the obstructions of the waterfalls and sluice-board took as long to get over as all the rest of the journey, they would be able to reach G. H.'s pond in four days from the sea; and from what I have seen of their ability to surmount such obstructions, I am quite convinced that they would travel that distance in the time. But say they were a week--they would not grow much in that time, particularly if they had been travelling without food the whole of the distance, and that they must have done so, is proved to my mind by their keeping in column; for if they had dispersed to seek for food, by what contrivance were they marshalled into line again, to enable them to proceed? Now the place I saw them is forty miles from the sea, although not that distance from salt- water. T. says it is no proof that Eels are bred in fresh water because they may be found in ponds having no connection with a river--the proof required is _ab ovo_. If we wait for this proof I fear we will have to wait for some time, for I fancy that no one but Mr. Boccius ever saw the ova of Eels, and he will not condescend to enlighten us on the subject. At the same time I admit that finding them there is no proof that they were bred there, inasmuch as I have myself stocked such ponds for my friends, and what I have done may be done by others. T. says further there is also room for inquiry into another curious subject--do Eels return to fresh water after having gone to the sea for spawning? In reply to this, I can only say, that no trace of such a migration is ever seen here, and I think if it existed at all, I should have observed it, for the following reasons. The Ribble here supplies a large mill, the water-wheels of which are 150 horse-power; therefore, when they are at work in the daytime, the whole force of the river is often passing through the mill-lead (goit) and the bed of the river between the weir, and the tail goit in such times is left dry, except in a few pools. If there was a shoal of Eels between these two points it would have been seen at one time or another, and this has never happened, so far as I know. It may be said that they migrate singly, but they don't do so in their first migration, and, so far as I am aware, it is not the habit of any animal to do so. Herrings, Pilchards, Smelts, Flounders, Sturgeon, Bisons, Antelopes, Woodcocks, Swallows, Fieldfares, Locusts, and even Butterflies congregate together previous to migration. NOTE.--The last paragraph requires some modification, as I have since proved that Eels migrate singly when going to the sea, as I have had occasion to know in a hundred cases when watching my Eel- trap, where every Eel may be seen as it descends into the trap. _On the same subject._