them principally after heavy rains have increased the flow of water out of the pond?  If he answers these questions in the affirmative, I shall still think I am right, and request him to keep a sharp look-out after rains in May and June, when I think he would probably see the grigs passing through his box into the pond.  If, on the other hand, there is no escape of water from the pond at any time, I must admit that I am wrong, but at present I don’t know how to reconcile the impounding the water so completely with what he says about the flow of the water through the box at the bottom of the sill.  Where does the water flow to, and for what is this sill?

G.  H. replied as follows.

T. G. asks if I have caught Eels of the size of a crow’s quill.  I have caught them of the size of a tobacco-pipe, and from three to four inches in length.

Our surplus water flows indirectly into the river Nene from our sluice.  It supplies some stews where we have been in the habit of keeping reserve fish, and passing over several waterfalls, it enters into a ditch which is about three-quarters of a mile long, and then reaches the river I have just named.

The greatest take of Eels I have had was on the 23rd of December, but the time of the year is of little consequence with us, provided the water is thick and muddy and the weather rather warm, which, of course, only occurs during very heavy rains.  If I were to draw all the water out of the pond when in a clear state, I should not catch a fish.  The variety is the Silver Eel.  Our pond is upwards of fifty miles from the sea; therefore how is it that those little Eels had got no larger during their long journey, interrupted as it is by numerous and almost insurmountable obstacles, before they could reach the little ditch, three-quarters of a mile long, that would conduct them to our pond?  And, last of all, after this long and tedious journey, within a hundred yards of their destination they would have to climb four waterfalls and a perpendicular sluice-board.  It appears to me they should have grown much larger than a common tobacco-pipe and longer than three or four inches in that time, but I will leave this point for T. G. to explain.—­G.  H., Finedon Hall.

Reply to the foregoing.

Many thanks to G. H. for his second letter on this subject.  It appears to me that we think very much alike about Eels.

He says his pond is fifty miles from the sea; “therefore, how is it that these little Eels get no larger in their long and tedious journey? interrupted as it is by numerous and almost insurmountable obstacles, before they could reach the little ditch, three-quarters of a mile long, which would conduct them to our pond? and last of all, after this long and tedious journey, within a hundred yards of their destination, they would have to climb four waterfalls and a perpendicular sluice-board.  It appears to me they should have grown much larger than a common tobacco-pipe during that time; but I will leave that point to T. G. to explain.”