is done here and elsewhere from July to the end of November, when
the Eels are on their downward migration. Will G. H. be kind
enough to say whether he does not catch his about the same time?
will he also say whether the Eels he catches are not Silver Eels?
and will he also state whether he does not catch 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,