5. _The Colne_ rises near Sleap's Hyde, is crossed by the main road from
Barnet to St. Albans at London Colney, and by the main road from Edgware
to St. Albans at Colney Street. Thence it passes between Bushey Hall and
Bushey Lodge, flows through Watford to Rickmansworth where, uniting with
the Gade and Chess, it enters Middlesex near Stocker's Farm.

6. _The Gade_ rises near Little Gaddesden, skirts Hemel Hempstead Church
on the W. side, and passing King's Langley and Hunton Bridge, flows
through Cassiobury Park and joins the Chess and Colne at Rickmansworth.

7. _The Hiz_, rising at Well Head, S.W. of Hitchin, crosses that town,
joins the Purwell at Grove Mill and leaves the county at Cadwell.

8. _The Ivel_ rises near Baldock, flows to Radwell Mill and shortly
afterwards enters Bedfordshire.

9. _The Lea_ is the largest river in Hertfordshire. It rises near
Leagrave (in Bedfordshire) and flows through the county from N.W. to
S.E. Entering Hertfordshire at Hide Mill, it flows past Wheathampstead,
Hatfield, Hertford, Ware, and, leaving the county near Waltham Abbey,
enters the Thames at Blackwall. Its entire length is about 50 miles. The
waterway known as the _Lea and Stort Navigation_ is navigable to
Bishop's Stortford.

10. _The Maran_, or _Mimram_, rises in the parish of King's Walden,
skirts Whitwell on the N., running parallel with the village street, and
passing through Welwyn and near Tewin enters the Lea at Hertingfordbury.

11. _The Purwell_, or _Pirall_, rises in the parish of Ippollits and