le 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
passing W. of Great Wymondley runs to Purwell Mill, and joins the Hiz at
Grove Mill.

12. _The Quin_ rises in the neighbourhood of Wyddial, and passing
Quinbury, unites with the Rib at Braughing.

13. _The Rhee_, rising a little E. of Ashwell, has but a few miles to
flow before it enters Cambridgeshire.

14. _The Rib_ rises at Corney Bury, flows E. of Buntingford, thence
turning W. it flows under the bridge at the _Adam and Eve_, runs to
Westmill, Standon and Thundridge, finally uniting with the Lea at
Hertford.

15. _The Stort_ enters Hertfordshire from Essex at a point near Cannon
Wood Mill, and after passing through Bishop's Stortford forms the
extreme E. boundary of the county for some distance before quitting it
near Cheshunt.

16. _The Ver_ rises near Flamstead, is crossed by the Dunstable Road,
N.W. of Redbourn, then recrossed by it. It then skirts St. Albans on the
S. and joins the Colne near Park Street.

In addition to the cutting of the _Lea and Stort Navigation_ already
mentioned, there are other artificial waterways:--

_The Aylesbury Canal_ (a branch of the Grand Junction Canal) crosses the
extreme western neck of the county, from S. of Puttenham to S. of
Gubblecote.

[Illustration: GRAND JUNCTION CANAL AT TRING
_The highest water level in England_]