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]

The Grand Junction Canal is largely utilised by barges traversing the W. of Hertfordshire.  It is conspicuous at Rickmansworth, Boxmoor, and Berkhampstead; it enters Bedfordshire near Marsworth Reservoir.

The New River was constructed by Sir Hugh Myddelton, a London goldsmith, in 1609-13, and is largely fed by springs at Chadwell near Hertford.  Its course in Hertfordshire is mostly close to and parallel with that of the Lea.  The New River caused the financial ruin of its projector; one of its shares is now worth a large fortune.  The whole story of this undertaking is very interesting; but as the New River was cut in order to bring water to London that story belongs to a volume on Middlesex.