When the LEASES were granted in 1808 to KENNYS and others the lease was always constructed as follows :

 

 INDENTURE BETWEEN THE RIGHT HON. WILLIAM WENTWORTH EARL OF FITZWILLIAM AND RIGHT HON. CHARLES WILLIAM WENTWORTH FITZWILLIAM COMMONLY CALLED VISCOUNT MILTON THE SON AND HEIR OF THE SAID EARL OF THE FIRST PART AND ...................................WHEREBY THE SAID EARL AND VISCOUNT MILTON APPOINTS DEMISES AND GRANTS UNTO SAID ............. ALL THAT DWELLING HOUSE TENEMENTS AND ALSO ALL THOSE SEVERAL CLOSES ENCLOSURES OR PARCELS OF ENCLOSED LAND ARABLE MEADOW AND PASTURE GROUND THERETO BELONGING PART OF THE LANDS OF ......................... CONTAINING WITH THE SOIL UNDERNEATH THE BUILDINGS ACCORDING TO A SURVEYED ADMEASUREMENTS THEREOF LATELY MADE BY MR. CALEB BROOKSBAND...........................( BE THE SAME MORE OR LESS) WHICH SAID PREMISES WERE ( AMONGST OTHER TENEMENTS) LATE IN LEASE TO................. AND SINCE TO ........................ AND ARE NOW IN THE POSSESSION TENURE HOLDING OR OCCUPATION OF SAID ................... TOGETHER ETC . TO HOLD FROM .................... FOR AND DURING THE NATURAL LIFE OF ..................... FOR 21 YEARS TO RUN THEREWITH AT AND UNDER THE NON-RESIDENCE RENT OR SUM OF #................... and #...........TO PLANT ........ FOREST AND ............... APPLE TREES. LIBERTY TO COPPICE .................

 Many of these lease refer to the life of one of the children.  The tenants would usually list one of their children as  "In life of Hannah Kenny" for protection that their lease could last longer for them. If I am not mistaken, it would actually run 21 years after the said persons life. 

If you add the following names and conditions to this LEASE then you get what all those at KILCAVAN received as proof of lease; For an example of what goes into the blank areas......

WILLIAM KENNY 29th August 1808

Part of KILCAVAN

13 acres 1 rod 39 perch

late in lease to Nicholas Kempston and William Hume both deceased.

In the LIFE of HANNAH KENNY 4th daughter of WILLIAM KENNY then aged 10 years old.

#15 residence and #10 to plant 100 forest trees and 20 apple trees.

Liberty to coppice one acre.