Laxey Wheel Isabella was celebrated by the people of Laxey with a grand fayre on Saturday 24 September 2004. It is currently maintained by Manx National Heritage as part of the Great Laxey Wheel & Mines Trail. The wheel features today on the reverse side of the £20 notes issued by the Isle of Man Government. A water-powered wheel was used because the Isle of Man does not have a supply of coal for a steam-powered pump. Water from the surrounding area – including a number of local springs and streams – is collected in a cistern, which is above the level
Table of the largest known graphs of a given diameter and maximal degree Table of the largest known graphs of a given diameter and maximal degree In graph theory, the degree diameter problem is the problem of finding the largest possible graph for a given maximum degree and diameter. The Moore bound sets limits on this, but for many years mathematicians in the field have been interested in a more precise answer. The table below gives current progress on this problem (excluding the case of degree 2, where the largest graphs are cycles with an odd number of vertices). Below is the table of the vertex numbers for the best-known graphs (as of