John Hanning Speke questions about the height and extent of the lake could not be answered easily. Speke's eyes were still bothering him and he only saw a small part of the southern end of the lake and his view was blocked by islands in the lake so he could not judge the size of the lake well. However, Speke did estimate the elevation of Lake Victoria at 4000 feet by observing the temperature at which water boiled at that level. (This lake's being substantially higher than Lake Tanganyika did make it a more likely candidate for the source of the Nile.) From
John Speke (1442-1518) John Speke (1442-1518) Sir John Speke (1442–1518) of Whitelackington, Somerset and of Heywood in the parish of Wembworthy and of Bramford Speke both in Devon, was Sheriff of Devon in 1517 and a Member of Parliament (1477). He was knighted in 1501. His monument is the "Speke Chantry" in Exeter Cathedral in which survives his recumbent effigy. He was born in about 1442, the son and heir of Sir John Speke (died 1444) (buried at Bramford Speke) of Wembworthy and Bramford Speke, Devon, by his wife Alice Beauchamp (died 1445/46) (who survived him and remarried to Henry Hull) daughter and