96 TRANSACTIONS OF THE PLYMOUTH INSTITUTION. 
of Devon and Cornwall, Eisdon conjectures about the days of 
King David, and perhaps some centuries sooner. They are 
supposed to have kept the secret of the position of the 
Cassiterides to themselves for some two or three centuries, until 
the Romans, perfecting themselves in navigation, broke up the 
monopoly — Strabo says by dogging the Phoenician ships, and thus 
discovering the islands. 
As these ancient writers narrated events which must have taken 
place some six hundred years before their time, the value of 
such statements is often questioned, especially as no single article 
of undoubted Phoenician manufacture has ever been discovered in 
this country. If Phoenicians ever came here they have left no tan- 
gible traces of their presence, and grave doubts are raised in some 
quarters as to whether they ever traded here at all. Professor 
Rhys is one of the doubters, and he places the tin islands in Vigo 
Bay, on the coast of Spain. 
What is probably one of the most ancient blocks of tin in the 
world, is now in the Museum of the Royal Institution of Cornwall 
at Truro. It was dredged up about sixty-five years since near 
St. Mawes, at the entrance to Falmouth Harbour. An exhaustive 
description of this relic, by Colonel Sir Henry James, appears 
in the Forty-fifth Annual Report of the Royal Institution of 
Cornwall. This block is two feet eleven inches long, eleven 
inches wide, and three inches thick at the centre ; perfectly 
flat on one side, but curved on the other, and having four 
prolongations at the corners, each one foot long. Diodorus de- 
scribes the early tin ingots as being in the form of " astragali," 
and Professor Owen is quoted as the authority for the statement 
that this peculiar block is in the form of an astragalus, or 
knuckle bone. Sir Henry James very ingeniously accounts for 
the adoption of this shape by claiming for it a peculiar adapt- 
ability for stowage purposes in the bottom of a boat, and on a 
pack-saddle for land transport. No moulds of this form have as 
yet been discovered. 
Camden says the Greeks traded with Britain, and fixes the 
period at one hundred and sixty years before Caesar's invasion. 
Risdon is not so precise, but says no one doubts that they did 
trade here some time before the arrival of Julius Caesar. In 
Cornwall, at any rate, there is no doubt that Roman influence was 
extended toward tin-mining; for, at Castle Zen, in the parish of 
