Note 61 — Chapter I
Reading edition
To each object is attached a number denoting the exact depth in meters at which it was found; so e.g. 3½ M. means 3½ meters; each meter has about 3⅓ feet. I call particular attention to this. In order to retain the precision of these numbers, and to avoid the labour and chance of error in converting them into feet and inches, a comparative table of French and English measures is prefixed to the book.