And again, on page 35:
It is, in fact, impossible to give, within the outer limits named, any distinct idea of where ice may be expected, and no rule can be laid down to insure safe navigation, as its position and the quantity met with differs so greatly in different seasons. Everything must depend upon the vigilance, caution, and skill with which a vessel is navigated when crossing the dangerous ice-bearing regions of the Atlantic Ocean.
Similar warnings as to ice are also given in the "Nova Scotia (Southeast Coast) and Bay of Fundy Pilot" (sixth edition, 1911), which is also published by the hydrographic office.
Both the above quoted books were supplied to the master of the Titanic (together with other necessary charts and books) before that ship left Southampton.
The above extracts show that it is quite incorrect to assume that icebergs had never been encountered or field ice observed so far south, at the particular time of year when the Titanic disaster occurred; but it is true to say that the field ice was certainly at that time farther south than it has been seen for many years.
It may be useful here to give some definitions of the various forms of ice to be met with in these latitudes, although there is frequently some confusion in their use.
An iceberg may be defined as a detached portion of a polar glacier carried out to sea. The ice of an iceberg formed from a glacier is of quite fresh water. Only about an eighth of its mass floats above the surface of sea water.
A "growler" is a colloquial term applied to icebergs of small mass, which therefore only show a small portion above the surface. It is not infrequently a berg which has turned over, and is therefore showing what has been termed "black ice" or, more correctly, dark-blue ice.
Pack ice is the floating ice which covers wide areas of the polar seas, broken into large pieces, which are driven ("packed") together by wind and current, so as to form a practically continuous sheet. Such ice is generally frozen from sea water, and not derived from glaciers.
Field ice is a term usually applied to frozen sea water floating in much looser form than pack ice.