A1>1>. N a IX.] 
TECHNICAL TEll .MS. 
17 i 
A Lead. — A channel or passage among ice, nearly synoni- 
ttioiis with a “ lane of water,” but it may be more com¬ 
plex. Thus, a lane of water is always a “ clear lead,” 
but a lead may also be “ cross,” or bad, or dangerous. 
Light-ice . Thin ice, or ice not generally dangerous to 
shipping. The different terms bay-ice, light-ice, and 
heavy-ice, are distinguishable of various thicknesses. 
Thus bay-ice may be said to extend from the first pel¬ 
licle of ice formed on the water up to a foot in thick¬ 
ness ; or, in the case of floes, to a little greater thick¬ 
ness. Light-ice , from a foot to a yard, or at most a fa¬ 
thom in thickness ; and heavy ice, from about a fathom 
upwards. 
1 Loose-ice. —Open drift-ice, among which a ship may find a 
passage. 
Open-ice , or sailing-iee. Drift-ice or Hoes, so separated as 
to afford a convenient passage for ships. It differs lit¬ 
tle from loose-ice. 
Pack. —A body of drift-ice of such magnitude, that its ex¬ 
tent is not discernible. A pack is said to be open, when 
the pieces of ice, though very near each other, do not 
generally touch ; or close, when the pieces are in com¬ 
plete contact. 
Patch. —A collection of drift-ice or bat -ice of a circular or 
a polygonal form. In point of magnitude, a pack cor¬ 
responds with a field, and a patch with a floe. 
Rank-ice. —Crowded drift-ice. 
Sailing-ice —Open or loose ice. 
Sludge.—A stratum of detached ice-crystals, or of snow, or 
of the smaller fragments of brash-ice, floating the sur-. 
face of the sea. 
Stream- An oblong collection of pieces of drift-ice, or bay- 
ice, the pieces of which are continuous. It is called a 
