de la statistique_, and wrote in
German _Die Bevolkerung des franzosischen Kaiserreichs_ (1861); Die
Bevolkerung Spaniens und Portugals_ (1861); and _Die Machtstellung der
europaischen Staaten_ (1862).

BLOCK (from the Fr. _bloc_, and possibly connected with an Old Ger.
_Block_, obstruction, cf. "baulk"), a piece of wood. The word is used in
various senses, e.g. the block upon which people were beheaded, the
block or mould upon which a hat is shaped, a pulley-block, a
printing-block, &c. From the sense of a solid mass comes the expression,
a "block" of houses, i.e. a rectangular space covered with houses and
bounded by four streets. From the sense of "obstruction" comes a "block"
in traffic, a block in any proceedings, and the block system of
signalling on railways.

BLOCKADE (Fr. _blocus_, Ger. _Blokade_), a term used in maritime
warfare. Originally a blockade by sea was probably nothing more than the
equivalent in maritime warfare of a blockade or siege on land in which
the army investing the blockaded or besieged place is in actual physical
possession of a zone through which it can prevent and forbid ingress and
egress. An attempt to cross such a zone without the consent of the
investing army would be an act of hostility against the besiegers. A
maritime blockade, when it formed part of a siege, would obviously also
be a close blockade, being part of the military cordon drawn round the
besieged place. Even from the first, however, differences would begin to
grow up in the conditions arising out of the operations on land and on
sea. Thus whereas conveying merchandise across military lines would be a
deliberate act of hostility against the investing force, a neutral ship
which had sailed in ignorance of the blockade for the blockaded place
might in good faith cross the blockade line without committing a hostile
act against the investing force. With the development of recognition of
neutral rights the involuntary character of the breach would be taken
into account, and notice to neutral states and to approaching vessels
would come into use. With the employment in warfare of larger vessels in
the place of the more numerous small ones of an earlier age, notice,
moreover, would tend to take the place of _de facto_ investment, and at
a time when communication between governments was still slow and
precarious, such notice would sometimes be given as a possible measure
of belligerent tactics before the blockade