XVI.] ADDITIONS TO GEOGRAPHY. 351

Yare at Yarmouth ; and finally our survey ends at the mouth of
the Thames, which in the text of Ptolemy (probably through an
error in writing) is called lamesa.

In Ptolemy's notice of Ireland in like manner- the number
of the places that are mentioned gives evidence of
an increased knowledge of that island on the part
of the Romans during the period subsequent to the Augustan
age1 ; and this confirms the statement of Tacitus in the Agricola,
to the effect that its trade and communication with the sister
island had increased in that interval3. There are but few of the
names which he gives, however, that we can identify with any
certainty, and these are mainly river-names on the eastern coast.
The Logia of Ptolemy is probably the Lagan at Belfast, the
Buvinda is the Boyne, the Oboca is the Avoca in Wicklow;
and the Birgus corresponds both in position and name to the
Barrow, which flows into Waterford Harbour. But Ptolemy's
knowledge of the position of Ireland relatively to England is
a great advance on that of Strabo and others, who placed it
to the northward of the latter island.

We may now proceed to notice the principal additions which
Ptolemy made to the map of the world in other

/ T „ i f Other Addi-

countnes. In eastern Europe he mentions for tionstoGeo-

the first time by name the Carpathians (Mons
Carpatis), with the existence of which the Romans
had become acquainted through Trajan's conquest of Dacia;
and he rightly fixes them as the boundary between that country
and Sarmatia8. The great river Volga also, the
absence of all notice of which in the works of
former geographers is so remarkable, here appears
under the name of Rha, and is described as discharging its waters
into the Hyrcanian or Caspian Sea*. In his account of Asia we
meet with the earliest notice of the great Altai
chain, which, commencing from the central group
of the Pamirs, diverges from the Himalaya, and
1 Ptol. 2. 2.
* Tac. Agrie. 24; melius aditus portusque per commercia et negotiators
cogniti.
8 Ptol. 3. 5. 6. 4 5. 9. ift, 13.