96 BASALT. 
The former,, which ia- believed by the common people- 
to have been an artificial production, the vast labour of 
giants who formerly inhabited the countiy, consists of 
an irregular group of many thousand jointed pillars. 
Most of these are of considerable height ; are in ge- 
neral five-sided., fifte.en or sixteen inches in diameter, 
and each perfectly distinct from top to bottom, though 
so closely and compactly arranged that it is scarcely 
possible to introduce any thing betwixt them. This 
assemblage of columns extends into the sea to a dis- 
tance unknown, and along a tract of the sea coast of 
nearly six miles. 
The Cave of Fingal is accessible only by sea, and is 
formed by ranges of massive basaltic columns, fifty feet 
and upwards in height. The stone of which these co- 
lumns are formed very much resembles that of the 
Giants' Causeway. 
In several parts of the world large masses of basalt 
are discovered, composing entire insulated mountains, 
of somewhat conical form. They are considered by 
some writers as volcanic productions, but the proofs of 
this are by no means satisfactory. 
Amongst the uses to which basalt has been applied, 
two of the most important are as materials of an excel- 
lent and durable kind for building and paving. When 
burned and pulverized,, these stories impart to mortar 
with which they are mixed the property of hardening 
under water. They. easily melt, wilhout any addition, 
into an opaque and black glass ; and from them, under 
a certain modification, bottles of olive-green colour, and 
of extreme lightness, but great stremgtk sd solidity, 
have been formed. Some of the kinds have bees ad- 
vantageously employed as millstones-. Basalt is occa- 
sionally used by artists for touch or teststones, to as- 
certain the purity of gold and salver ; and goldbeaters 
and bookbinders, on the Continent, usually m&ke their 
anvils or beating blocks of k. 
Basalt, though harder, more brittle, and less phasing 
in its colours than marble, was in considerable esteem 
