39G 
Farming of Dorsctslnre. 
consists of tav and water, impregnated with ammonia. If tlie 
former be subjected to a second distillation in a cast-iron still, 
it will furnish about 50 per cent, of a tliin volatile fluid, analo- 
gous to naphtha obtained from coal-tar, and about 50 per cent, of 
a dense oil, boiling at a A ery high temperature. The first of 
these, rectified by distillation with water, yields a very fine 
light oil, or spirit, quite colourless, extremely volatile, and suit- 
able for the same purposes for which coal-naphtha is generally 
employed. The dense oil, purified by successive distillations, 
arrives at the consistency of sperm, and at a light amber colour. 
It possesses extraordinary properties as a lubricant, particularly 
for light and delicate machinery. It is probable also that it 
might be rendered useful for burning in lamps. The residue of 
shale is a porous kind of coke, consisting of alumina mixed with 
finely-divided carbon. It is this which has been used, though 
not by any means extensively, for manure. The following- 
figures show the relative proportions of the products obtained in 
the distillation of shale rich in bituminous matters : — 
Coke I 
earthy matter 61 G 
carbon 7 ■ 7 
Water C-4 
Oil 14-5 
Tar. Naphtha 9-8 
100 
The shale w'ill probably be ere long employed as a deodorizer 
of foetid matters. Bands of limestone interspersed among the 
shale are broken up and conveyed to the Isle of Wight, where it 
is manufactured into cement. 
Yet however interesting to the geological observer the county 
of Dorset may be, Ave have to regard it in a purely utilitarian 
point of view, and to look upon its various strata as containing 
not simply the fossils of bygone ages, but chiefly tlie elements 
Avhicli may produce subsistence for the present and future gene- 
rations. The geological map and sections which accompany 
this paper, and for Avhich I OAve my Avarmest thanks to my friend 
Mr. H. B. Bristowe, of the Government Geological SurAey, by 
Aviiom the county Avas recently surveyed, express Avith minute 
accuracy the geological features of the county ; and if any one 
Avho feels an interest in folloAving up this subject will but com- 
pare the map at the head of this paper (reduced by Mr. BristoAve 
from that published by the Government Survey) with the map 
prefixed to ' Stevenson's Report on the Agriculture of Dorset in 
1815,' or even with Dr. Buckland's famous BridgeAvater Treatise 
— high authority as that is — he Avill note Avith Avhat care the 
mapping of the geology of this county has now been effected. 
