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XXI. An Account offome Obfervations relat- 
ing to the Production of the Terra Tripo- 
litana, or Tripoli. Humbly addreffed to 
the Royal Society of London, by Martin 
Hubner, Fellow of the faid Society , Profef- 
for of Hijlory in the Univerfty of Copen- 
hagen, and Member of the Royal Academy 
of Infcriptions and Belles Lettres of Paris. 
franjlated from the French, by Emanuel 
Mendes da Coda, F. R. S. 
Read June 21, T^U RING a journey I made, in the 
1759 I J autumn of the year 1755, through 
feveral provinces of France, principally in Britany, I 
made the natural hiftory of that province, which 
has plenty of productions worthy the attention of a 
naturalift, one of the objeCts of my refearches. The 
lead mines of Pouillauen in the Lower, and thofe of 
Pontpean in the Upper Britany, employed me fome 
time. The metallic veins in thefe mines are not only- 
rich and regular, but alfo hold a great proportion of 
filver, which they do not extract with that profit, that 
might be done. In general, they could work thefe 
mines to greater advantage, if they were more fkil- 
ful, or had proper machines, and above all others 
the fire engine, which is ufed with fuch fuccefs in 
the mines of Cornwall to drain off the water, that ele- 
ment being the greateft obftacle to the right working 
of the mines of Britany : but the advantages of this 
invention, glorious to its fii ft difcovcrer, and ufefui, 
to 
