17 
TAB. CCIX. 
ARGILLA electrica. 
Tourmaline, or Schor!. 
Class 2. Earths. Order 1. Homogeneous. 
Gen. 4. Argilla. Spec. __ electrical. 
Syn. Tourmaline. Kirw. 1. 271. 
Le Schorl. Broch. 1. 226. 
Schwarzer Schorl. Lmmerl. 1. 95. 
Tourmaline. Hawy, 3.31. 
Borax electricus. Linn. Syst. Nat. ed. 12. 
ty os, 96. 
‘Tuts substance I have received from my friends Dr. Penneck 
and Mr. Dunkin of Penzance, found in that neighbourhood ; 
and I have gathered some curious curvilinear varieties of it 
at the Logan Rock. I have also been favoured with some 
aggregated kinds, by the Rev. Mr. Neck, from Devonshire. 
The specimen here figured was received from the former 
gentleman, and is somewhat remarkable for the largeness 
of the crystals *, though they are somewhat confused ; but 
more so still, from one end passing by fine straight fibres 
into the Quartz which accompanies it, giving it an ap- 
* The crystals are found more perfect at the Brazils, in Spain, Switzer- 
land, &c. 
VOL, III. Cc 
