Configurations of Alum. 99 
Each of thefe Lines increafing in Breadth 
towards its End, appears fomewhat club¬ 
headed, as e e e. 
Sometimes inflead of fending Branches 
from their Sides, many of thefe Lines rife 
parallel to each other, refembling a Kind of 
Palifadoe, and having numberlefs minute 
tranfverfe Lines running between them, as 
at F. ' 
But the mofi wonderful Part of all, tho* 
not produceable without an exadl Degree 
of Heat and right Management, is the dark 
Ground-work fhewn at G, which confifts of 
an almoft Infinity of parallel Lines, having 
others eroding them at right Angles, and 
producing a Variety fcarce conceivable from 
Lines dilpofed in no other Manner: the 
Dire&ion of the Lines (which are exqui-t 
iitely ftrait and delicate) being fo frequently 
and differently counter-changed, that one 
would think it the Refult of long Study and 
Contrivance. 
During the Time this Ground-work is 
forming, certain lucid Points prefent them- 
felves to view (on one Side thereof moll 
commonly) which Points grow larger con¬ 
tinually, with Radiations from a Center, 
and become Star-like Figures, in the Man¬ 
ner of thofe before mentioned. Several of 
them likewife fhoot out long Tails, which 
give them the Appearance of Comets : and 
at the End of all, a dark Lineation, in 
H 2 various 
