[ 2 3 6 3 
are fuch, as he could not fee, or neglected to ob- 
ierve. 
The fourth ftone I have fent, which forms part 
of a circle, broke off from a ftone flat at one end, is 
the fpherical part of a ffone, fuch as it appears to- 
wards the concave end of one already mention’d. 
From thefe obfervations, thole, who are well 
verfed in natural philofophy, may poflibly form fome 
better judgment, and be more happy in their con- 
jectures in relation to this difficult lubjeCt, the caufc 
of the joints in the pillars of this extraordinary work 
of nature. 
Tab. X. 
Reprefents the plan and profile of the flones brought 
to Dublin by the Rev. Archdeacon Pococke. 
Explanation of the Figures 
Fig. i. A plan of the pillar, with the meafures of 
the lengths of the fides, A , B y G, D. 
Fig. 2* A plan of the pillar, with the lengths of the 
other four fides ; viz. f£, F, G, H y and the di- 
ffances of the circle from the fides of the polygon. 
Fig. 3. A profile of the ffones, fhewing the fides 
A, B, C, D. 
Fig. 4. A profile fhewing the fides £, F, G, H. 
The black lines fhew the deviation of the circles 
from a plane : and the large prick'd waved lines 
fhew the profile of the fwelling and concavity 
within them. 
The upper row of figures in each ftone fhews the 
heights of the fides at the angles fo far as they 
are ft r ait. 
The 
