24 ® 
Factitious Puzzohna, 
The discovery which I here present, has, like many 
others of great utility, been the effect of chance. 
The habit of examining the nature of stone in its bed, 
which enables the observer to judge of its qualities at 
first sight, fixed my attention on an immense quantity of 
calciform fragments of iron ore, in beds of from eight to 
ten feet thickness, following exactly the parallelism of 
the slightly inclined declivities, in the neighbourhood of 
Castlenaudery. I perceived in the adjacent fields many 
substances of the same nature scattered over the surface 
of the earth, of violet, brown, and black colours, which 
from their appearance, had a perfect resemblance to 
compact lava, which seemed extraordinary in a country 
where there was no appearance of ancient craters, or of 
volcanic eruptions. These I soon found out had been 
brought to tliis state by serving as hearths, or enclosures 
to the fires kindled in the fields by the peasants, either 
for agricultural purposes, or personal convenience when 
they watch their flocks in winter; as I saw soon after, 
many similar arranged by hand on one another for these 
purposes. 
The similarity of these fragments to volcanic products 
excited my desire to form a cement from them, by treat- 
ing them in the same manner as puzzolana earth. The 
great quantity of iron which these oxides seemed to me 
to contain, the abundance of their siliceous particles, and 
the alumen which evidently entered into their composi- 
tion, their great weight, and their non-effervescence with 
acids, altogether made me presume, that the cement 
formed from them would bind under water, and my ex- 
pectation was not deceived. 
Fifteen months successive experiments, to discover the 
proportion of lime which this oxide would absorb to har- 
den in w ater, without cracking when in the air, have con 
vinced me, that my factitious puzzolana had all the good 
