Factitious Fuzxolana* 
dace the cost of the article, which was already one half 
less than that of Italy, and the public were about to en- 
joy the advantages of this manufacture, when the revolu- 
tion paralysed every tiling. 
In 1791 I informed the constituent assembly of this 
discovery; the certificates which proved it, and the 
results of the experiments were deposited at the of- 
fice ; the matter was ordered to be examined by M. M. 
Pelletier and Berthollet, and the assembly considering, 
that this factitious puzzolana might be of the greatest use 
to France, decreed that two thousand francs should be 
granted to its author, which were paid accordingly. 
On this occasion the celebrated Mirabeau declared 
the discovery to be so valuable, 66 that if it had not yet 
been made , public encouragement should be held out to 
excite it.” 
The Constituent Assembly wished to have numerous 
similar establishments set on foot in France, so well were 
they convinced of its national importance; but the mis- 
fortunes of the times prevented the execution of a project, 
which the grand chief of the empire may easily realize, 
to the advantage of the country, whenever it seems good 
to him to do so. 
Researches on the amelioration of our cements, and 
particularly on the nature of the materials proper to form 
artificial puzzolana, led me to try the calcination of va- 
rious schists, of the bitumenous, ferruginous, and argilla- 
ceous sorts. 
The black slatey schist of M. Bragge, so common in 
France, was not forgotten : It is almost the same as that 
which the elder M. Grathieu essayed at Cherboug last 
year ; but I have constantly found that these schists al- 
ways contain too little iron. I perceived that their re- 
pulsion of the water was slow and feeble, and that their 
