[ 6o 5 ] 
the fame thing ; and thought to have been nothing 
but a kind of white tranfparent talc, of which (ac- 
cording to Monf. (16) Valois) there is found a great 
quantity in Mofcovy at this day. 
Now that this lapis fpecularis , or phengites, was 
really ufed for windows by the ancient Romans in their 
houfes, &c. cannot be denied ; fince (according to the 
opinion of the learned (17) in antiquity) this ufage 
is mentioned by Seneca (18) among other improve- 
ments in luxury introduced in his time. But whe- 
ther it was fo ufed exclufive of other materials (par- 
ticularly glafs), may, I think, admit a doubt. Sal- 
mafius is of opinion (19), that nothing can be de- 
termined upon this point from the word fpecular it- 
felf, which feems to be a. generical term, equally 
applicable to windows of all kinds, whether confift- 
ing of the lapis Jpccularis , or any other tranfparent 
fubifance. 
And as (according to this learned writer) there is 
nothing in the term fpecular itfelf, which hinders it 
from being extended to windows made of other ma- 
(16) Hift. de 1 ’Acad. des Infcrip. tom. I. 
(17) Montfauc. Antiq. vol. III. part i. lib. iii. c. 4. Lipfius in 
loc. &c. 
(18) Qua dam nojlrd dentum prodiijje memorid fchnus ; ut fpecu- 
lar iorum ufurn , perlucente tejld , clarnm tranfmittentium lumen. Sen. 
ep. 90. 
(19) Quod fencjlrls obducebatur ad tranfucendum, ac lucem ad- 
mittendam fpecular vetens Latini vocarunt. Idque ex fpeculari la- 
pide, qul {ft ipeyyirnf, aut ex vitro fiebat , aut alia tranflucidd ma- 
teria. Nam fpecular didtum, non quod ex fpeculari lapide fafiu?n 
ejfet,fed quod vifum tranfmitteret , ac per id fpeculari lieeret. Salm. 
Exerc. Plin. in Solin. tom. II. p. 771. 
terials 
