C 279 ) 
ference of upper and lower faperficies. Now that f have upon this 
occafion mention'd equifetum, give me leave to mindl you of what I 
have already publifli'd to the world;That I have found,on the banks 
of the river tamr in Tiedmont^ plenty of the fragments of the flalks 
of equifetum pcrfedly petrified,wirh licleor noincreafeof bulk,fo 
exaftly like the planc,that all the Jiru did all along clearly appear^ 
The colour of thefe petrified ftalks was whice» 
Jccowpt of tm B<^(/ks : 
I. Les dix Livrer JrchiteUure de VirRUVEy corrtgez^ 
trdduits nmveUemmt en Frumois , avec da Notes des. 
Figures ; p^^r Claude Perraulr , de I' Jcademie Royale des 
Sciences y ^M^decin^deU FacuUi de Paris. Imprimi i 
Paris, 1673. i^/f/. 
THE Ingenious and Learned Author of this Verfion of Fi' 
truviusy and of the Notes upon him, confidering with him- 
felf, that one of the Obftacles to the advancement of Architefture 
was the want of being able to draw the Precepts of that Art out 
of its true and genuine fource, by reafon of the great obfcurity of 
Vitruvim , who is the only Writer of the Antiencs that we have up- 
on this fubjed j did undertake, by a Tranfiation into the French 
tongue, and by Notes upon the difficult places , and alfo by il- 
luftrating all with Figures, to render this Author more clear and 
ufeful 16 thofe, that embrace the profeflion and pradice of that 
Noble Art, 
This Interpreter found, that in effefimoft of the matters con- 
tained in VitYwvtu4 being fo little underftcod as they are, had need 
of an Explication more clear and more exaft than the Text we 
have remaining^ forafmuch as the Author did not , in his opi- 
nion, fo much endeavour to make it clear as fuccind-, in the con- 
fidence he had that the Figures , added by him would fufficiently 
explain the matter, and thereby fupply what feems to be wanting 
in the Difcourfe. 
T^tft Figures^ faith M.PwW^, were loft by the negligence 
of the firft Tranfcribers, that could not defign, and that probably 
* alfo did not judge them altogether fo neceffary ; becaufe the con- 
Oo 2 templaticn 
