540 PHILOSOPHICAL TRANSACTIONS. [anNOI/GS. 



observes that Mabillon mentions a manuscript he saw in an abbey in the diocese 

 of Freisingen^ where Ptolemy was represented observing the stars with a tube, 

 like our modern perspective glasses. This manuscript is said to have been 

 written in the beginning of the 13th century. Mabillon does not mention that 

 the tube had glasses ; neither indeed was that circumstance easily discoverable. 

 Perhaps such tubes were then used only to preser\'e and direct the sight, or to 

 render it more distinct, by singling out the particular object looked at, and 

 shutting out all the rays reflected from others, whose proximity might have ren- 

 dered the image less precise. 



As it appears that neither the lapis specularis nor glass was used for windows 

 before Seneca's time; and it cannot be supposed that the Romans, a people of 

 so refined a taste in other instances, would suffer their apartments to be exposed 

 to the free entrance of winds, &c. it may be reasonably asked, what supplied the 

 place of those materials before? To satisfy this inquiry, it is to be observed that 

 several other materials are mentioned by ancient writers, as serving the purpose 

 before us ; such as thin hides or skins, like our parchment, mentioned by Phi- 

 loponus. Pliny likewise informs us that the horns of the urus being cut into 

 thin laminae, were transparent, and supplied in some measure the use of our 

 lanterns; and we may probably conclude, from the analogy of things, that they 

 served for window-lights also ; especially as we meet with windows made of horn 

 (corneum specular) in Tertullian, who wrote within less than 200 years after 

 Pliny. To these may be added the vela, made of hair-cloth, or pieces of hides, 

 which Pitiscus, on the authority of Ulpian, says were in use before the inven- 

 tion of windows of the lapis specularis or glass. 



Mr. N. took notice of the natural connection there seemed to subsist between 

 the using of plates of glass for adorning the inside of apartments in ancient times, 

 and the employing them for introducing light into those apartments. This ob- 

 servation has been supported by a letter he received from the Abbate Venuti at 

 Rome, dated December 30, 1759, wherein he informs him that he had lately 

 read in some anecdotes of Cardinal Maximi, ' That as they were digging among 

 the ruins on mount Caelius in the last century, tliey found a room belonging 

 to an antique dwelling-house, that had all its sides within ornamented with plates 

 of glass, some of them tinged with various colours, others of their own natural 

 hue, which was dusky, occasioned by the thickness of the mass of which they 

 consisted. There were likewise in the same apartment window-frames composed 

 of marble, and glazed with laminae of glass.' 



Presuming the evidence to be undeniable which Mr. N. has produced in his 

 dissertation, to prove the use of glass in windows to have been as early as the 3d 

 century, if not* before, he deems it not unacceptable to the curious in antiquity 

 to observe the slow progress this very commodious invention made towards the 



