Intelligence and Miscellaneous Articles. 79 



the following passage from the work of M. Mazois, Les Ruines de 

 Pompeii, torn. ii. p. 77 : — 



" If the question of the employment of window-glass by the 

 ancients were still doubtful, we should find in this hall evidence 

 fitted to solve it ; time has spared here a glazed bronze window-frame 

 which determines not only the size and thickness of the glasses 



employed, but likewise the manner of fitting them ; These 



glasses were placed in a groove and held from place to place by nuts 

 which turned down upon the glasses to fix them ; their width is 

 about 20 inches, by 28 inches in height, and their thickness more 

 than 2 lines." 



Having ascertained the employment of window-glass at a period 

 anterior to the year 79 of our era, which is the date of the eruption 

 by which Herculaneum and Pompeii were destroyed, it becomes very 

 interesting to learn how these large panes of glass were manufactured 

 — whether they had been blown in cylinders or in disks, or cast 

 in the manner of plate glass. If blown, they could not have been 

 the product of a single dipping of glass ; and in this case the different 

 dippings would be recognizable on the edge of the glass. If they 

 were produced by blowing a cylinder and cutting it open, the bubbles 

 contained in them would be elongated and parallel in the direction 

 of the axis of the cylinder ; and they would be concentric if the glass 

 were produced in the manner of crown glass. If the glass were 

 cast, the bubbles would have no uniform direction, and would gene- 

 rally be round and flat. The author obtained some fragments of the 

 glass, measuring not less than 10 centimetres, the examination of 

 which left no doubt as to the mode of their manufacture. 



The glass is well fused, free from knots and other defects ; some 

 parts are free from bubbles, whilst great numbers occur in other 

 portions, but they are not all due to the fusion. The thickness 

 of the glass is unequal ; it is more than 5 millimetres in some places ; 

 in others not 3. This alone would indicate that the glass was not 

 blown. One surface bears the impression of the slab on which 

 the glass reposed when hot ; this might be the mark of the stone on 

 which the cylinder was opened out ; but the other surface does not 

 resemble that produced by blowing : other more certain signs that 

 the glass was not blown are furnished by the bubbles, which are not 

 those of a cylinder, nor of a globe opened out into a disk. Each glass 

 has evidently been cast : the casting in certain parts has not quite 

 reached its proper limit ; in others, on the contrary, the workman 

 having arrived near the limit, has turned back by folding the glass 

 upon itself, and thus there has been interposition of air, and forma- 

 tion of a stratum of bubbles. The irregularity of thickness proves 

 that a metallic cylinder was not employed to press upon the glass. 



It seems probable therefore that a metal frame of the size of the 

 pane of glass to be produced was placed upon a polished stone, on 

 which a little very finely powdered clay was sprinkled ; into this 

 frame was poured glass extracted from the melting pot with bronze 

 ladles or even with tubes, and the glass was pressed with a wooden 

 pallet to make it fill the interior of the frame. The ancients were 

 consequently very near the invention of plate glass, which only took 



