IS 



COMPASISON OF >TW V.-TTH OLD GLASS. 

 A few lesT - r.r 



il . :^ glass wa5 . 1 wiLh 



were •:€ thr^e ' _ n an av- r : /', 



New, s . -30 



Old- se - fe glass, .26 



lo- r 



The 'rid siass was takes, frcn: a hoiise w:;- 

 5,-- - . - - _• ■ ■--- clean. ~; 



n'. . - . . : to ten'. . : '"iv^ 



the old. 



A siirriilar e:sreriTDeni was cc^'iicred in two h : 

 R - - _ :_ ^' :k. Mass. C- ^- . . ^. : v 



i "TV years £c: . f of the elai 



oceervaSjp::, 5-iIL S percent, is a rather insigiiifecant p- - 

 ccdsice-ring tl^ iength ot ----- -'-.e older glass had te-.:- _-. 1. 



^lanv lactG&s enter into a of this nanire. such as diast, 



■.riven above is in -Dart due to the ac:- : lust at ' 



— ner; _ rcent. 



