T. Gaffield on the action of Sunlight on Glass, 249 
The first table shows that twenty-four kinds were found to 
be easily affected, and exhibits the time at which the change in 
color was first observed. The second table shows nine kinds 
which did not change in color during the same time. 
Table of glasses easily changed. 
Kinds of Glass. | Original color before exposure. 
: of French white plate. White, with light bluish green tinge. 
German White “ “ “ “ 
5 * * English whitetplate Re er ye Sein 
P ello 
“ Belgian ssa plate. White, — slight green 
s “ig Sane whi te she et, th light pete: h green ‘ti 
h gree 
. “ ane oe One ight. ellowih pak and dase oe ght blu- 
1 ish gr 
| 2“ American® = « White, ger Tight blue green tinge. 
1 24 
4 ee 
; The time at which change a eer was first observed. 
Days. Wee Months. Color after exposure. 
al BEd +4 1 2 | 3 | 1} 2 
1 . Yellow or yellowish Breen. 
1 
1 “ “ 
4 1 Deeper yellow dase 
1 Yellowish green | tinge. 
3 
1 “ “ 
ak Ee 1 s 
=e 1 “ rt 
Soo! 6h 1) 8 | 2 I 
Table of Glasses not changed in three months. 
Kinds of glass. Original color of glass. 
ite eee ee 
1 kind of German crystal plate. t 
aS gua. 3 Dark blue. 
Si English rong Pa ark green. 
ss 42 Be English Light green. 
: a Peri pe pretees « Bluish green. 
e Pek t Dark bluish green. 
¥ : “ Ei lish “ Te green. 
a 1 Bott Belgian “ Yellowish or brownish green. 
e, Pa & vench a “ “ “ 
9 : 
se 
Subsequent experiments with five of these kinds, (all which 
[ oe eat obtain), showed that an exposure of a year, 
or even less, would change all but LS of Amencsn 
