AND TRANSMITTED BY CERTAIN KINDS OF GLASS. 
275 
Table XIII. —continued. 
Per cent, of 
Xi. 
(x - Xi). 
X2. 
(x — X 2 .) 
incident light 
transmitted. 
11-5 mm. plate his (continued). 
187-4 
August 13.—Repolished with fine rouge on 
197-2 
198-2 
186-4 
89-37 
silk, and subsequently (11/8/88) with 
187-9 
196-7 
198-2 
186-4 
89-84 
putty powder on wood disk 
188-7 
196-9 
198-3 
186-3 
90-03 
]\Iean 
89-75 
1.5 mm. plate. 
July 6.—Cleaned, but not repoli.shed . . . 
125-6 
1.36-4 
133-2 
128-8 
89-04 
126-1 
135-9 
133-6 
128-4 
89-18 
126-2 
135-8 
133-3 
128-7 
89-72 
Mean 
89-31 
July 1.3.—“ Ground grey and repolished ” 
125-3 
136-7 
1.34-1 
127-9 
87-42 
by Mr. Huger 
125-6 
136-4 
133-6 
128-4 
88-50 
126-1 
135-9 
183-9 
128-1 
88-77 
Mean 
88-23 
July 17.—Re-examined. 
124-8 
137-2 
132-2 
129-8 
89-31 
124-8 
137-2 
1.32-5 
129-5 
88-90 
124-9 
137-1 
132-7 
129-3 
88-77 
Mean 
88-99 
August 17.—Repolished with putty powder 
185-4 
199-1 
197-1 
187-4 
88-54 
on wood disk 
185-5 
199-0 
197-0 
187-5 
88-72 
185-6 
198-9 
196-9 
187-6 
88-90 
Mean 
88-72 
18'5 mm. plate. 
128-6 
July 16. — Cleaned, but not repolished 
125-4 
136-5 
1.33-3 
88-63 
124-9 
137-0 
133-1 
128-8 
88-22 
Mean 
88-41 
July 17.—Re-examined. 
123-5 
138-4 
131-6 
130-3 
88-35 
123-6 
138-3 
1.3T6 
130-3 
88-49 
124-4 
137-5 
131-8 
130-7 
89-72 
Mean 
88-85 
August 17.—Re-examined. 
184-6 
199-8 
197-2 
187-2 
87-71 
185-7 
198-7 
196-5 
187-9 
89-37 
185-2 
199-2 
197-4 
187-0 
88-07 
Mean 
88-38 
2 N 2 
