422 Scientific Intelligence. 
t 
may also be mentioned that none of the measurements (of the distances 
80 
made until each member of the table had been calculated as it stands be- 
low. Whatever the experiments may be worth therefore, they have at 
least the merit of being entirely independent and wholly unbiassed. 
Description of glass. Thickness of glass. "Loss of light. 
Thick English plate, 4 of an inch, 6°15 per cent. 
Crystal plate, 4 “ = - S:8 ie", 
English crown, 4 6 - + dO OS. de 
“ Double English,” window glass, 4 Sad feces eee 
“ Double German,”+ . 4 & - => deo 329 
“ Single German,”+ . vs a on Se ae ae 
Double German,t ground,t 4 oS pe 5 Oe 
Single German,+ ground,t rs “y - =. COND 
Berkshire, (Mass.,) ground,f vs * - mo MAME A Me cee 
erkshire enameled, i.e., ground 
only upon portions of its sur- as . - «,, OL2S i. = 
face,—small figure, 
“ Orange-colored” window glass, vs 34:48. “ 
, Purple” 2 $ As used for church 85:11 i 
. Ruby” o “ ais } windows, &c. 89:62. = 
“ Green” . «“ a SPOT as 
A porcelain transparency, (Ty- , “ 
rolese Haat y" y» (Ty t te Wahaer - 97°68 
The term “ loss of light” employed by Mr. King does not at first sight 
seem to be strictly appropriate, for a very considerable portion of the light 
not transmitted by a glass shade might be reflected against the walls of 
wg vith the ordinary chimney.—Mr, King does not specify what burner was 
used in his experiments, but it was robably the “fish-tail,” which has been so 
tandard by his father, consuming four feet per hour, © 
ur 
} The enormous resistance to the passage of light which is offered by ground 
glass is certainly worthy the attention of those using it for windows, é&c. 
1 screpancy between Mr. King’s results and my own as regards ground glass 
may perhaps be owing to the fact, that the window glass used by myself was more 
coarsely ground than the lamp shades employed by him. 
