184 Foreign Literature and Science. 
PORCELAIN. 
Sevres. |England Piedmonts. Tournay. 
0.753 
: - =) | 0.596 | 0.970 0.600 7 
3 a z 086 0 0.082 
- : = pap ONS | — } 0.059 
: ‘ 6.024 | 0.012 0.016 0.100 
: 5 2 0.070 0.15: - 
The paste of Sévres is composed of 
-633 of kaolin of Limoges, washed ; 
-105 of quartzose sand from the mound of Aumont ; 
got of chalk from Bongiv 
210 of fine sand extracted friti the kaolin by washing ; 
this sand is a mixture of quartz and Sees 
Sévres is known of an excellent 
The por 
quality, and as refractory as any in Euro 
The glazing is made of a rock composed of quartz and 
feldspath, es toa fora we Dah It is composed of 
ilica, 
Alumine, - - - “ 768 
Potash, - - - ete 0.982 
Wa w é 
ter 
It melts into a perfectly transparent and colorless ck vape _— 
Annales des Mines. T. I. 4 
31. On the measure o o the intensity o Vode .—The most 
general method is to place an opake ree a iitte 
card or pastebord, in front of the two li hts to be examined, 
to remove the latter ‘from the screen until they produce ray 
sari over PDE teoen gu ae uildist tant from each shadow, 
tee will, if viewer 
