496 
PROFESSOR W. N. HARTLEY ON THE 
O'l grm. in 40 cub. centims. of alcohol of sp. gr. 0'8. 
This solution was kept for some time previous to being photographed. 
Thickness of 
layer of liquid. 
Description of Spectrum. 
Wave-lengths. 
mil ; ims. 
5 
Very faint to. 
4237 
4 
Paint to. 
4237 
3 
Weak, continuous to. 
4237 
Spectrum extends to. 
3982 
2 
Continuous to. 
3982 
Faint to. 
3600 
1 
Continuous to. 
3456 
O'l grm. in 40 cub. centims. of alcohol of sp. gr. 0*8, diluted 2 cub. centims. 
to 10 cub. centims. or 1 in 2000. 
Thickness of 
layer of liquid. 
Description of spectrum. 
Wave-lengths. 
millims. 
5 
Continuous to. 
3456 
4 
Continuous to. 
3340 
3 
Continuous to. 
3324 
2 
Continuous to. 
3002 
1 
Continuous to. 
2740 
O'l grm. in 40 cub. centims. of alcohol of sp. gr. O'8, diluted to 1 in 2000, again 
diluted 2 cub. centims.to 10 cub. centims. or 1 in 10,000. 
Thickness of 
layer of liquid. 
Description of spectrum. 
Wave-lengths. 
millims. 
5 
Continuous to. 
2740 
4 
Weak, continuous to. 
2568 
3 
Same as last spectrum. 
2 
Rays transmitted to. 
2568 
1 
Continuous to. 
2545 
Absorbtion band, from. 
2545 to 2343 
Rays transmitted faintly to ... 
2265 
