458 Scientific Intelligence. 
this work, which has led me to rectify several numbers relatin 
to wave-lengths at the less-refrangible end of the spectrum; ri 
will only give here the wave-lengths of ae he lines used 
for reference: the band indicated by A” former memoir is 
made up of two bands, whose wave- onde i are from 0°00115 to 
0°00119 millim., and from 0°001132 to 0°001142 millim, ; the large 
band A” extends from 0°001351 to about 0°001400 millim., and 
the extreme band A from 0°001800 to about 0°001900 millim. 
for the first, and from 0°001239 to ‘ diese? for the eanelh 
e metals were volatilized in the voltaic are. The intensity 
was such, that I could make use of a very narrow slit, an 
observe, on the phosphorescent substance, interesting details. In 
this case, it is necessary that the image o of the line be brought to 
an exact focus on the phosphorescent screen ; for, onluas this be so, 
the results are not observable when the slit is narrow. 
spectrum; but, by i trials, it was possible ef — — 
examined. I am occupied, roe ver, sent striae with 
an improvement, which will admit of ‘till, greaen delicacy. 
Wave-lengths of the Principal Emission-rays of several Incandescent Metallic Vapors. 
POTASSIUM. ALUMINIUM. 
Wave-length, 1128 ) Broad and intense, perhaps 
1098 : : 4113615 compound. 
1162 Lines very brilliant, 
1233 1125 ZINC. 
1306 
Sopium. 
{ Visible to the nak 1850. CADMIUM. 
si9/ Capt. Abney has priya ee Leap. 
this line ie discovered that} 1059-8 
ouble. ae | Very intense. 
1142. 
Feebler group. 
rl STRONTIUM. 7a Approximate wave-length. 
ee Lines and bands feebler; ap- THALLIUM. 
jose]? proximate wave-lengths. 1150. Approximate wave-length. 
1098 
CALCIUM. aay se gets 
858-876 ) Broad bands, probably groups| 973 t Approximate wave-lengths. 
883-888 of lines. poeetl 
ar ot au t Visible to the naked eye. 
899 Very oe perhaps com-| 825 
1083 TIN 
1047 (2) J Very fe 1199 f 
1200 ) Broad Ans pitiiaie double. 
21 This group resembles group 0. 
