ADDITIONAL DATA. 



two maxima. But, when one considers that the bands are wide and 

 completely opaque as found by transmission, while they are very weak 

 as found by reflection (maxima only 7 and 12 per cent), and that they 

 were made by different observers with different instruments, it is not 

 straining matters to consider them to be due to the same ion. For 

 KNO 3 , Pfund found the maximum at 7.05 /* (on the published curve it 

 appears to be 7.1 //.), while the writer found the same band at 7.14^, so 

 that the discrepancy noted above is more likely to be due to a difference 

 in our calibration curves. Then, too, the maxima found by reflection 

 and by transmission should differ with the latter lying toward the 

 shorter wave-lengths. Whether a gas can have selective reflection will 

 depend mostly upon its extinction coefficient. To examine its reflecting 

 power in its liquid state will be almost impossible because of the dense 

 vapor above its surface. 



TABLE IV. 



Reflection maxima. 



NaK tartrate, KNaC 8 H 4 O 6 4-4H 2 O.. 



Magnesium nitrate, Mg(NO 3 ) 2 -j-6H 2 O 



Cobalt nitrate, Co(NO 3 ) 2 +6H 2 O 



Ammonium nitrate, NH 4 NO 3 



Calcium nitrate, Ca(NO 3 ) 2 -f-4H 2 O 



Silver nitrai e, AgNO 3 



Potassium nitrate, KNO-, 



Nickel sulphate, NiSO 4 +7H. 2 O 



Cobalt sulphate, CoSO 4 -f7H 2 O 



Copper sulphate, CuSO 4 -|-5H 2 O 



Cadmium sulphate, CdSO 4 +4H 2 O 



Ferric sulphate, Fe 2 (So 4 ) 3 +9H 2 O 



Sodium, Na 2 SO 4 +ioH 2 O 



Potassium, K 2 SO 4 



Fuming sulphuric acid and water, H 2 SO 4 -f SO 3 



Nitric acid, HNO 3 



Glycerin. C 3 H 8 O 3 



Na silicate, Na 2 SiO 3 



Nitrosodimethyl-aniline, (CH 3 ) 2 NC 6 H 4 NO 



7-45 

 7-45 

 745 

 745 

 7 45 

 705 

 905 

 9.05 



9-15 

 9.10 



9.05 



9.02 



8.85 



(7.25 



18.6 



7.85 

 4.80 



9 95 

 7.4 



8 6 10.35 

 96 n-35 

 10-55 

 9.70 



9.0 



It is generally conceded that when a gas is dissolved in a liquid, part 

 of the gas goes into solution, part will be actually liquefied, while part 

 may enter into chemical combination with the liquid. Since change of 

 state does not affect the absorption (reflection) bands, it would appear 

 feasible to examine the reflecting power of gases by this method. How- 

 ever, the question of the solubility of gases in different liquids is also 

 a quite unexplored field, so that the investigator would first have to 

 search for proper solvents. 



