1909.] OF VARIOUS SALTS IN SOLUTION. 225 



AA 5010 and 5350 and AA 5660 and 5985. The widening of the latter 

 band is distinctly unsymmetrical. The existence of the band A 5320 

 causes the band A 5010 to A 5300 to widen unsymmetrically. 



The bands in the region A 6300 become less sharp as the tempera- 

 ture rises. At 11° there was considerable transmission in the region 

 A 6850. At 85°, however, this transmission disappears and there is 

 practically complete absorption from A 6760 to A 6920. The very 

 sharp bands AA4282, 4300, 4310, 4322 and 4343 do not appear to 

 change very much with change in temperature. On the strip taken 

 at yT,° these bands appear sharper than on any of the other strips. 



A spectrogram {B, Plate XL) showing the effect of rise in tem- 

 perature was made on a neodymium chloride solution in water of 

 C.17 normal concentration and a depth of layer of 196 mm. The 

 amount of neodymium chloride in the path of the light is approxi- 

 mately the same as in the spectrogram, showing the effect of tem- 

 perature upon a 3.4 normal concentration and a depth of cell of 12 

 mm. In this case the temperatures were 5°, 16°, 28°, 42°, 59°, 72° 

 and 82°. Exposures were made to the Nernst glower for 3 mm. 

 current 0.8 amperes and slit width 0.20 mm. Each strip was ex- 

 posed to the spark for 6 mm. The purpose of making this spec- 

 trogram was to find the efifect of concentration of a salt upon the 

 changes produced by change in temperature. 



A description of the bands at 5° and 82° will be given. Any 

 change between these two temperatures that takes place is a gradual 

 one. Transmission begins at A 2600. Bands appear between AA 3250 

 and 3300 and AA3455 and 3575. The band A 4274 is much sharper 

 and narrower than for the more concentrated solution. The nu- 

 merous fine bands in the region A 4300 are very faint. The bands 

 AA4420 to 4460, AA4600 to 4630, A 4645, AA4680 to 4705, AA4745 

 to 4770 and A 4820 have rather diffuse edges. Wide bands appear 

 from A 5020 to A 5290 and from A 5685 to A 5920. Diffuse bands 

 are located at A 53 10, A 68 10 and A 6900. The group in the region 

 A 6300 appear, but they are extremely faint. 



At 82° the general absorption has increased in the ultra-violet 

 and has reached to about A 2800. It will be noticed here that the 

 effect of rise in temperature is greater upon this general ultra-violet 



PROC. AMER. PHIL. SOC, XLVIII. I92 P, PRINTED SEPTEMBER 7, I909. 



