( 586 ) 



Nfodymbnn nitrate [Nd (NOJ^. 6 H,0]. The warer of orjstallisation 

 is expelled during moderate healing, and on cooling a (Ine rosy-red 

 amorphous transparent mass is retained, which remains unchanged 

 for some time. In course of time a kind of crystalline light foani 

 deposits on the surface and the walls of the test-tube attended by 

 absorption of water, which foam could he collected and be pressed 

 into thin tilms by the aid of zapon-varnish. 



The amorphous nitrate exhibited numerous bands, among which a 

 rather well defined one at about 625 (with companion 626). At — 193° 

 it had a breadth of 0,3, in a field of about 25 kilogauss one of 

 0,4 ft/f. By chance we noticed that the ci-ystalline nitrate foam at 

 - — 193° exhibits much narrower bands than an amorphous layer of 

 the same thickness; among others in the neighbourhood of D : 

 577.0, 578.7, 579.7, 5P2.0, 583.0 ; the three last of these have a 

 breadth of about 0,15 im ; in the field a very slight, hardly mea- 

 surable broadening seems to take place. The 5 sharply defined bands 

 in the green between 500 and 525 behave in an analagous manner. 



Neodymmm inagnesiuni nitrate [2Nd (N03)3. 3 Mg (NOj)^. 24 H,0]. 

 Yields analogous products when treated as before. 



It has a very complex absorption spectrum with a great number 

 of narrow bands, which are very pronounced particularly at the 

 temperature of liquid air. Particularly worth mentioning is the 

 following, observed with a thickness of about 10 m.m. of the amor- 

 phous mass : 



At 18° a region of absorption extending from 499.2 — 537.7, con- 

 sisting of 499.2 — 513.9 very strong band, very badly defined towards 

 violet; 516.9 — 528.2 very strong band, then shade ; and 534.8 narrow 

 faint line ; 535.6 — 537.1 band with maxima 535.6 — 536.4 and 

 536.7—537.1. 



At — 193° this region extends from 498.1 — 526.6 and consists: of 

 498.1 __51 2.6 very strong band, then bands at 513.7—514.1, 514.7 

 —515.3, 516.1—516.7, then shade, 517.6—518.5 band, then again 

 shade, and 519.2 — 526.0 very strong band. 



Another remarkable region extends at 18° from 616,9- 629.3, 

 which consists of 616.9—618.9 faint band; 621.0—622.9 ditto; 

 624.8—626.9 pretty strong band; 628.3—629.3 very faint band. At 

 —193° we see what follows: 616.7—617.6 faint band; 618.9 thin, 

 faint line; 621.1—623.0 faint band; 624.7—625.4 band with strong 

 fine centre; 625.9—626.4 ditto; 627.1 thin faint line; 628.6 -629.5 

 faint band. 



In thinner layers these i-egions diverge even more ; e. g. a rather 

 narrow absorption region branches off from the region 560.1—587.5 



