INVESTIGATION WITH A ROCK-SALT PRISM. 59 



hence difficult to determine, especially since data are almost entirely 

 lacking at 2.9 /x, just where they are most needed. ( See Appendix VI.) 



Two examinations were made, the first with the myricyl alcohol just 

 taken from the containing bottle. For the second examination several 

 grams of the myricyl were heated to 110° for seven hours in a drying 

 oven, which was sufficient to expel any water present. Immediately 

 after this heating a thin solid film was examined, and the bands at 2.95 /* 

 and 3.43 fjL coincided exactly with those found previously, which would 

 indicate that the 2.95 fx band is not due to water. Whether it is due 

 to the OH-group is a different question. If it is due to OH, then the 

 5.8 iM band should coincide with the water band found by Aschkinass^ 

 at 6.0 IX. The spectrum of myricyl alcohol consists essentially of five 

 large bands. The bands at 1.71 fi, 3.43^1, 6.86 /u., 10.2 ju, and 13.9^1 are 

 closely harmonic. These large bands occur in ethyl alcohol, where they 

 are very much broadened and obliterated in details, due to the greater 

 opacity of the film investigated. 



Like water, the alcohols are very transparent up to i fi, beyond which 

 point they suddenly become more opaque. 



In connection with these alcohols, phenol (fig. 99) and menthol (fig. 

 117) are also to be noticed, since they show the 2.95 /x band, which is 

 characteristic of the alcohols. 



COMPOUNDS CONTAINING THE METHYL (CHg) GROUP. 



Under this heading have been collected a number of compounds that 

 contain CHg-groups. This method of discussing these compounds is 

 of great help in considering certain absorption bands which are prob- 

 ably due to the methane radical. Thus the 3.45 fx band found in 8 

 compounds (mostly alcohols) containing CH3 led Julius- to believe that 

 it was due to that group of atoms. In this present investigation, which 

 covers nearly the whole field of organic chemistry, it remains to be 

 seen how constantly this band occurs. 



NiTROMETHANE (Methye Nitrite). CH3NO2 ; CHg-O-N. (Fig. 33.) 

 In this compound the introduction of the NOj-group has not dis- 

 turbed the 3.41 fx band. Several new ones are to be observed from 

 4 to 6 /A, and are more prominent when examined with the large spec- 

 trometer. The region from 6 to 7 /* is noticeable because of its great 

 opacity, due to a number of large absorption bands. Beyond this there 

 is the same general transparency of 80 per cent, as in the first part of 

 the spectrum, interspersed with sharp absorption bands, especially 

 at 9.1 IX. 



^Aschkinass, loc. cit. 



^Julius : Verhandl. Konikl. Akad., Amsterdam, Deel I, No. i, 1892. 



