•238 
W. F. Cole. 
These lines, it is considered, are the characteristic basal spacings of mont- 
morillonite and kaolinite. The 10 A glauconite spacing is greatly reduced in 
intensity. In comparing the two fractions of this sample it appears that the 
■coarse contains more quartz and the fine contains more kaolinite. 
<3) Soil. 
In the coarse fraction quartz is the only constituent that can be definitely 
Tecognised. In the fine fraction however, in addition to the quartz pattern, 
there is a number of lines, including a 7 A line, which disappear when the sam- 
ple is heated to 500°C. These lines, it is considered, are due to kaolinite. 
In both fractions there is a little haematite and /or goethite and a possible 
trace of glauconite. 
Additional effects of Heat Treatment. 
Several changes, in addition to those previously noted, occur in the X-ray 
patterns of the heat treated samples. In most unheated samples a broad area 
of strong intensity extends from 4* 50-4* 10 A, which after heat treatment, is 
resolved into two lines (4-5 and 4-1 A). In the greensand and soil samples 
the line vtth the larger spacing is the more intense whereas in the svibsoil 
■sample it is tlie l(;ss intense. The line with the smaller spacing is due to small 
amounts of candle grease which lined the walls of the celluloid containers in 
whicli the samples were mounted for X-ray analysis. The method employed 
for the preparation of celluloid containers using candle grease ha.s been ])r(‘\'iously 
describ(‘d (4). randlo grease is characterised b}^ two strong lines which occur 
at 4* 12 an<l 3*70 A and which far exceed iii intensity any other lines in the 
candle grease pattern, ft has been freqiumtly noted that a line at 3 • 7 A either 
appears or is inen^ased in intensity as a result of tieat treatmeiit. As the 
effect only ap]H'ared when kaolinite was present in the unheated sample it 
was suggested that tlio lino could be due to a decomposition product of kao- 
linite (9). It is now believed that the ap])earamH^ of this line at 3*7 A is not 
effected by lieat treatment but is (kdorminod by tlu‘ amount of candle grease 
present in the container. This is the origin of the 3-7 A lirie in the soil and 
■subsoil samples. 
It is also noteworthy that the characteristic quartz line at 3*34 A always 
increases or maintains its intensity after heat treatment. 
MICROSCOPIC FXAMINATION. 
A microscopic examination was undertaken with the object of fletermining 
whether or not the o|.)tical pT‘ 0 ]:)ertios of the materials examined were consistent 
with the X-ray conclusions. Wherever possible refractive indices and bire- 
fringence w^ere measured but because of the different stages of alteration 
present, particularly in tlH'. coarser fractions, the refractive indices in many 
cases aT‘(' given only to tlu* second place of decimals. 
Throughout the w^ork the samples wore immersed in mixtures of clove oil 
and a - mouochloronaphthaleno for refractive indices up to 1 -637, in mixtures 
of a— monochloronaphthalene and n- monobromonaphthalene for re- 
fractive indices b('tw’een 1 * 037 and 1 • OGl and in mixtures of e - monobromona- 
naphthalene and methylene iodide for refractive indices higher than 1*661. 
The indices w'ere determined in sodium light by means of a Pulfrich refracto- 
meter. 
