w. y. coi.K. 
'L'aulk I. . 
{'OMPOSITIOX OK THK SOIL COLLOIDS. 
(lU'sult.s of X-rny analysis.) 
Tasuuiniaii. 
West Australian. 
Mineral. 
Tml. 
449. 
A 1351 and A 1340. 
(huu'tz 
.Mucii < 
^ -Much <- 
Much 
Very J^ittle 
i'ossibJo trace 
Ivaoliiiite. 
Little 
Much 
Miieh 
Much 
little 
Mica ... 
— 
— 
— 
Much 
.Montmorillonite 
Little, 
Possible trace 
Possible trace 
— 
— 
liai'matite 
— 
Very Little 
\'ery Little 
Little 
— 
Xole : An arrow (— >) indicates increasing amounts of quartz. A similar assessment 
witli regard to kaolinite in ool, odO and 499 could not b(‘ made. 
Th(‘ soil colloid fi'H('ti()ns from VVi^sttu’u Australia wtnv separated accord- 
ing to lli(‘ Interiiatioiuil M(‘thod which giv('s particles' of an effective- dianieO'r 
of 2jLt and less, d'he soil colloid fractions from 4''asniania wei‘(* se])arated accord- 
ing to the fornun* British systtnn whicdi gives particles of an (*ffecti\‘e diameO'r 
of 1 ■ 4 |Lx and less. From the point of view of this study the main differences 
iTi thes(^ two methods of preparation are ( I ) the 'Tasmanian soil colloid fractions 
ar(^ of a liruu* grad(' than the soil colloid fractions from Western Australia, 
aiul (2) tlte fornuM' wen^ ov<'n-drieii wlannais the latter were air-dried. As 
su]>pUetl for examination the local matcn’iai was still attaclied to tin.' filter paper 
and luid to be removed by scraping witli a glass sli<le. The Tasmanian 
material was supplied in a looser powdm’ed form. 
For further information regarding modilications introduced into the two 
nudhods of s(‘paration used, reference may hi' made to tlu' original articles. 
SOIL (OLl.Oll) 
FRACTIONS FROM THF SALMON (iUMS 
IN WRSTFRN Al'STRAldA. 
OISddOCT 
Both soil colloid fractions A 13el and A 134(> when viewed under tlu* 
microsciqu' were sei'ii to ])e in the form of [)articles up to 50^ aiuL gri'ater in 
diameter. Since (it was claimi'd that) tlu' clay si'parations were (‘omposed 
of pai-liclcs of 2p, and less in effectiv'c diameter, it was assumed that tlu' par- 
ticles viewed beneath the microscope wim-c aggregates of tlie sod colloiil par- 
ticles. In that they exhibited definite iqitical propi'rlies, all these aggregate's, 
in both samj)l('s, elosefv' resembl(>d fragments of n singli' rniuei'al. ddu' optieal 
propt'i’tii'S of these, aggregates, it is eoasideri'd, ure due to the individual com- 
ponents exhibiting uniformity of crystallogruphie orientation. 'Kliis orienta- 
tion of soil colloid and clay partieli's into aggri'gates after iLrying was originally 
obstu'ved by Hendricks and Fi'v (3) and lias betni fnrtlu'r iuv'estigated liy Bray, 
(h-im, and Kerr (4). The aggregates appeai’iug in the soil colloitl fractions 
of A 1351 and A 1340 are larger than those noted l)y Jh*ay, ({rim, and Kerr. 
