19 
more soluble crude material, in fact we are not in a position to 
decide whether there is any hope at all of finding such more valuable 
ore. 
A brief resume of the accepted theory of phosphorus concen- 
tration may serve to draw attention to the many weak points in 
our chain of knowledge which requires further investigation. The 
origin of all the phosphorus now available to man is the phosphorus 
of the primeval surface magma, which has crystallised out in the 
present lithosphere almost entirely as apatite, the fhiophosphate 
of calcium. The average phosphorus content of the lithosphere 
is 0 ■ 28 per cent, of P 2 0 5 . A large decrease in concentration takes 
place when this apatite passes into solution in the soil waters, and 
thence into vegetable ^ organisms. From the latter a small pro- 
portion of the total phosphorus passes into land animals where 
large concentration occurs, placing within reach of man for his use 
an appreciable tonnage of u bone phosphate.” By far the greater 
part of the phosphate dissolved from weathering rock passes how- 
ever into the ocean in an extreme state of dilution, where it is first 
absorbed by marine flora, subsequently by the intervention of fish, 
arthropods and mollusca, and in past ages by marine reptiles, 
reaching an appreciable concentration in the bony framework of 
such creatures. Fish bones as such, are not used to any great 
extent as a phosp hatic manure, but the ingestion of bony fish by 
other carnivorous fish as well as by reptiles and birds, all. of which 
excrete the greater part of the phosphatic material in a new and 
more soluble form, has led to the chief concentration upon which 
man depends for his supplies of agricultural phosphorus. The 
guano deposits and associated rock phosphates are fairly well 
known, though the total number and chemical nature of the various 
minerals occurring in them is not yet known with any certainty. 
The story of the fish and other phosphatic excreta which passes 
directly into the water of the ocean, and how this came to be col- 
lected together into beds of coprolite and of phosp hatised wood, 
both important fertilisers in Europe and America, and likely to be 
in Western Australia, is at present a closed book. 
There is plainly room for a large amount of scientific work in 
the story of the cycle of natural phosphorus, including investiga- 
tions of the actual organisms which are capable of secreting plios- 
p hatic materials, and the form and proportions in which it is 
secreted, the concentration and chemical composition of the phos- 
phorus compounds formed at all intermediate stages, and their 
solubility in natural waters, and finally, the composition and 
chemical properties oi‘ the many minerals occurring in the natural 
concentrations now used or still lying useless through insufficient 
concentration or deficient solubility. 
Prof. Samoilow has devoted some time to this phosphorus 
question, but complains with others of the almost total absence 
