74 The N.Z. Journal of Science and Technology. [Mar. 
enough, for a moment’s thought at this point should reveal the fact that 
agriculture itself is neither more nor less than applied plant and animal 
ecology, and that long before the name “ ecology ” was coined the agri¬ 
cultural investigator had been more or less of an ecologist. 
And plant ecology itself, is it a branch of botany alone ? A branch of 
botany it certainly is, since the behaviour of plants is its theme. Never¬ 
theless, the botanist who pursues ecology must be equipped almost beyond 
human powers or he must seek the collaboration of other men of science, 
notably the physicist, the chemist, the geologist, the zoologist, and the 
meteorologist. 
Such an equipment could undertake that primary requisite for agri¬ 
cultural advance in this country — an agricultural survey conducted on 
ecological lines with a view to an accurate classification of the farm-lands 
of the Dominion. Nothing is more urgently needed in the interests of New 
Zealand agriculture. Once the different classes of agricultural land are 
segregated for the next scientific process—intensive ecological investigation 
and experiment—then it can be truly said that the era of the New Agri¬ 
culture has commenced and that the day of intensified national prosperity 
has dawned. 
ESTIMATION OF POTASSIUM IN AGRICULTURAL 
SAMPLES BY MEANS OF PERCHLORIC ACID. 
By B. C. Aston, F.I.C. 
In many elementary laboratories and some advanced ones compelled to 
practise economy the estimation of potassium has been barred to students 
owing to the high price of the platinum salts (platinum is now £13 per 
ounce) used in the method of analysis. The perchloric acid method which 
is now available makes the determination of the potash in agricultural 
samples possible with very little expenditure for reagents. Inquiries have 
been received with regard to the details of this new method, which is 
here reprinted in summarized form for general information. 
The excellent paper by Mr. William A. Davis, of the Bothamsted 
Experimental Station, entitled “ The Estimation of Potassium, especially 
in Fertilizers, Soil Extracts, and Plant-ashes,”* will be hailed with pleasure 
by most agricultural analysts. Mr. Davis has examined the platinum 
method (previously generally used in New Zealand) and the perchloric 
method very critically. Concerning the former he says,— 
“ To sum up : the platinum method is liable (1) to give high results 
unless 80 per cent, alcohol is used ; (2) to give low results when 80 per 
cent, alcohol is used, owing to the relatively high solubility of K 2 PtCl 6 ; 
(3) to necessitate great care when sulphates are present; high results may 
easily be obtained unless the precipitation of the sulphate by barium 
chloride is very exactly carried out. . 
“ In view of the many other real advantages possessed by the per¬ 
chlorate method, and the undoubted fact (as will be demonstrated later) 
that it gives accurate results without any very special precautions 
having to be taken, it is contended that the platinum method should be 
abandoned on account of its uncertainty, cost, and special difficulties of 
manipulation. 
* Journ . Ag. Sci., vol. 5, pt. i, Oct., 1912, 
